MESA Training This series of exercises will introduce you to many of the options that are available in MESA for the design and QC of 3 surveys! "t is a good idea to refer to the MESA MESA user#s manual for more details about the features described in these exercises!
• • • • • • • • • • • • • • • • • • • • • • • • • •
$rogram $urpose!!!!!!!!!!!!!!!!!!!!!! $urpose!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!! % &M& atabase 'iles!!!!!!!!!!!!!!!!!!!!!!! 'iles!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!% !!!!!!!!!!!!% Steps in Survey esign!!!!!!!!!!!!!!!!!!!!!!!!!!!! esign!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!! ( )and 3 Seismic Survey Classifications!!!!!!!!!!!!!!!! Classifications!!!!!!!!!!!!!!!! !!* &eometry Examples!!!!!!!!!!!!!!!!!!! Examples!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!+ !!!!!!!!!!!!!!!!+ Seismic ata $rocessing "ssues!!!!!!!!!!!!!!!!!!!!!!!!!!!! "ssues!!!!!!!!!!!!!!!!!!!!!!!!!!!! ,3 "nformation &athering!!!!!!!!!!!!!!!!!!!!! &athering!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!,* !!!!!!!!!!,* E-uations .sed in Survey esign!!!!!!!!!!!!!!!!!!!!!!!!!!,+ Survey Analysis and QC!!!!!!!!!!!!!!!!!!!!!!! QC!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!%/ !!!!%/ Shooting Techni-ues Techni-ues Compared!!!!!!!!!!!!!!!!!!!!!!!!!! !!%0 Ex 1,2 asic MESA MESA .sage!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!%4 .sage!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!%4 Ex 1%2 )ine5ric6 )ayout 7ptions 7ptions !!!!!!!!!!!!!!!!!!!!!!!!!(% Ex 132 .nit Template Template )ayout!!!!!!!!!!!!!!!!!!!!!!!!! )ayout!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!0, !!!!!!!!!0, Ex 1(2 The esign esign &uide!!!!!!!!!!!!!! &uide!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!! !!!!!!0* Ex 102 "mporting Survey 'iles!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!*3 Ex 1*2 Marine esign!!!!!!!!!!!!! esign!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!! *8 Ex 1+2 .sing &M& "mage!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!+ ( Ex 182 Source and 9eceiver 9eceiver Editing!!!!!!!!!!!!!!!!!!!!!!++ Editing!!!!!!!!!!!!!!!!!!!!!!++ Ex 142 7ffset and 9ectangular 9ectangular Shooting!!!!!!!!!! Shooting!!!!!!!!!! !!!!!8% !!!!!8 % Ex 1,/2 Automatic Automatic Templat Template e Centering!!!!!!!!!!!!!! !!!8* Ex 1,,2 1,,2 Salvo Shooting!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!4 Shooting!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!4 , Ex 1,%2 )abel Shooting!!!!!!!!!!! Shooting!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!4 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!4 3 Ex 1,32 Multi:Survey Capability!!!!!!!!! Capability!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!4+ !!!!!!4+ Ex 1,(2 .sing Advisor!!!!!!!!!!!!!!!! Advisor!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!! ,/3 Ex 1,02 Attributes Attributes and 'iltering!!!!!!!!!!!!!!!!!!!!!!!!!! 'iltering!!!!!!!!!!!!!!!!!!!!!!!!!!!!,/* !!,/* Ex 1,*2 isplaying ata!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ata!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ,,* ,,*
Program Purpose MESA provides provides a great d eal of flexibility in 3 survey design and analysis; whether the survey is a land; transitional area; ocean bottom cable; or marine design! "magery; "magery; contour information; information; and cultural features
77A; and S$S; in addition to shooting scripts for "nput57utput and A9AM ac-uisition systems! The completion of a survey design in MESA generates a &reen Mountain &eophysics &eoScribe geometry database; thereby completing a ma?or portion of the initial pre:stac6 processing wor6 while still in the field! These database files are transportable across various hardware platforms; platforms; ma6ing MESA a practical tool for field and office environments!
GMG Files and the Database The following set of files represents what &reen Mountain &eophysics refers to as the MESA or &eoScribe database! These files are a combination of ASC"" ASC"" and binary files and combine to hold all of the information needed to define the geometry
File Extension
2
Format
Description
!atr
inary
Attribute information for receivers
!ats
inary
Attribute information for sources
!bin
inary
in information; siBes
!bmp
inary
$icture for open database preview display
!cf,
ASC""
Configuration file for the receiver spreadsheet
!cf%
ASC""
Configuration file for the source spreadsheet
!def
ASC""
efault values for MESA to use with this survey
!fbt
inary
''" info and first brea6 pic6s
!hdr
ASC""
eader information for S$S outputs
!idd
inary
"mage ray attribute information
!inr
ASC""
"nstrument information for receivers
!ins
ASC""
"nstrument information for sources
Program Purpose MESA provides provides a great d eal of flexibility in 3 survey design and analysis; whether the survey is a land; transitional area; ocean bottom cable; or marine design! "magery; "magery; contour information; information; and cultural features 77A; and S$S; in addition to shooting scripts for "nput57utput and A9AM ac-uisition systems! The completion of a survey design in MESA generates a &reen Mountain &eophysics &eoScribe geometry database; thereby completing a ma?or portion of the initial pre:stac6 processing wor6 while still in the field! These database files are transportable across various hardware platforms; platforms; ma6ing MESA a practical tool for field and office environments!
GMG Files and the Database The following set of files represents what &reen Mountain &eophysics refers to as the MESA or &eoScribe database! These files are a combination of ASC"" ASC"" and binary files and combine to hold all of the information needed to define the geometry
File Extension
2
Format
Description
!atr
inary
Attribute information for receivers
!ats
inary
Attribute information for sources
!bin
inary
in information; siBes
!bmp
inary
$icture for open database preview display
!cf,
ASC""
Configuration file for the receiver spreadsheet
!cf%
ASC""
Configuration file for the source spreadsheet
!def
ASC""
efault values for MESA to use with this survey
!fbt
inary
''" info and first brea6 pic6s
!hdr
ASC""
eader information for S$S outputs
!idd
inary
"mage ray attribute information
!inr
ASC""
"nstrument information for receivers
!ins
ASC""
"nstrument information for sources
!lbs
ASC""
)abel shooting information
!mar
inary
Marine survey information
!mas
ASC""
atabase parameters and status flags
!mdd
inary
Model attribute information
!mdl
ASC""
Aperture model information
!mid
inary
Midpoint information; offsets; aBimuths
!mrl
inary
Streamer marine receiver locations
!mut
ASC""
Mute function information
!ndd
inary
@ormal ray attribute information
!pat
inary
Source5receiver template relationships
!rdd
inary
7ffset ray attribute information
!rfi
ASC""
'ilter settings for receivers
!rln
ASC""
)ine names for receivers
!se-
ASC""
&eneral shooting se-uence description
!sfi
ASC""
'ilter settings for sources
!sln
ASC""
)ine names for sources
!sor
inary
Source numbers and coordinates
!sta
inary
9eceiver numbers and coordinates
!tpl
inary
Source to receiver patch relationship
!unt
ASC""
Configuration of the unit template
!xcl
ASC""
Exclusion Bone type; siBe; and all coordinates
3
Other GMG Files used or created in MESA File Extension
4
Format
Description
!cfg
ASC""
Configuration file used to import survey files
!csi
ASC""
Color scale settings
!cyr
inary
&M& contour file
!lyr
inary
&M& image file
!nop
ASC""
MESA midpoint exclusion output file
!ptn
ASC""
MESA pattern output file
!scr
either
"nput57utput script file
!sts
ASC""
MESA land statistics5cost output file
!tdf
ASC""
Trace data format file used to import SE&D files
!vyr
inary
&M& vector file
Steps in Survey Design
Step 1 !uilding an "ideali#ed$ survey MESA provides several methods for defining a survey! 1% Direct layout and shooting .sing the source and receiver layout dialogs; you can create orthogonal 77A; SE&:$,; and S$S! "f ASC"" relational files or ASC"" or binary shooting scripts are also available; they can be imported; as well!
Step & +reating a "real -orld$ survey 7nce the initial design parameters have been set for the survey; aerial and satellite imagery; scanned topographic maps; contour displays; and5or files containing cultural information
5
Step ) 'pdating -ith surveyed coordinates The theoretical survey design can easily be updated with actual coordinates from the survey crew on a shot by shot; swath by swath; or daily basis through the ASC"" file import option! The new coordinate information may be provided as absolute values or shifts from the original position! Analysis of the ongoing ac-uisition; via the bin attribute displays; allows for the repositioning and5or addition of sources and receivers in order to compensate for any deficiencies which may have appeared in the desired fold; offset; or aBimuth distributions because of conditions in the field!
6
.and )/D Seismic Survey +lassi,ications Jim Musser, Director GMG Energy Services (ype "n:)ine Swath
Applicable Areas 7pen Terrain
Advantages @arrow aBimuth data can be processed and analyBed li6e %: seismic
Disadvantages $oor cross line statics; high S9C and 9CF line density; very sensitive to o bstructions
7rthogonal
All Terrains
Gide aBimuth; good for 3: M7; can solve cross line statics; industry standard; economic operations
Must use 3: algorithms; cannot use simple % ':> algorithms
ric6
7pen Terrain
)i6e orthogonal; plus improves near offset and overall offset distributions
iscontinuous source lines are difficult in ?ungle and in some other terrains
Slant
All Terrains
"mproves overall offset coverage; better offsets for AF7
Surveying and line clearing on source lines are longer due to diagonal line orientation
utton $atch
7pen Terrains; Allows sparser source points; 'arm )and; Arctic; efficient use of large channel esert systems
Fariable )ine Spacing
All Terrai Terrains ns
Asymmetric Spread Spread
9andom
Complex to plan
Modification of orthogonal; orthogonal; bric6; or Complex to plan slant design with similar advantages to each; plus guarantees surface consistency
All Terrai Terrains ns
Modification to orthogonal; orthogonal; bric6; or Same as for orthogonal; slant design with similar bric6; and slant designs advantages to each; plus longer offset with less recording e-uipment
All Terrains
Surface consistent; minimiBes ac-uisition footprint
Complex to plan and operate
7
Geometry Examples Any of the the follow following ing geometri geometries es can be built built in MESA MESA by using using the unit unit templat template e option option or by direct directly ly placing the sources and receivers before shooting! 'or each geometry; there is a view of the .nit Template window followed by a view of the esign window; as well as the main points for and against each survey type!
8
*nline S-ath shooting / Marine li0e $ros2 Cons2
Simplest geometry for 'SF type recording systems! $oor aBimuth distribution; poor coupling; high fold!
9
Orthogonal or straight line shooting $ros2 Cons2
10
Fery simple geometry to lay out in the field! Comparatively expensive and yields largest Hmin! 9e-uires good access for sources and receivers!
!ric0 shooting $ros2 Cons2
Smaller Hmin reasonable aBimuth and offset distribution with potential for statics coupling! 9e-uires good access for both sources and receivers so not suited to areas with access problems! Excessive long offsets may result with whole survey; or replanting of geophones!
!utton Patches
11
$ros2 Cons2
Efficient utiliBation of large channel systems with minimum source access and effort! Can re-uire large numbers of sources! 9e-uires computeriBed planning! CM$ fold does not yield same offset5aBimuth distributions in ad?acent bins!
ig#ag
12
$ros2 Cons2
Smaller Hmin with good offset and aBimuth distribution! 7nly good in conditions of open access such as deserts!
13
Seismic Data Processing *ssues 2elated to Geometry
Migration Migration creates some profound re-uirements on survey design! iffracted events in the subsurface impose the re-uirement to sample more time and wider areas; in order to capture enough of the diffraction to collapse its energy! This almost always will re-uire the design geophysicist to record seismic data over an area which is much larger than the actual prospect area! The calculation of this Imigration apertureJ is described in the E-uations section!
2e,raction Statics "f you are designing a survey in an area where significant weathering and statics problems may exist; you will want to focus some energy on optimiBing your survey to solve these problems! Several refraction statics algorithms exist! Most of these algorithms are primarily numerical e-uation solvers; which are dependent on statistical redundancy for the best solutions! Statics coupling does not play a large role with most refraction statics algorithms because the statics are not measured in the midpoint domain; and there is no structural or 9@M7 term to solve in the standard e-uation! Therefore; anything which improves the -uality of the first brea6s will contribute to enhanced refraction statics solutions! A single point dynamite source with no significant receiver field arrays will produce the best results! &eometries with receiver lines which are not straight produce first brea6s which can be very difficult to pic6! Statistical algorithms will perform best if the statistics provided are consistent and well sampled! This would re-uire the designer to balance source point fold and receiver point fold! Dour final design should produce source5receiver fold of * or more! Split spread type shooting creates surveys which have reciprocal travel paths! Many types of algorithms depend on reciprocal paths to build stable solutions! 7ff:end shooting schemes should be considered as a last resort! Shallow refractors will re-uire narrow receiver line spacing or they will not be well sampled!
2e,lection Statics "t is our experience that most regular 3 designs will decouple in the traditional sense without editing! Ghat saves the designer in most cases is the fact that sources and receivers are shifted around in the field; providing a pseudo:randomiBed version of the original plan! Ghile this randomiBation tends to have a coupling effect on the survey; it does not however guarantee that the survey couples! The noise plot in MESA demonstrates the degree of coupling which a survey design possesses!
14
"f you understand any potential statics problems which may exist in the survey area; you can consider the way in which your design will sample the statics problem! Extremely long wavelength statics or large 6nown statics may affect the sampling decision made by the designer; relating to crossline length or receiver template siBe!
3elocity Many of the best 3 velocity algorithms are currently using aBimuth as well a s other information to build plots and aid in the determination of stac6ing velocities! These types of algorithms re-uire that bins sample offsets and a Bimuths with enough statistics so the data can be analyBed! Felocity analysis is usually performed on a super bin; so users should be aware of how the bin:to: bin relationships of offsets and aBimuths will complement each other! )arge gaps in offset distributions or absence of near traces on shallow reflectors can contribute to problems in the analysis!
Deconvolution Surface consistent deconvolution presents the same re-uirements that reflection statics does! Evenly sampled data in both the source and receiver domain will contribute to better solutions! At far offsets; the data often becomes distorted by incidence angle and emergent effects; ma6ing far offsets unusable for the derivation of the deconvolution operator! This imposes additional re-uirements that the near traces need to be well sampled to provide the information re-uired by the deconvolution algorithm!
DMO 4Dip Moveout5 M7 will function best if a survey is sampled at all offsets and all aBimuths! 7bviously; this is not possible! Modern processing techni-ues can ma6e up for the lac6 of sampling re-uired; but a well:sampled survey in both offsets and aBimuths will produce better solutions! M7 is 6nown to create amplitude artifacts in 3 surveys! This amplitude effect is called geometry imprinting; artifacts; or geometry Ifoot print!J The imprinting effect is reduced if a broad range of aBimuths is collected! As has been demonstrated; this effect becomes more pronounced for steeper dips and shallower targets
+oherent 6oise Attenuation Much research has been done in recent years relating to attenuation of coherent noise with ac-uisition geometry! The Ibleed throughJ effects of source:generated noise differ depending on the ac-uisition design! Certain geometries will attenuate noise better than others will! )oo6ing at this issue in a post:stac6 or post:migration environment is the current wor6 of researchers at several ma?or companies! @oise plots and Array Analysis from the Advisor menu can be used to perform source and5or receiver array noise a nalysis!
15
2elative Amplitude 4A3O7 A3A5 AF7
16
*n,ormation Gathering
ere are some issues to consider during survey design! This list is not exhaustive!
Exploration Ob8ectives Type of feature
(arget Description epth; Arrival time; Average velocity to target; "nterval velocity at target; ip
Operational +onsiderations Expected noise
17
E9uations 'sed in Survey Design
!in Si#e To avoid spatial aliasing in the data2 in siBe at subsurface K
V i 4 f sin α
where Fi L interval velocity at target f L maximum expected fre-uency from target α
L dip angle
6ear O,,set 2ange Hnear Fshallow x Tshallow where / to H near is the offset range over which 3 fold or more is needed to stac6 the shallowest re-uire horiBon Fshallow L Mute velocity in the shallowest section
.ong O,,sets Hlong L Fnmo
2
∆t
+
2 * t (0 ) * ∆t
where Nt L t
18
Spatial 2esolution Minimum 3ertical 2esolution L Fi 5 < (!/
where Fi L the interval velocity at the target .ateral 2esolution L <3 x Fertical 9esolution= 5 sin <3/ °=
Maximum dip is usually a value which is no less than 3/ °! "f structural dips are less than this; it is a conservative practice to use 3/ °!
Fold +overage "f previous % data exists for an area with good signal to noise ratio; a Irule of thumbJ for 3 fold is to use between one:half to two:thirds of the % fold!
Source Density 4sources per s9uare 0ilometer5
Source ensity <@S= L P% <'old x ,/ *= 5 <9 x x x y= where
9 is the number of recorded channels x is the inline bin dimension y is the crossline bin dimension
6ote this e9uation re9uires that bin dimensions be in meters%
Source .ine Spacing
Source )ine Spacing L ,/ * 5 <@S x min= where
min is the smallest bin dimension @S is source density
6ote this e9uation is true only i, the layout geometry is split spread%
19
Maximum Minimum O,,set MaxMin 7ffset ≅ < where
RL2
+
SL2
= : SA
9) is receiver line spacing S) is source line spacing SA is the salvo ad?ustment! The salvo ad?ustment corrects the offset for sources not being concurrent with receivers! The ad?ustment is
Migration Aperture "f the survey design can collect emergent energy out to 3/ ° from the normal; then processing can migrate 40R of the energy bac6 to the diffracting point! Migration aperture L tan <3/ °= L /!08 where
20
is depth
Survey Analysis and :+ After designing any survey; the shooting geometry should be analyBed! MESA contains several QC tools; such as template viewing and editing; source and receiver numbering and ordering; and definition of the shooting order; for use in the analysis process!
Shooting Ghen the survey is designed using the .nit Template; the sources will be fired as they are positioned in the esign window! Similarly; when using the S$S import; the shooting is defined by the relational file! Shooting can also be defined using script files from "57 systems! owever; if you are starting from the initial layout; or if you add extra sources; then the shooting se-uence must be defined! "t is important to understand the terminology used for shooting in MESA! 'or our purposes; inline for receivers is the direction from one receiver to the next within the same line! Similarly crossline is the direction from the first receiver line to the second! 'or sources; inline is the direction from one source to the next within the same line; and crossline is the direction of the first source line to the second! Thus; in an orthogonal geometry inline for sources is perpendicular to inline for receivers! To use any of the user:defined shooting se-uences it is important to recogniBe the approaches which the program ta6es! Several of the shooting se-uences use the internal numbering within MESA rather than the labeling! Automatic Template Centering; Salvo; Swath Se-uence; &eneral Se-uence; and Manual Shooting are all based on the internal numbering! )abel ased Shooting and "mport Templates use the labeling to determine source O receiver relationships! 7ffset and 9ectangular Shooting ignore labeling and simply use offset values for determining the receiver patch! "n the esign Gindow; holding down the Shift 6ey and )eft:Clic6ing on any source or receiver will provide you with the following information2
21
"n the above example the labeling and internal numbering are consistent! "n this example the labeling# is the user:defined */,8# and is an editable -uantity! The internal numbering for this receiver is the combination of the non:editable line index and the position in line! "t is important to recogniBe this when considering receiver5source deletion as this will have an effect on the shape and position of the template! 7ften it is more convenient to turn off#
'urther information on receivers and sources is accessed and edited through the appropriate edit modes or spreadsheets! 7ffset and 9ectangular shooting are the easiest methods for shooting a survey! "n either case; the only thing that must be done is setting the offset ranges! All of the receivers that are within the offset ranges for a source are added to the template for that source! These methods of shooting are useful in areas with irregular receiver geometry! To use the other methods of shooting; a template must first be created! The template is defined by specifying the number of receiver lines; number of receivers per line; and a starting receiver! More complex templates can be created by using the Edit Templates option available in the Shooting dialog! Automatic Template Centering is the most commonly used shooting method in MESA! 'or this method; the closest receiver to a source point is located and used as a centering point for the
22
entire template! "t is also possible to s6ew the template from the center by using the Template S6ewing ialog! S6ewing can be used to perform off:end shooting geometries! Salvo Shooting handles scenarios of multi:source salvos that span receiver lines and salvos that re-uire restricting the inline template roll! Salvo shooting is very well suited for slant geometries and bottom:cable designs! "n our terminology; a salvo is a set of source points
)abel ased Shooting shoots surveys using the labeling numbers; not the internal numbering! "t is convenient for shooting geometries which have a large number of sources shooting into a receiver patch
23
oth the Swath and &eneral Se-uence shooting functions are largely archaic! Most surveys can be shot more easily using another techni-ue in the program! owever; the methods are left in the program in case some unusual circumstance warrants their usage! These methods will only wor6 if your survey design is orthogonal and very; very regular! Swath Shooting can be used for very simple shooting situations2 only two roll instructions from the initial template and source positions are allowed! To use Swath Shooting; the rolls within each swath must be consistent; and the roll from swath to swath must be consistent; therefore it is not possible to shoot a bric6 survey in a single pass via Swath ShootingU 7ne instruction is used to specify how to move the template along the swathV The other instruction specifies how to move from swath to swath! &eneral Se-uence Shooting is used for more complicated shooting situations; such as bric6s! "n &eneral shooting; there can be an unlimited number of shooting instructions! Each instruction can move the receiver template inline and5or crossline; and each instruction can move inline and5or crossline to the next source! The goal of &eneral shooting is to generate a set of instructions which can be repeated to shoot all or a portion of the survey! There are two types of instructions in &eneral shooting; W"nner MovesW and W7uter Moves!W "nner Moves can be thought of as instructions which get repeated until the edge of the survey is h it; much li6e the Wfirst move directionW instruction in the Swath shooting methodology! 7uter Moves can be thought of as instructions which get carried out when an "nner Move instruction cant be carried out
24
mode! "f sources are moved after firing; the midpoints will also be shown moving! This is a useful diagnostic when trying to increase the fold in an exclusion Bone either by moving existing sources; firing into new templates; or adding compensation sources!
There are several 6eyboard shortcuts that can be used to -c or speed up shooting2
;ey
Action
T S
Toggles on5off the template while shootingV Source colors continue to update! Toggles on5off real time updating of the display while shooting! The display updates after a group of 0// sources has been fired! $ause the shooting! The current template is displayed! $ause the shooting and step to the next source while paused! 9esume shooting after pausing 'ully unBooms the esign Gindow Cancels shooting
$ @ C Esc
25
Shooting techni9ues compared Shooting (ype Automatic Template Centering
.ses
*n,ormation Surveys with fairly uniform receiver lines; surveys with regular or irregular source lines
)imitations
Template siBe is static
.ses
Slant surveys; source patterns that span receiver lines
)imitations
Templates may not position correctly at survey edges; always uses all sources between receiver lines
.ses
Surveys with highly irregular receiver positions; surveys with regular or irregular source locations; limited offset range shooting
)imitations
Creates a lot of templates; slower shooting method; only creates a circular patch
.ses
Surveys with highly irregular receiver locations
)imitations
May not 6eep all sources in a salvo together in the same patch
.ses
Creating complex templates; creating large source patches
)imitations
Survey labeling must be regular and consistent
Swath Se-uence Shooting
.ses
Surveys with regular source and receiver lines
)imitations
Method is extremely sensitive to survey irregularities; difficult to use; other shooting options produce the same answer
&eneral Se-uence Shooting
.ses
Surveys which are difficult to shoot with Swath Shooting in one pass
)imitations
Method extremely sensitive to survey irregularities; most difficult method to use; other shooting options produce the same answer
.ses
&ood for shooting individual sources that have been added; good for lassoing large groups; possible to shoot individual sources which cannot be fired in any other way
)imitations
Fery labor intensive; Edit Templates feature offers better method of manual shooting
.ses
Shooting complicated geometries e!g! button patch; slash <ig or ag= and variable spacing; use with a pre:defined surface or sub: surface polygon fill!
)imitations
.nwanted receivers may be generated; survey layout coincides with shooting so not applicable to surveys which are already laid out!
Salvo Shooting
7ffset Shooting
9ectangular Shooting
)abel ased Shooting
Manual Shooting
.nit Template Shooting
26
!inning The default bin siBe is half the source and receiver interval! The bin grid will default to the minimum and maximum receiver bounds rather than the edge of the midpoint coverage! The siBe; orientation and relative positioning of the grid are set by the mouse or 6eyboard and can be changed for the analysis of various processing parameters! "t is also possible to use place:holders or 6ey:positions to align the grid and thus maintain a consistent grid between design and processing stages! "t is possible to save and review binned attributes by naming the calculation and then later selecting it! The 'old Selection option in the in Analysis menu is used to select the named calculation to use! The 'old Compare option is used to compare two named fold calculations! "t creates a fold difference plot! @2 "f you redefine the bin grid or reshoot the survey after calculating attributes; you will need to recalculate to view the effect!
Attribute +alculation MESA allows for several types of bin attribute calculation2 'old only
a -uic6 loo6 techni-ue for analyBing fold
'575A
create all fold; offset and aBimuth attributes for the whole survey
C9$ binning
used in combination with 3Aims this function provides for binning on a subsurface structure thus producing C9$ rather than CM$ cover
Multi:Falued
lets you examine fold for particular instrument component combinations
'lex inning
set a flex radius to include midpoints from surrounding bins in each bin
Partial survey The Calculation Extents options can be used to calculate the desired information for a limited geographical region of interest! The region can be defined either manually by entering a range of grids to use or by graphically selecting the grid range with the mouse! 7nce the bin attributes have been calculated a series of QC plots become available in the esign Gindow and under the in Analysis menu! $lease be aware that the bin and midpoint files can be very large for large surveys and therefore calculation and display may ta6e some time!
27
(he !in Attribute Plot This information can be accessed through either the esign Gindow or the in Attribute Gindow! These windows provide access to the main survey QC screens! Ghen the in Attribute Gindow is opened; the bin grid is displayed! After the Mouse "dentification mode has been set to ins; hold down the Shift 6ey and )eft:Clic6 on a bin to display the bin information dialog! 'old can be shown as a color:fill plot or numerically! The colors in the display may be changed by using the interactive color scale! The entire fold can be displayed; or ?ust the fold for limited offset or aBimuth ranges! "t is also possible to set a Mute 'unction
(he !in Attribute Graph This plot provides a mechanism for viewing all the information along a bin line in either the inline or crossline direction! The in &raph 7ptions dialog allows the user to select the active parameter for the y:axis and for the color; both to be plotted against bin number on the x:axis! Thus each vertical column is the CM$ bin containing cells# of offset usually chosen as the group interval! The default is to plot offsets on the y:axis and aBimuths by color as this is the most useful for viewing the effect of exclusion Bones! This plot appears as a series of F# shapes in which all of the possible offsets are defined for use in velocity analysis! The Show Cross Section in esign Gindow option plots a line to show the currently displayed bin line in the esign Gindow!
(he !in Statistics
28
E=E2+*SE >1 // !asic MESA 'sage This exercise shows the basic se-uence of steps for creating a survey in MESA! Dou will be laying out sources and receivers; translating the survey; shooting the survey; defining a bin grid; calculating diagnostics; and outputting the survey to SE&:$, files! ifferent types of geometries can be created in MESA! )ayout types such as slant; Big:Bag; radial; button; random; etc! can all be created! This exercise will focus on a simple; straight line orthogonal layout! 1%5
'rom the .ayout menu; select the 2eceivers option! This will open a submenu of receiver layout options! 'or this exercise choose the .ines?!ric0s option! This will open the I)ine5ric6 )ayoutJ dialog!
The I)ine5ric6 )ayoutJ dialog is used to define the parameters for the receivers in a survey! )aying out sources uses a very similar dialog! Dou need to specify the inline and crossline spacings; line bearings; starting coordinates; and survey siBe! Survey siBe can be set in several different ways in MESA2 first by declaring the number of lines and the number of receivers to be included in each of those lines; second by declaring the inline and crossline siBes; or third by filling in a previously defined area; either an exclusion Bone or source lines! )ater exercises will show how to use these fill options for determining survey siBe! The bric6 options are used to create bric6 surveys instead of orthogonal! "nstrument types and numbering can also be defined in this dialog! 'ill in the receiver I)ine5ric6 )ayoutJ dialog as shown on the next page!
29
Clic6 on the 6umbering button to specify the survey numbering you wish to use! Any numbering that you set in this dialog will be used for any sources or receivers you lay out afterwards! 'or this example; use MESA#s default numbering system!
Also note that you can specify receiver and source line prefixes and suffixes; which can be alphanumeric!
30
Clic6 on the *nstrument button to enable the following dialog; in which you can define various instrument types2
Again simply use the default value! Close the Iefine "nstrumentJ dialog and press the O; button in the I)ine5ric6 )ayoutJ dialog to lay out the receivers! &%5
@ow lay out the sources! Select Sources /@ .ines?!ric0s from the .ayout menu! This will open the I)ine5ric6 )ayoutJ dialog for sources! Dou will need to fill in the dialog as it appears below! "t wor6s exactly li6e the receiver dialog! After you parameteriBe your source layout and press O;; the sources will be displayed and your esign Gindow should loo6 li6e the picture on the next page!
31
)%5
Dou can set the units for the measurement system at any time! Select the 'nits option from the .ayout menu and toggle on the desired system of units2
%5
@otice that the header line on the esign Gindow reads IKuntitledXJ! This indicates that the database has not been saved! Save the design by opening the File menu and selecting Save Database! Enter the name Iexercise/,J at the File 6ame prompt and press Save! IKuntitledXJ is now replaced by Iexercise/,J in the esign Gindow title bar! Dour design is a <+4%/# x +4%/#= %!%0 s-uare mile 3: survey! 9eceiver interval is ,,/#; receiver line interval is ((/#; source interval is ,,/# and source line interval is 88/#! The receiver line aBimuth is 4/ degrees from true north and the source line aBimuth is true north! The initial source and receiver positions have each been offset from
32
B%5
Select (ranslation from the 'tilities menu! The ITranslation59otationJ dialog is used to change the coordinates and the aBimuths of the survey! Changing both the coordinates and the aBimuths is a two step process! 'irst do the Coordinate Translation! This can be done graphically or by specifying actual figuresV fill it in as below and press O;%
@ext open the ITranslation59otationJ dialog again and do the Coordinate 9otationV this can be done graphically or by specifying figuresV again fill it in as below and press O;%
33
$ress the Full 'n#oom button on the oom toolbar in the esign G indow and you will see that the survey has been translated to the new location and rotated to the specified angle!
34
C%5
The esign Gindow should now loo6 as it does above! The oom toolbar; shown below; is used to ad?ust the display and contains the 2ange?!earing tool! Dou can Boom in on the survey with the right mouse button! $ress and hold the right mouse button to draw a Boom rectangle! Ghen you release the right mouse button; the display will update to show you ?ust that region! Dou can perform the Boom function multiple times! To Boom out one step from the current Boom level; press the oom Out 1 .evel button; the magnifying glass with the O signV if you are already at the full Boom level pressing the oom Out 1 .evel button Booms you out by another 0/R! To Boom to ,//R of the full view; press the oom Out 1 button; the magnifying glass with the letter '! The Aspect 2atio button has the xLy on it! As long as this button is down; the survey is always displayed at a fixed ration! "f the button is not depressed; then the survey will be displayed at the ratio defined by the siBe of the esign G indow!
%5
7pen the Find 2ecord or !in button submenu and verify that the mouse is set to identify 2eceivers and Sources! old down the Shift 6ey and )eft Clic6 on a source in the esign Gindow! The following dialog will appear2
35
Change any of the editable fields and press Apply to edit the information for this source! $ress the Spreadsheet button to go to the spreadsheet entry for this source! $ress the *nstrument button to modify the instrument settings for this source! @otice that the live receiver template for this source is highlighted in the esign Gindow if you have shot your survey! olding Shift and )eft Clic6ing on a receiver will open the same dialog with the information for the receiver! 7nce you are in the spreadsheet
36
%5
@ow you can create a template and shoot your survey! $ress the Shoot button to open the IShootJ dialog! Many different methods of establishing source and receiver relationships are available in MESA! As the shooting process progresses; source points will change color in the esign Gindow and their associated receiver patterns will be highlighted! Selecting the appropriate shooting algorithm will depend upon the geometric relationship between your source and receiver points! Dou will be using Automatic (emplate +entering in this exercise! )ater exercises will demonstrate how to use some of the other shooting methods!
7nce you have opened the IShootJ dialog; press the +reate (emplate button and define an 8 line by (8 receiver shooting patch! This template will be displayed in the Select (emplate list in the Template 7ptions section! Select the template and press the Shoot button! The dialog will close and MESA will begin to simulate shooting the survey in the esign Gindow! 7nce it is finished shooting; all of the sources will be displayed in red; meaning they have been fired! Select Edit (emplates from the 'tilities menu to view the results! )eft clic6 on a source to view the receiver patch for that source! &o bac6 into the 'tilities menu and select Edit (emplates again to exit this mode!
37
H%5
38
The next step is to define the bin grid! Select !in Grid Settings from the Display !ins button submenu to open the Iin efinitionJ dialog! 'ill in the *nline and +rossline !in Si#e boxes as shown! Clic6 on the Auto Fit button to automatically fill in the remaining text boxes! Select O; and the bins will be defined! To view the bin grid; Boom into a small area in the middle of the survey and depress the Display !ins button!
1%5
@ow that you have shot the survey and defined a bin grid; you can calculate the fold and midpoint attributes! Select Fold +alculation from the !in Analysis menu Analysis menu to open the I'old CalculationJ dialog! Choose the option option to calculate the the Fold7 O,,sets7 and A#imuths and press O;! O;! After the calculations finish; finish; the Fold Graph; Graph; O,,set Graph; Graph; A#imuth Graph; Graph; and 6oise Graph buttons; Graph buttons; on the in Attributes Attributes toolbar; become active! active! oom into an area of the survey and press these buttons to view the attributes!
11%5 After you are finished finished laying out and editing the survey; survey; the survey information information can be written to a variety of output output files! 7ne very useful format that that has industry:wide acceptance is the SE&:$, ASC"" ASC"" survey format! Dou can export the survey information to this format with the SEG/P1 option in the Output menu2 Output menu2
39
$ress the File button File button in the Source 'ile section and type IoutputYexer/,!srcJ at the I'ile @ameJ prompt; and select Save! Save! $ress the File button File button under the 9eceiver 'ile section and type IoutputYexer/,!rcvJ at the I'ile @ameJ prompt and select Save! Save! These two two files will will be used in later exercises! exercises! $ress O; to O; to create the files!
40
DO IT YOURSELF #1 'rom the File menu; File menu; select the 6e- Database option! Save your current current database when when prompted to do so! )ay out a survey using the following parameters2 9eceiver "nline Spacing2 9eceiver Crossline Spacing2 9eceivers $er )ine2 @umber of )ines2 9eceiver "nline earing2 9eceiver Crossline earing2 H:Coordinate of ,st 9e 9eceiver st D:Coordinate of , 9e 9eceiver
0/ m %// m (% ,, 4/ degrees / degrees /!/ /!/
Source "nline Spacing2 Source Crossline Spacing2 Sources $er )ine2 @umber of )ines2 Source "nline earing Source Crossline earing H:Coordinate of ,st So Source st D:Coordinate of , So Source
0/ m %// m (/ ,, / degrees 4/ degrees %0!/ %0!/
Save the survey with the name IbasicJ!
41
E=E2+*SE >& // .ine?!ric0 .ayout Options This exercise demonstrates some of the different layout options avaiable for line5bric6 layouts in MESA! Dou will be creating three surveys in this exercise! The first survey will be completely uniform and will use se-uential numberingV the second survey will have variable receiver line spacing and will be numbered with the grid based methodV the third survey will use slanted source lines! ,!= Start MESA; or select 6e- Database from the File menu if you have a survey already loaded in MESA! Dou will be creating a simple straight line orthogonal survey! Select 2eceivers I .ines?!ric0s from the .ayout menu! 'ill in the I)ine5ric6 )ayoutJ dialog as it appears below! $ress the 6umbering button to open the I@umberingJ dialog!
%!= A uni-ue identifying number is usually created by combining a line number with a number for the receiver or source! 'or example; if the first receiver line of a survey is called the ,/, line and the first receiver on that line is called 0/,; then the receiver point is called ,/,0/,! The next point on that line will be called ,/,0/%! "n the survey you are laying out; there will be * sources per source line between each receiver line! ecause of this; the receiver line numbering interval will increment by *; the ,/, line; the ,/+ line etcZ So the first receiver on the second receiver line will be ,/+0/,! The sources will start with )ine 0/, and the sources will start numbering with ,/,; so the first source is 0/,,/,! Since there will be 8 receivers per line between each source line; the source line will increment by 8; so the first source of the next line will be 0/4,/,! Survey @umbering can be done during source or receiver layout or by using the 2enumbering option in pull down menus from the source5receiver display buttons! @ormally numbering assumes a uniform spacing where you can supply a numbering system that will label every point in an ordered fashion! The numbering system can be
42
used to indicate spatial location; in addition to simply labeling the sources and receivers! Se-uential numbering wor6s fine as long as the survey is uniformly spaced! "f the survey has varying line spacing o r point intervals; se-uential numbering will not wor6 properly! &rid based numbering was developed for non:uniform surveys! 'ill in the I@umberingJ dialog as it appears below! The First 2eceiver field contains the full uni-ue identifying number for the first receiver! The 2eceiver *nc field contains the increment for numbering the next receiver in line! The 2eceiver .ine *nc field contains the increment for numbering the first receiver of the next line! MESA will determine what portion of the number is a )ine @umber with this increment! Dou can also specify a )ine @ame $refix or Suffix in this dialog! The )ine @ame will be created by ta6ing the )ine @umber and adding any prefix or suffix that is specified! @otice that you can define the numbering for both receivers and sources in this dialog! Dou only need to define the numbering for each once! Any sources or receivers that you lay out after setting the numbering will use the defined se-uential numbering scheme! 7nce you have filled in the I@umberingJ dialog; press O; in it and then press O; in the I)ine5ric6 )ayoutJ dialog to lay out the receivers! $ress the .abel Display?Options icon to display the receiver labels in the esign Gindow; as shown below!
43
3!= @ow lay out the sources! Select Sources I .ines?!ric0s from the .ayout menu! 'ill in the I)ine5ric6 )ayoutJ dialog as it appears below! Since you set the source numbering at the same time as the receivers; you do not need to o pen the I@umberingJ dialog again! isplay the labels once the sources are laid out and the esign G indow should appear the same as below! Save the survey as Iexercise/%YregularJ!
44
(!= The se-uential numbering system will not wor6 as reliably for the next survey! Dou will be laying out new receiver lines with variable spacing! 7pen the I)ine5ric6 )ayoutJ dialog for the receivers! 'ill out the dialog as it appears below! @otice that when you chec6 the 'se 3ar% +rossline Spacing option; the 3ariable button becomes active! $ress the button to open the IFariable Crossline SpacingsJ dialog! 'ill it in as shown and press O;! $ress the O; button in the I)ine5ric6 )ayoutJ dialog to lay out the receivers! Select 2emove when prompted to remove the existing receivers!
The survey will now have receiver line intervals of 3//; %//; and ,// instead of the uniform 3// and should appear as below! The line numbering won#t be able to increment by an even * as it did before since between any % ad?acent receiver lines there are either %; (; or * source points on any one given source line! "deally the goal would be to have line one be ,/,; line two be ,/+; line three be ,,,; line ( be ,,3; and line 0 be ,,4! This is not a se-uential se-uence!
45
0!= Gith the new receiver lines displayed; select 2enumbering : Grid !ased from the 2eceiver Display?Options button sub menu! &rid based numbering renumbers the survey by placing a user:defined grid on the survey and numbering that grid se-uentially! Anytime a receiver line or point occupies a part of the grid with a number associated with it; the point will get that number! The grid is given a reference number similar to the starting number in the uniform survey; ,/,0/,! The grid is defined so that it will occupy every possible location of a receiver line or point! "n this example the grid spacing is 0/ in both the inline and crossline direction since 0/ is the source spacing and we want to reflect the number of sources between each pair of receiver lines! The grid is defined to increment by , in the inline direction and by ,/// in the crossline direction! $ress Auto Fit to automatically fill in the &rid 9eference fields! 'ill in 0/ for both the *nline and +rossline Grid Spacings after you have performed the Auto Fit calculation! $ress O; after filling out the I&rid ased 9enumberingJ dialog as shown! MESA has now numbered a variable line spaced survey in the same reliable manner as that of a uniformly spaced survey! Select Save As 6e- Database from the File menu to save this survey under a new name! Save the survey as Iexercise/%YvariableJ!
46
*!= 'inally we will use the Slant option to create a survey with a slanted source layout! Select 6e- Database from the File menu! 'rom the .ayout menu; select 2eceivers; and then the .ines?!ric0s option! 'ill in the I)ine5ric6 )ayoutJ dialog as shown and clic6 on O;2
47
+!= @ext; use the .ines?!ric0s option to lay out the sources! 'ill in the dialog as follows! Ghen you chec6 the 'se Slant Parameters option; the Slant button is activated! $ress the button to open the ISlant )ayout $arametersJ dialog! Set = Moveup to ,,/; J Moveup to %%/; and .ine Spacing to ,3%/! $ress O; in both dialogs to lay out the sources!
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8!= Save the survey as Iexercise/%YslantJ! Dour survey should loo6 li6e this2
49
DO IT YOURSELF #2 'rom the File menu; select the 6e- Database option! Save your current database when prompted to do so! esign a survey with the following dimensions! The receiver and source numbering should match as in the exercise/%Yregular and variable surveys! .se ,/,0/, for the first receiver and 0/,,/, for the first source! Survey SiBe2
0mi x 0mi; <%*(//# x %*(//#=
9eceiver "nterval2 9eceiver )ine "nterval2 9eceiver )ine "nline earing 9eceiver )ine Crossline earing H:Coordinate of ,st 9eceiver D:Coordinate of ,st 9eceiver
%%/# ,,//# 4/ degrees / degrees */048(!// ,*004+(!//
Source "nterval2 Source )ine "nterval2 Source )ine "nline earing Source )ine Crossline earing H:Coordinate of ,st Source D:Coordinate of ,st Source ric6 $attern
%%/# 88/# / degrees 4/ degrees */08+(!// ,*0*/8(!// 0 sources5bric6; %:line repeat
in SiBe Shooting Template
,,/# x ,,/# ,% x +%
SAFE AS
multi,
50
E=E2+*SE >) // 'nit (emplate .ayout This exercise demonstrates how to use the 'nit (emplate option for laying out a 3: seismic survey! Dou will be creating a 3: survey in this exercise by filling a survey boundary! The survey will be a bric6 pattern that will be used later in the course! ,!=
Start MESA; or select 6e- Database from the File menu if you have a survey already loaded in MESA! Choose Edit Exclusions from the Exclusion Display?Options button submenu! This will open the Edit Exclusions toolbar2
%!=
Chec6 that the +reate Exclusion icon is selected! Choose the Survey !oundary icon from the possible exclusion types! Dou can 6eep the default @ame; if desired; but you must specify a )ayer for the exclusion! Select K@ew )ayerX in the layer list and create a layer called IoundariesJ!
3!=
@ext; clic6 on the De,ine Exclusion icon! The following dialog will appear2
@ote that you can specify the color; the infill pattern; and what will be excluded for the exclusion Bone in this dialog! Since you will be filling this boundary with sources and receivers; toggle off all of the options in the Exclude box! (!=
$ress Exclusion De,K; and enter the following H;D coordinates to define the survey boundary! 9emember to press the Add button after typing in each H;D coordinate pair! <*%%(8(; ,*+(*+(=; <*%%(8(; ,*4/0,(=; <*33/((; ,*4/0,(=; <*33/((; ,*80%3(=; <*383%(; ,*80%3(=; and <*383%(; ,*+(*+(= Exit the exclusion editing mode by selecting Edit Exclusions from the Exclusion Display?Options button submenu again!
51
0!=
52
Select 'nit (emplate from the .ayout menu! This will open the .nit Template window! $ress the .ayout (emplate icon to create your unit template! "t will as6 you to first set the grid siBe for use in laying out the template! Set the grid siBe to ,,/! After you set the grid siBe; the ITemplate )ayoutJ dialog is displayed! Enter the numbers as they appear in the dialog below! The template is a ,/ x *( patch; receiver interval %%/#; and receiver line interval 88/#! $ress Apply to layout the receivers! The sources need to be centered in the middle of the receivers! There is one line of ( sources that will be fired into each set of ,/ x *( receivers; and the sources have a %%/# interval! The starting coordinate centers the sources! $ress Apply under the Source )ayout section to add the sources to the template! Dou could continue to add or replace receivers or sources to create more complex templates! Select Exit to finish laying out the template!
*!=
7nce you you have have finished finished layin laying g out the the templat template; e; there there are are editing editing option options s available available in the the .nit Template Template toolbar! Dou Dou can add; move; or delete any of the sources or receivers! Dou Dou can also add; copy; move; or delete entire templates! templates! 'or this example the desired source source pattern is a ,3%/# source source line interval bric6ed at **/#! The template needs to be copied one time from its current location to a location 88/# in the vertical direction and **/# in the horiBontal direction! Select the Ma0e?+opy (emplate icon (emplate icon to open the ICopy [ Move 7ptionsJ dialog! Choose +opy (emplate and (emplate and set = to **/ and J and J to 88/! $ress O; to display the updated template!
+!=
At this this point point the templa template te can can be repeated repeated to to lay out and and shoot shoot the the survey survey!! Select Select the the Shoot Options icon Options icon from the .nit Template toolbar to open the I.nit Template 9epeatJ dialog! Enter the values as shown on the next next page! Dou Dou will be setting the siBe of the survey by filling the exclusion Bone that you defined at the beginning of this exercise! The Clipping section section sets how the survey siBe area is filled! filled! Clipping the 9eceivers5Sources means that the receivers and sources fill ?ust the defined area! Clipping the fold means that enough enough sources and receivers are added to provide full fold in the defined area! "n this example; you want to to have sources and receivers in the defined area only; so select +lip 2eceivers?Sources to !ounds! !ounds ! Supply ,3%/ for the which to repeat the unit unit template! The *nline and *nline and ,+*/ for the +rossline spacings +rossline spacings at which Template Template 9eference 9eferenc e $oint defines where to start the template layout! layout ! Dou Dou want to start the template from the corner of the the survey boundary! $ress the Select Point button to graphically set the starting starting point for laying out the templates! templates! ighlight the receiver receiver at <**//; 30%/= as the starting point and select the Shoot Options ic on again! again! $ress O;7 Options icon and the survey will be laid out and shot in the boundary!
53
The esign Gindow should now have a survey similar similar to the one below! below! This survey has a receiver interval of %%/# and a receiver line interval interval of 88/#! The source interval is %%/#; %%/#; and the source line interval is ,3%/# bric6ed at **/#; shot with with a ,/x*( template! Since the bin grid is placed automatically with this layout method; you can go immediately to the !in Analysis menu Analysis menu and select the Fold +alculation option to calculate the fold and midpoint attributes! Save this survey as Imulti%J! Dou will be using it again in a later exercise!
54
DO IT YOURSELF #3 'rom the File menu; File menu; select the 6e- Database option! Save your current current database when when prompted to do so! Select Edit Exclusions from the Exclusion Display?Options button submenu! $ress the 2ead Exclusion File button and load the exclusion file called called multi%!xcl! This loads the exclusion Bone from the multi% survey into the the new survey! Exit the edit mode by selecting selecting Edit Exclusions again! @ow use the .nit Template Template Gindow to lay out the survey! Create a template with the same parameters you used in Exercise 13! Dou will be creating an orthogonal survey this time; so you do not need to copy the the template! "nstead choose Move (emplate4s5 and (emplate4s5 and shift the H Coordinate by ,,/! "n the I.nit Template 9epeatJ dialog; choose Fill Polygon; Polygon ; +lip Fold to !ounds ; set *nline and +rossline Spacings to 88/; Auto/+alculate Auto/+alculate 2e,erence; 2e,erence; and set Speci,y .ine !earing to 4/! o not chec6 the option to 'se Full (emplates! (emplates ! This will layout layout a survey that has ?ust enough receivers and sources to generate full fold fold in the exclusion Bone! Select Fold +alculation from the !in Analysis menu to loo6 at the fold coverage! After you loo6 at the fold coverage; go go bac6 to the .nit .nit Templ Template ate Gindow and re:open re:open the J.nit Template Template 9epeatJ dialog! .se the same settings; but this time chec6 the option to 'se Full (emplates! (emplates! Also ma6e sure that that you chec6 2emove Existing Survey! Survey ! This will will remove the survey and then lay out a new survey! The new survey will still have full fold in the exclusion Bone; but now it has all of the receivers necessary for each source to have a full template! 7utput the survey information into SE&:$, files called IoutputYexer/3!srcJ and IoutputYexer/3!rcvJ!
55
E=E2+*SE > I (he Design Guide This exercise demonstrates the use of the esign &uide to aid in the layout of your survey! Dou will be defining an exclusion Bone and filling it with sources and receivers! Dou will use the esign &uide to determine the source and receiver spacings; bin grid siBe; and template siBe needed for your desired target parameters! 1%5
Start MESA or select 6e- Database from the File menu if MESA is already running! Create a new survey boundary exclusion Bone! .se the layer name IoundariesJ for this exclusion and give it the following coordinates2 <:0/; /=; <%(//; /=; <3%*/; ,04/=; <3/4/; %(+/=; <%(3/; %80/=; <,/0/; %4//=; and <:0/; ,0//=
After you have finished laying out the exclusion Bone; save the database as Iexercise/(J! "t should loo6 li6e this2
56
&%5
.nder the .ayout menu; select the Design Guide option! 'ill in the interval velocity at target; the dips; and the horiBon time for the Bone of interest; as shown in the following dialog2
@otice that the edit boxes in the (arget Parameters group box are tied to the fields in the !in Si#e group box; so changing information in one area automatically updates information in the other area! Max bin siBes are calculated for both inline and crossline dips! Change the bin siBe to %0 m in e ach dimension and the Max 9ecoverable 're- increases to ,/0!3! The following e-uation is used to 6eep the values in the (arget Parameters group box consistent with the values in the !in Si#e group box2 !in Si#e !in Si#e L "nt Felocity at Target 5 <(!/ Max 9ecoverable 're-uency sin <ip Angle== )%5
@ext; change the source and receiver intervals to be twice the bin siBe; or 0/ m! Dou can experiment with various line spacings; but choose %// m for both source and receiver line spacings! 3ertical 2esolution Estimate Fertical resolution is based upon the interval velocity at the target and the bandwidth of the recoverable fre-uencies! Minimum 3ertical 2esolution L "nt Felocity at Target 5 < (!/
57
.ateral 2esolution Estimate .ateral 2esolution L 3!/ Minimum Fertical 9esolution 5 sin
Clic6 the 3elocity Function button to open the IStretch Mute Time5Felocity $airsJ dialog! This dialog is used for entering time:velocity pairs and calculating a stretch mute! Change the Stretch Mute Percent to /!%0 and then enter the following time:velocity pairs; remembering to press Add after typing in each pair2 <*//; ,8//=; <,///; %(//=; <%///; 3///=; and <3///; 3*//=
"f you need to remove a time:velocity pair; select the pair in the list and then clic6 on the Delete button! "f you need to edit a pair; select the pair in the list; ma6e the appropriate changes in the Time or Felocity edits; and then select a different pair in the list to apply the changes! Clic6 on O; to save the changes to the stretch mute! The mute will be drawn in the Mute 'unctions window! This mute can be applied in the .imits options of any of the bin attribute displays!
58
B%5
@ext; press the +alc Mute O,,set button to bring up the following dialog2
The effects of the mute function can be seen for offsets in increments of ,// units! "n addition; the mute offset at the target is listed; along with the maximum minimum offset for the survey! Max Minimum O,,set
≅ <
RL2
+
SL2 = : SA
Ghere 9) is 9eceiver )ine Spacing; S) is Source )ine Spacing; and SA is the salvo ad?ustment! The salvo ad?ustment corrects the offset for sources not being concurrent with receivers! The ad?ustment is
@ext; clic6 on +alc (emplate Si#e%
59
@otice that spacings are given for the fold; and the max minimum offset is listed as well! "f you change the source line spacing; the receiver line spacing; or the number of channels; press +ompute (able to recalculate the data in the list box! Specify 38( as the 6umber o, +hannels; and clic6 on +ompute (able! ased upon the e-uation for 6ominal Desired Fold; the suggested line spacings for achieving this fold value
'irst; for the receivers2
'ill the polygon that you defined at the beginning of this exercise by selecting the Fill one option! Clic6 on O; to lay out the receivers!
60
%5
And; for the sources2
Again; choose the Fill one option to fill the exclusion Bone you defined! .nder Shi,t o, First Source; specify %0 for both the H and D values! This will offset the first source a distance of one:half a group interval from the starting receiver! .nder !ric0 Options; toggle on the !ric0 Pattern and enter ( Sources Per Group with a .ine 2epeat *nterval of %! Clic6 on O; to lay out the sources!
61
Save the survey! "t should loo6 li6e this2
62
E=E2+*SE >B // *mporting Survey Files This exercise shows how to import coordinate ASC"" files to layout a survey in MESA! The ASC"" files to be imported are the source and receiver SE&:$, files created from the Iexercise/,J survey in Exercise 1,! MESA can import data from any columnar ASC"" file type! ,!=
Dou will import the survey from the SE&:$, files! 'irst you will import the receivers! Select 2eceivers I File *mport from the .ayout menu! This opens the I9eceiver "mport SetupJ dialog! "f you are importing a standard file type; you can select the type from the list to automatically load the configuration file for it! Dou can also load your own configuration file if you have created one for the file you want to import! Dou can then use the Open Data File button to specify the file to load! The configuration file will then be used to import the data from that file! "n this case; you do not have a configuration file so you will have to manually define the data to import from our file!
%!=
$ress the *mport
63
3!=
The list box contains the variables to define from the data in the ASC"" file! Ghen you are initially importing points; you must specify at least )ine @umber or )ine @ame; 9eceiver or Source; H Coordinate; and D Coordinate! After you have the survey in MESA; you can update points by simply specifying 9eceiver or Source and the information that you wish to update! 'or this exercise you will be defining the )ine @umber; 9eceiver; H Coordinate; and D Coordinate! As )ine @umber appears first in the list box; begin by defining the columns that represent the )ine @umber! .se the mouse to highlight the range of columns for that parameter in the file! After the information is highlighted; press the De,ine (ype icon! "n the I'ormat efinition ialogJ; you specify the format of the variable and the decimal location and press O;%
(!=
After you have finished in the I'ormat efinition ialogJ; the information area of the "mport Gindow toolbar turns green and displays the information that you ?ust set! @ow is a good time to set the first line to import as well! Gith the )ine @umber columns still highlighted; press the Set First .ine icon! This opens a dialog where you tell MESA what the first line with data in the file is! The dialog opens with a default value of the line that is highlighted! "f you have highlighted something on the first data line; you can ?ust press O; to set that as the first line to import! 7therwise; you can type in the first line that you want to import and press O;!
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@ow that you have set the )ine @umber and the first line to import; select 9eceiver in the list! ighlight the last four digits of the receiver number
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The final things to set are the H and D Coordinates! 'or the H Coordinate; highlight %(+%/80/! The SE&:$, format has an implied decimal that must be added bac6 during the import into MESA! "n the I'ormat efinition ialogJ; change the type to ')7AT <7.)E=! "n the ecimal $oint section; press the LL button to move the decimal point one place to the left; ma6ing the H Coordinate %(+%/80!/! $ress O;! Choose D Coordinate; highlight *0%3+3//; and again change it to ')7AT <7.)E= and move the decimal point one place left!
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Dou can review what you have set by pressing the 2evie- +on,iguration icon! >eep pressing it to cycle through all of the items that you have defined! Dou can save these settings to a configuration file with the Save +on,iguration File icon! "f you have saved configuration files; you can load them with the .oad +on,iguration File icon! "f you did not want to import the entire file; you can use the Set .ast .ine icon to set the last line of data to import! The last line to import is the end of the file by default!
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7nce you are ready to import the file; press the Exit icon! MESA will as6 if you are ready to import the data! $ress Jes to continue with the importV $ress 6o to close the "mport Gindow without importing anythingV $ress +ancel to return to the "mport Gindow! Ghen you continue the import; the I"mport 7ptionsJ dialog opens! This dialog lets you remove or update existing records when you import! $ress the +ombination Options button! Since you defined a separate )ine @umber and 9eceiver; you must combine them to create the uni-ue 9eceiver number in MESA! e sure that +ombine .ine 6umber and 2eceiver 6umbers is chec6ed and that 2eceiver 6umber Digits is set to (! $ress O; here; and then press O; in the I"mport 7ptionsJ dialog! The receivers should now be imported and displayed in the esign G indow!
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Select Sources I File *mport from the .ayout menu and repeat the previous steps using the source file
DO IT YOURSELF #5 'rom the File menu; select the 6e- Database option! Save your current database as when prompted to do so! )oad the SE&:$, files you created in o "t Dourself 13! Save the survey as IfullfoldJ! Dou will be doing more with this survey in a later exercise!
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E=E2+*SE >C // Marine Design This exercise demonstrates the marine design capabilities of MESA! esigning marine surveys uses many of the same options as designing land surveys; including defining bins and calculating attributes! "t is possible to generate sail lines in the esign Gindow and view any of the fold; offset; and aBimuth attribute displays available in MESA! "n this exercise; you will create a marine sail polygon and a marine survey to fill the polygon! ,!=
The first thing to do is define a marine sail polygon exclusion Bone! efine the exclusion Bone ?ust as you did in Exercise 13; except use the !loc0 Polygon icon instead of the Survey !oundary icon! ere are the coordinates for the polygon2 $oint 1,2 $oint 1%2 $oint 132 $oint 1(2 $oint 102
<,////; /= <%////; /= <%////; ,////= <,////; %////=
Ghen you are finished; the exclusion Bone should be displayed in the esign G indow as it appears below! This exclusion Bone will be the boundary for your marine survey!
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7nce you have created the exclusion Bone to fill; select Marine Design
multi:boat configurations! "f you only have one boat; leave it at
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7nce you have finished setting up the boat configuration; select the 'nit +ell !inning icon to define the binning parameters! The I.nit Cell inningJ dialog is used to define parameters for binning a unit cell! The unit cell is a repeatable unit containing the bin attributes of the full fold area! The number of bins generated is larger than the actual Iunit cell;J but a sufficient number of bins is provided to create a diagnostic display! 'ill in the dialog as shown below! Select O; and the Marine Gindow will fill in accordingly! The current configuration and sail spacings will yield an ,8 fold survey!
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@ow you will use this boat configuration to generate a marine survey that fills the exclusion Bone you defined! Select the Sail .ines icon to open the ISail )ines 7ptionsJ dialog! 'ill in the dialog as it appears below! Dou are filling the exclusion Bone in this exercise; but it is
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also possible to ?ust fill a rectangular area! The )ine earing defaults to the longest distance across the defined area! Generate O,,lap extends the sail lines so that the area to fill is full fold! "f you do not generate offlap; the survey ends at the fill area boundary! Generate Sail .ines actually displays the marine survey in the main esign Gindow! "t is not necessary to generate the sail lines to perform unit cell bin analysis in the Marine esign Gindow! Select O; after filling in the dialog! The main esign Gindow will update with the marine survey inside the defined polygon! Dour window should appear as on the next page! oom into the northern most corner and hold down the Shift 6ey and )eft Clic6 on a source! The ISource "nformationJ dialog will be displayed! "f you loo6 in the esign Gindow; the source will be highlighted and the streamer positions for that source will be displayed!
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"n order to generate and view the diagnostics; you will now need to define a bin grid to fit the marine survey! Select !in Grid Settings from the Display !ins button submenu and fill in the Iin efinitionJ window as shown!
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Select the Fold +alculation option from the !in Analysis menu and calculate Fold7 O,,sets7 and A#imuths! 7nce the calculations are finished you can view all of the attribute plots for the marine survey! The fold plot should appear as it does below; showing ,8 fold throughout the area enclosed by the polygon! Toggle off the display of the source points to improve the visibility of the fold plot!
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E=E2+*SE > // 'sing GMG *mage This exercise explains how to use &M& "mage to prepare images for use in MESA! &M& "mage can be used to warp an image to fit a 6nown group of points; crop an image; and shift an image! "t can also merge together layer files to ma6e one image! "n this exercise; you will georeference a file by converting it to &M&#s image format! Dou will also use the warp tool to ad?ust an image! ,!=
Start &M&:"mage and select the (*FF option from the .oad submenu in the File menu! Select the Iimage!tifJ file and clic6 on Open! The ICoordinate EntryJ dialog allows you to position the image! This dialog is displayed if there is no georeference file with the image! Enter the following scale and coordinates for the image2
The HD coordinates correspond to the upper left corner of the image! Ghen the calculations are complete; the image will be displayed! 'eel free to Boom and pan to evaluate the -uality of the image! This image shows a variety of real world obstacles that will need to be accounted for in the survey design!
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Select the File menu and choose the Save .ayer File option! &ive the output file a name and press Save! The !lyr file extension will be appended automatically! The georeferencing information is now stored with the image so it will be correctly siBed and positioned when the )D9 file is opened in MESA!
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Select .oad/@!itmap from the File menu! )oad the Imap!bmpJ file! .se the defaults in the ICoordinate EntryJ dialog! This image needs to be warped so that the 6nown points are at the correct location!
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$ress the Add
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After the three warp points are set; select *mage/@
E=E2+*SE > // Source and 2eceiver Editing This exercise demonstrates some of the editing tools available in MESA to change your surveys! Dou will import an image to use as a bac6ground! 7nce the survey is set up with the image as the bac6ground; the receiver and source editing tools can be used to move points2 singularly; line by line; or as a group! Creation and editing of exclusion Bones can also be aided by the use of images in the bac6ground! ,!=
Start MESA! & o to the .ayer Display?Options button submenu and select the .oad I GMG .ayer option! )oad the Iimage!lyrJ file that was created in &M& "mage in the previous exercise!
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Select Open Database from the File menu and open Iexercise/0J! )oaded images remain loaded when you open or close surveys! Dou can unload images by selecting 'nload from the .ayer Display?Options button submenu! )oo6 at the first receiver line! There is a road on the image that runs near the first receiver! The road is at a different angle than the receiver line! )et#s assume that you actually wanted the survey to be parallel to that road! Dou can use the 9ange earing tool to determine the difference in the angles! Dou can then use the Translation59otation tool to move the survey to the new position!
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$ress the 2ange !earing tool button! "f you clic6 and hold down the )eft Mouse button; you can draw range bearing lines! old down the Ctrl 6ey when you draw the lines to snap the start and end points of the line to the nearest records! oom in on the road a bit; clic6 near the center of the road by the first receiver; and then drag and release the button in the center of the road further along! Dou should see that the bearing is about ,3,!*! old down the Ctrl 6ey and clic6 on the first receiver! rag and release the button on another receiver in the line! Dou should see that that the receiver line bearing is about ,34!+! This means you need to ad?ust the survey by :8!, degrees to have the receiver lines parallel to that road! $ress the 2ange !earing tool button again to turn off the tool! Select +lear All from the button submenu to remove the lines from the display!
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Select (ranslation from the 'tilities menu! Choose Speci,y !oth in the +oordinate 2otation section! $ut :8!, in the 2otation Angle box! Ma6e sure that both 2eceivers and Sources are chec6ed and press O;! The survey should be rotated so that the first receiver line is parallel to the road!
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@ow you want to redefine the third source line so that it follows the road that is displayed behind it! Select Edit Sources from the Source Display?Options button submenu! Choose .ine Selection Mode and 2ede,ine .ine! Clic6 on the road where you want the line to start; and then clic6 out several points along the road! ouble clic6 to finish adding points and the source line will be redefined to follow the points you chose! Select Edit Sources again to exit Source Editing mode!
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'inally; the last seven receivers on the first receiver line are too close to the housing development! Dou will use the esign &rid; the Move command; and the Snap command to accurately reposition those receivers! Select Edit 2eceivers from the 2eceiver Display?Options button submenu! $ress the Design Grid button! $ress Auto,it! Change the grid siBes to 00 by 00! Chec6 Display Design Grid and press O;! ide the image from the display in order to more easily see the design grid!
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Choose Group Selection Mode and Move! raw a polygon around the seven receivers and move the polygon to the intersections ?ust above the first source! ouble clic6 to place the seven receivers!
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Dou can now use the Snap function to position the receivers precisely! Choose 2ecord Selection Mode and Snap! Dou may have to use the Move function to get the receivers closer to the correct intersections! Dou could also set the Snap Options so that the receivers automatically snap to the nearest intersection after each move! Select Save As 6e- Database from the File menu and save the survey as Iexercise/8J!
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E=E2+*SE >H // O,,set 4+ircular5 and 2ectangular Shooting This exercise demonstrates the 7ffset
Start MESA and select Open from the File menu! 7pen the survey Iexercise/0J! $ress the Shoot button on the Edit toolbar to open the IShootJ dialog!
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O,,set Shooting uses absolute offsets to determine the live receiver patch for a source! $ress the O,,set Options button to set the offsets! "f a Minimum O,,set is specified; the template is ring shaped instead of simply circular! 'ill in the dialog as shown and press the O; button! $ress the Shoot button to actually shoot the survey! The esign Gindow will update to show each source being fired along with the template being used! .se the 6eyboard shortcuts from page %( to speed up or pause the shooting!
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Ghen shooting is finished; the next step should always be examing the templates that were created! Select Edit (emplates from the 'tilities menu! Ghile in (emplate Selection mode; left clic6 on a source to display the receiver patch for that source! All of the sources that fired into that patch will be highlighted! .se the arrow 6eys on the 6eyboard to step through all of the templates! Ghen you are finished loo6ing at the templates; select Edit (emplates from the 'tilities menu again to exit the edit mode!
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$ress the Shoot button again! The template list is now filled with the templates created by the 7ffset Shooting! e careful about removing templates from this list! "f a template is removed without unshooting the survey; all of the sources still loo6 li6e they have been fired; but some of the sources will no longer have associated receiver patches! $ress the 'nshoot Survey button to return the sources to their unfired state! @ow that the survey is unfired; it is safe to press the Delete All button and remove all of those templates!
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Select 2ectangular Shooting and press the 2ect Options button! This will open the I9ectangular 7ptionsJ dialog! 9ectangular Shooting wor6s li6e 7ffset Shooting but it uses a rectangular region around the source instead of a circular template! The !earing Dimension is the length of the rectangle along the specified bearing! The +ross/!earing Dimension is the length of the rectangle perpendicular to the specified bearing! The rectangle is centered around each source and all of the receivers within this area are included in the receiver patch for that source! 'ill in the dialog as shown and press O;! $ress the Shoot button to shoot the survey again! )oo6 at the resulting templates with Edit (emplates!
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9eturn to the IShootJ dialog; unshoot the survey; and delete all of the templates again! Select O,,set Shooting once more; but this time unchec6 the Fire All Sources option! $ress the Shoot button! "nstead of beginning to shoot the survey; MESA prompts you to select a starting source! Clic6 on the source at %(+(%3*!%/; *0%33,+!*/! This is the ,3th source on the 3rd source line! $ress the Shoot button on the Edit toolbar to open the IAuto:Shoot )imitsJ dialog!
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The IAuto:Shoot )imitsJ dialog is used to specify a subset of the survey area for shooting! "n this case; the limits will only affect the sources! The receivers portion is used to limit roll on5off with other shooting methods! The values in the edit boxes correspond to MESAs logical ordering of sources and receivers and not the point label numbering! 'ill in the source limits as shown and push the Shoot button! Shooting will then commence for the specified area! The survey should appear as shown!
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E=E2+*SE >1 // Automatic (emplate +entering This exercise demonstrates the Automatic Template Centering shooting method! Automatic Template Centering is the most commonly used shooting method in MESA! 'or this method; the closest receiver to a source point is located and used as a centering point for the entire template! "t is also possible to s6ew the template from the center by using the Template S6ewing ialog! S6ewing can be used to perform off:end shooting geometries! ,!=
Start MESA; if necessary; and select Open from the File menu! 7pen the survey IbasicJ! $ress the Shoot button to open the Shoot dialog!
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A template must be defined to use Automatic Template Centering! $ress the +reate (emplate button! The template defines the siBe of the receiver patch that is active for shooting! "n Automatic Template Centering; this template is centered around each source! 'ill in the 6umber o, .ines and 2eceivers Per .ine values as shown and press O;! The template should be automatically selected in the template list and Automatic (emplate +entering should be the selected shooting method! Ferify that the (emplate 2oll On?O,, and Fire All Sources options are both chec6ed! $ress the Shoot button to shoot the survey!
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Select Edit (emplates from the 'tilities menu and loo6 at the shooting results! ecause this survey is idealiBed and has the sources perpendicular to the receiver lines; all of the sources in a line between two receiver lines have the same centering position; so they are all fired into the same receiver patch! "f the sources did not line up; they would have different receiver patches!
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"t is also possible to s6ew the template so that the sources are not in the center of it! &o bac6 into the Shoot dialog and unshoot the survey! $ress the Auto+enter Options button! The resulting dialog is used to specify the s6ew in terms of number of receivers and number of receiver lines! 'ill it in as shown; press O;; press Shoot; and then loo6 at the results in the Edit (emplates mode!
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"n both of the previous shooting cases; the receiver patch has rolled on and off the edge of the survey! The amount of roll on5off can be changed if necessary! .nshoot the survey and reset the s6ew parameters to / and /! .nchec6 the (emplate 2oll On?O,, option and press Shoot! MESA brings up the Auto:Shoot )imits dialog! This dialog is used to set the ranges where the receiver patch stops rolling! $ress the Survey Edges button to fill in the dialog with the full extents of the survey! This will cause the receiver patch to stop rolling when it reaches the edges of the survey! $ress the Shoot button to shoot the survey!
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$ress the Open Database button and load the Iexercise/(J survey! .sing the template from the Design Guide; shoot this survey with Automatic (emplate +entering; ma6ing sure to Fire All Sources and 2oll (emplate On?O,, ! )oo6 at the results in the Edit (emplates mode! The template loo6s good in the lower half of the survey; but it is not correct in the upper half! The problem is that the template is positioned by using the internal se-uential numbering! Since the starting position of the receiver lines changes; the se-uentially numbered receivers do not line up! There would be a similar problem if there were gaps of missing receivers in the middle of the lines! The full number of receivers for each line would still be in the template regardless of the gaps! The position of the last receiver on each receiver line will not affect the template positioning if the template is rolling off the survey!
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The Shooting Grid option is used to correct the template positioning in surveys with irregular starting postions or gaps in the middle of receiver lines! 9eturn to the Shoot dialog and unshoot the survey! Select Automatic (emplate +entering as the shooting method and toggle on the option to 'se Shooting Grid at the lower right! The Shooting Grid option will impose a grid on the receivers which will compensate for the irregular shape of the survey! The shooting grid should automatically have default values that will wor6 well for the survey! "t is also possible to manually define the shooting grid for greater control! Clic6 on the Grid button to open the Shooting &rid dialog! $ress the Auto Fit button to set the values in the dialog as shown! $ress the O; button to close the dialog; and then press the Shoot button to shoot the survey! )oo6 at the results in Edit (emplates mode! The receiver templates should be the same throughout the entire survey area!
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E=E2+*SE >11 // Salvo Shooting This exercise shows the Salvo shooting method! Salvo shooting handles scenarios of multi: source salvos that span receiver lines and salvos that re-uire restricting the inline template roll! Salvo shooting is very well suited for slant geometries and bottom:cable designs! "n our terminology; a salvo is a set of source points
Start MESA; if necessary; and select Open from the File menu! 7pen the survey Iexercise/%YslantJ! $ress the Shoot button to open the IShootJ dialog!
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Create a ,/H+% template and use Salvo Shooting! $ress Shoot to set the salvos! Clic6 on a source in the center of the survey area! Salvo shooting ta6es all of the sources on that line between two receiver lines and shoots them into the same template! Dou can select several salvos and the receiver template will automatically ad?ust to be centered between all of the selected salvos! Clic6 on a salvo again to remove it from the template! Experiment for a bit with selecting salvos to see how the template changes! 'or this example; ?ust select one salvo for the template!
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The template is centered around the selected salvos by default! "t is also possible to s6ew the template so that it is no longer centered! $ress the arrow 6eys on the 6eyboard to move the template around! The green instruction bar at the bottom of the esign Gindow will update with the amount of s6ew in terms of receivers and lines! Try moving the template around! 9eturn the template to the original; centered position when finished!
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.nselect the Shoot icon to finish selecting salvos and to open the ISalvo 9ollJ dialog! The roll parameters are used to specify which sources are fired! A value of % for Source .ine 2oll would fire every other line of sources; starting with the selected sources! A value of % for 2eceiver .ine 2oll would fire every other row of sources; again starting with the selected sources! The default values of , and , shoot the entire survey! The Auto:Shoot )imits wor6 the same as in the other shooting methods and can be used to further limit the sources and receivers used! 'or this example; use the defaults of , and , and do not set and Auto:Shoot )imits! $ress Shoot to shoot the survey!
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As always when shooting; examine the results with Edit (emplates from the 'tilities menu!
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E=E2+*SE >1& // .abel Shooting This exercise demonstrates the )abel Shooting method! )abel Shooting shoots surveys using the labeling numbers; not the internal numbering! "t is convenient for shooting geometries which have a large number of sources shooting into a receiver patch
Start MESA; if necessary; and select Open from the File menu! 7pen the survey IbasicJ! efore using )abel Shooting; it is very important to 6now the numbering scheme of the survey and to 6now the numbers of the initial template location! "n this case; a template in the bottom left corner of the survey area will be used for the initial setup! The template will use sources (///0 to (///8 and receivers ,///% to ,//%0; %///% to %//%0; 3///% to 3//%0; and (///% to (//%0!
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$ress the Shoot button on the Edit toolbar! .nshoot the survey and delete all of the templates; if necessary! $ress the +reate (emplate button and ma6e a template of ( lines by %( receivers per line! Select .abel Shooting and press the Shoot button! This will open the I)abel @umber ShootingJ dialog!
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The J)abel @umber ShootingJ dialog has two parts! The spreadsheet is used to specify the initial template and also to display the updated positions as the template rolls! The 2oll Parameters section is used to control how the template rolls! 'ill in the template spreadsheet with the values from step , for the initial template! As the 'rom and To columns are filled; the esign G indow updates to show the specified sources a nd receivers! Ghen finished; the esign Gindow should appear as shown!
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After the initial template is correctly entered into the spreadsheet; the 2oll Parameters are used to roll the template! The values in the 2oll Parameters fields are added or subtracted; depending on the direction of movement; from the numbers in the spreadsheet! "f the new values correspond to numbers in the survey; those sources and receivers are used for the new template! "f the numbers do not correspond; the process is repeated! This occurs until the entire survey has been shot! The Previe- buttons are used to chec6 the 2oll Parameters! $ress the 'p Arro- button and observe the results to the spreadsheet and in the esign Gindow!
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7bviously the default roll parameters are not going to wor6 in this case! The sources shift by , location and the receivers shift by , line! 9ecall that the numbering scheme for this survey has the numbering increase by , in the inline direction for the sources and by */// in the crossline direction for the receivers! 'or this template; the roll should move the template up to the next group of ( sources and ?ust , receiver line up! 7nly the original template can be edited; press the ome button to return to it and then change the Source Points to (! )eave the 2ec .ine 2oll as ,////; since this is correct! $ress the 'p Arrobutton again to observe the change!
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$ress the ome button again to return to the first template position! @ow try pressing the 2ight Arro- button! Again the default parameters are not correct! This time the template needs to move crossline with regards to the sources and inline with regards to the receivers! The numbering for receivers increases by , inline and there are ( receivers between source lines! The number for sources increases by ,//// between source lines! "n this case; change the 2ec Points to ( and leave Source .ine 2oll as ,////! The template should now roll correctly when you press the 2ight Arro- button! "t is a good idea to roll the template several times in the different directions to chec6 that everything is set correctly!
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The 'se source limits option can be used to specify the sources to shoot instead of simply shooting the entire survey! "n this case; leave the 'se source limits option unchec6ed and press the Shoot button to shoot the survey! As always; examine the results with Edit (emplates from the 'tilities menu!
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DO IT YOURSELF #12 7pen the Iexercise/%YregularJ survey! Try to shoot this survey with label shooting! The template should have ( lines of receivers and 3% receivers per line! There will be * sources in each template! Ghen you have finished shooting the survey; loo6 at the results with Edit (emplates from the 'tilities menu! The templates should appear as shown!
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E=E2+*SE >1) // Multi/Survey +apability This exercise shows how to load multiple surveys in one MESA session! "n areas where existing 3: survey information exists; you can import those surveys and build designs that merge or Bipper your current survey designs with the pre:existing ones! Dou will be importing two 3: surveys for exercise 1,3! The surveys are Imulti,J; which was created in the Io "t DourselfJ section of Exercise 1,; and Imulti%J; which was created in Exercise 13! After importing both surveys; you will calculate three fold plots2 a plot showing the new fold for multi,; a plot of the new fold for multi%; and a combined fold plot for both multi, and multi%! ,!=
Start MESA; if necessary and Open Database from the File menu! 7pen the survey you created in Exercise 1, called multi,! Fiew the fold by pressing the Fold Graph icon to ma6e sure that all the fold calculations still exist!
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&o bac6 to the File menu; select the Multi Database option; and under this option select .oad! 'nload and Select will become active once multiple surveys are loaded in the esign Gindow! 7pen the survey you created in Exercise 13 called multi %! Dour esign Gindow should loo6 li6e the following!
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@otice that the title of the active survey is in the esign Gindow title bar! 9ight now the active survey is multi,! "f you display the fold now; it will show you the fold plot for multi,! )eave the fold displayed in the design window! .nder the File menu; select the Multi Database option again and choose Select! This will bring up the ISelect atabaseJ dialog that allows you to choose which of the loaded databases is active! Choose multi% and select O;! The esign Gindow is now showing both geometries but only the fold of multi%!
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The idea of having a multiple database survey is to show how the a ttributes of one survey will affect the other!
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'irst you will loo6 at how multi% will affect the fold of multi,! Ma6e multi, the active database again! 7pen the Display !ins button submenu and select !in Grid Settings to open the Iin efinitionJ dialog! @otice that the Fit (o Multiple Databases chec6 box is now active! 'or this calculation though; you only want the bin grid to cover the active survey; so leave the Fit to Multiple Databases option unchec6ed! $ress the Auto Fit button and then press O;! Fiew the new bin grid in the esign Gindow to chec6 that the bins only cover the multi, survey!
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7nce your esign Gindow appears as above; open the !in Analysis menu and choose the Fold +alculation option! "n this window select Fold7 O,,sets7 and A#imuths in the Calculation 7ptions section! "n order to calculate the fold with the influence of multi%; you must create a named calculation! Chec6 the 6amed Fold +alculation chec6 box
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o the same procedure now for multi%! .nselect the Fold Graph icon to remove the fold plot from the display! .nder the File menu; select Multi Database and choose the Select option! Ma6e multi% the active survey! Select !in Grid Settings from the Display !ins button submenu and in the Iin efinitionJ dialog perform another Auto Fit; this time for multi%! Do not toggle on the Fit to Multiple Databases checkbox! Select O; and display the bins in the esign Gindow! The esign Gindow should be similar to the window below!
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7pen the !in Analysis menu and choose the Fold +alculation option! "n this dialog select Fold7 O,,sets7 and A#imuths for the Calculation 7ptions! "n order to calculate the fold with the influence of multi,; you must create a named calculation! Chec6 the 6amed Fold +alculation chec6 box
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MESA can also calculate the fold for the entire multi database area including the overlap region between multi, and multi%! 7pen the Display !ins button submenu and select !in Grid Settings! "n the in efinition dialog; chec6 the Fit to Multiple Databases option! After chec6ing this option; press Auto Fit and select O;! The esign Gindow should appear as below!
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7pen the !in Analysis menu and choose the Fold +alculation option! "n this dialog select Fold7 O,,sets7 and A#imuths for the Calculation 7ptions! "n order to calculate the total fold for multi, and multi%; you must create a named calculation! Chec6 the 6amed Fold +alculation chec6 box
DO IT YOURSELF #13
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Ma6e multi, the active database! 9edefine the bin grid so that it does not use multiple databases! Select Fold Deletion from the !in Analysis menu and Delete All of the named fold calculations that you created! @ow create two new named fold calculations2 one that uses ?ust multi, and one that uses multi, and multi%! Select Fold +ompare from the !in Analysis menu! 'old compare creates a color plot of the difference between two fold calculations! Compare the fold for multi, and multi% with the fold for ?ust multi,! Toggle on the Fold Graph button to display the difference plot! @ow you can see exactly how much fold is added by the overlap area! The fold comparison is also very useful for comparing an ideal survey plan against the actual production data! This will be demonstrated in a later exercise!
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E=E2+*SE >1 // 'sing Advisor This exercise demonstrates some of the functionality of the Advisor menu! This menu is not available in MESA 'ield! ,!=
'rom the File menu; select the Open Database option and open multi,!mas!
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'rom the Advisor menu; choose the Aperture Modeling option! The following toolbar will appear2
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Select the Add Model (arget icon and clic6 on the survey to position a target! The target position can be ad?usted in the parameters dialog to precisely place the target! After you clic6 on the survey; the ITarget $arametersJ dialog will appear! Set the parameters as pictured! Ghen you clic6 O;; the target will be displayed as a red s-uare in the esign Gindow! Clic6 on the survey and add a second target with the pictured parameters!
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@ext; select the Add Segment button and clic6 on the active target
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@ow you you need to add segments segments to to the first first target target as as well! well! Dou need to to ma6e the first first target target the active target to add segments to it! $ress the Select (arget button and then clic6 on the first target! Select the Add Segment icon Segment icon again and define two segments for the target!
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Dour our esi esign gn Gindow Gindow should should now loo6 loo6 li6e li6e this2 this2
The blue outline defines the full:fold full:fold migration aperture! "n other words; you need to have full fold in this region if you desire to ade-uately image your target region! +!=
$lotting $lotting the the fold fold in the the design design window window indicat indicates es that this region region extends extends out of of the full full fold fold area! Dou would need to extend extend the survey to the east to fully image the target target area in this case!
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E=E2+*SE >1B // Attributes and Filtering This exercise demonstrates how to add attributes to a survey and how to filter a survey based on those attributes! Attributes Attributes can be integers or floating point numbers and are associated with either receivers or sources! The only limit to the number number of attributes that you can add to a survey is the amount of physical memory memory <9AM= on your machine! 'ilters allow you you to define subsets of source and receiver points within within your survey design! y filtering based on attribute attribute values; you can design very complicated surveys that span ac-uisition environments and use multiple types of e-uipment! Dou Dou will be creating a generic transition Bone survey in this example! $art of the survey area will be declared water with an attribute! Dou will then shoot the survey with two different templates templates for the water or land areas!
,!= ,!= Selec electt Open Database from the File menu and load Ifullfold!masJ; Ifullfold!masJ; the survey you created in o "t Dourself Dourself 10! 7pen the Edit Exclusions toolbar! Exclusions toolbar! %!= %!= Choo Choose se the the Polygon icon to create a regular regular polygon Bone! Create a polygon with with the following coordinates2 <*3*,%/; ,*4*8//=; <*3*,%/; ,**4/+/=; <*(4///; ,**4/+/=; <*(4///; ,*4*8//= The polygon should be displayed on the survey2
3!= Dou Dou are now ready to start adding attributes to the survey! survey! Select Add?2emove Attributes from the Attribute 3isibility and Options button submenu!
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(!= @otice the tabs in this dialog! Dou can create attributes for either sources or receivers by selecting the appropriate tab! 'irst; create a source attribute! $ress the Add button! This opens the IAdd AttributeJ dialog! Dou give the attribute a name and choose its type in this dialog! @ame the attribute IwaterJ and ma6e it an integer! $ress O;! The attribute will be listed in the source attributes! @ow switch to the 2eceiver Attributes tab and create the same attribute for the receivers!
0!= $ress O; to return to the esign Gindow! Dou have now added an attribute to the sources and the receivers! Dou still need to assign values to the attributeV this can be accomplished in several different ways! Dou can use the "mport Gindow to import values from an ASC"" file; manually enter values in the spreadsheets; identify a point
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+!= Scroll down through the spreadsheet until you find the H Coordinates larger than *3*,%/
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8!= @ow you need to set the attribute value for the sources! Dou will use the exclusion Bone tool to do this! Select Edit Sources from the Source Display?Options button submenu! This opens the Edit Sources toolbar! $ress the Exclusion Attribute Mode button!
4!= The first time you press this button; the IExclusion 9ecord Attribute SettingsJ dialog opens! Dou use this dialog to define the attribute and the value to give it! Dou also choose to set the value either by manually selecting exclusion Bones or by automatically setting the value for all exclusion Bones in a layer! Choose the option to Select Exclusions Manually; find water in the Attribute list; and set the 3alue to ,! $ress O; to go to the esign Gindow to select the exclusion Bone! Clic6 on the exclusion Bone that you defined! The exclusion should -uic6ly flash to indicate that it was selected and that all of the sources in the Bone now have a water attribute of ,! Dou can now ma6e a filter to chec6 the attribute settings! Select Edit Sources from the Source Display?Options button submenu to exit source editing mode!
,/!=Select Filter Options from the 2ecord Filter and Filter Options button submenu! The filter dialog defines what sources and receivers are displayed! Dou construct a filter by combining comparison statements! Any source or receiver that passes the filter settings is displayedV all of the other sources or receivers are hidden from the display! 7nly the visible sources and receivers are used for any program functions! Shooting; bin attribute calculations; data output; statistics; etc! only use the unfiltered points! This feature provides tremendous flexibility; particularly on complicated survey designs with different shooting templates; different 6inds of the e-uipment; and different terrains! ,,!=Dou want to filter the survey to show you ?ust the sources and receivers that have a water value of ,! This way you can chec6 that all of the points in the exclusion Bone were updated correctly! 'or the Source Filters; find water in the list of items to filter; choose *s E9ual (o from the comparison statements list; and put a value of , in the value box! $ress the Add button to add the statement to the filter list! Dou could continue to add statements to the filter list to ma6e a more complex filter! "f you select logical A6D ,ilters; all of the statements have to be true for the source to be displayed! Select logical O2 ,ilters to display sources that are true for any of the statements in the list!
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,%!=Switch to the 2eceiver Filters tab and create the same comparison statement! The receiver and source filters are entirely independent; so you can have completely different filtering criteria for your sources and receivers! $ress O; once you have the filters set!
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,3!=Toggle the 2ecord Filter and Filter Options button in the esign Gindow to apply or remove the filter! @otice that the filter parameters are displayed in the legend so that you can see exactly what is being displayed! Dou should only have the sources and receivers in the exclusion Bone displayed when the filter is applied!
,(!=9eturn to the filter dialog and switch the filter settings! Change the comparison to 6O( E:'A.S and press the 'pdate button! This will update the statement in the list with the new comparison! Dou can also 2emove the existing statement and Add a new one! Change both the source filter and the receiver filter to water 6O( E:'A.S ,!
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,0!=Dou can now use the filtered survey to shoot a template that changes as it rolls into the filtered area! "n Exercise 13; you shot this survey with a ,/ by *( template! Dou want to use this template again on the displayed part; but you will use a different template for the water points! Assume you do not want the ,/ by *( template to use the water points! $ress the Shoot button! ,*!=Create a ,/ line by *( receivers per line template! Choose Automatic (emplate +entering and press Shoot to shoot the survey! Toggle off the filter so that the entire survey is displayed and chec6 your templates with Edit (emplates from the 'tilities menu! @otice that only the displayed sources were fired and that the templates only use the displayed receivers!
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,+!=@ow you want to shoot the water sources! Assume that you want to use the non water receivers in the templates for the water sources! Additionally assume that you want to have ( receiver lines live in the water; but ,/ lines live on land! .pdate the source filter so that water E:'A.S ,; but leave the receiver filter as it is! Toggle the filter on!
,8!= $ress the Shoot button! Choose the ,/x*( template and Automatic (emplate +entering again! Chec6 the 'se .ine Filters option and press the .ine Filters button! The I)ine 'ilteringJ dialog allows you to honor or override the filtering for each line in a template! All lines honor filtering by default! Since you want to have ( lines live in the water area; you need to choose segments (; 0; *; and + and set each of them to override the filter settings! $ress O; in the I)ine 'ilteringJ dialog and press Shoot to shoot the water sources!
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,4!=Turn off the filter and loo6 at the templates with Edit (emplates again! @otice that the water sources have templates with ,/ lines of non:water receivers and ( lines of water ones! Save the changes to the database!
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DO IT YOURSELF #15 Try several different operations with the filter on and off to see the differences! Turn the filter on and loo6 at the .and Survey Statistics or perform +ost Analysis! @ow try them with the filter off! .nshoot the land portion of the survey without affecting the water sources
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E=E2+*SE >1C // Displaying Data This exercise shows how to display different types of data in MESA! Dou will be using secondary coordinates; fold difference plots; and attribute plots! ,!= Select Open Database from the File menu and load Ifullfold!masJ; the survey you used in Exercise 1,0! The water attribute should still be set for the part of the survey in the exclusion Bone! %!= 'irst; you want to use the secondary coordinates feature to store the initial survey coordinates! Every source and receiver point now has a primary H; D and; coordinate and a secondary H; D; and coordinate associated with it! The primary coordinate is the displayed coordinate! The secondary coordinate simply allows you to store another coordinate position for each point! Dou can use the secondary coordinate to store the initial idealiBed survey coordinates; and have the actual real world positions in the primary coordinates! Dou can then swap the two positions to see the differences! 3!= Select Secondary +oordinates from the 'tilities menu! This opens the ISecondary Coordinates 7ptionsJ dialog! This dialog is used to change or update the coordinates! Choose Store Primary +oordinates as Secondary +oordinates ! This feature copies the primary coordinates into the secondary coordinates; essentially creating a bac6up copy of the primary coordinates! Dou want to store !oth 2eceiver and Source +oordinates ! $ress O; to store the coordinates!
@ow that you have stored the coordinates; you can 2estore Primary +oordinates ,rom Secondary +oordinates to copy the secondary coordinates bac6 into the primary coordinates! Dou can also S-ap Primary and Secondary +oordinates to simply swap the primary and secondary coordinates without overwriting each other! Select +hange Display Options to activate the Display +oordinate Di,,erence 3ectors option! Ghen this option is chec6ed; vectors are drawn in the esign Gindow to show the difference in position between the primary and secondary coordinates!
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(!= Select 2andomi#er from the 'tilities menu! This function randomiBes the positions of sources and receivers by moving them to a random point within a limited distance from their original position! Set the options in the I9andomiBe CoordinatesJ dialog as shown! This can be used to simulate the randomness of a real world survey!
0!= 7pen the ISecondary Coordinates 7ptionsJ dialog again! Select +hange Display Options and then chec6 Display +oordinate Di,,erence 3ectors! The Minimum Di,,erence to Display field lets you limit the vectors that are displayed! MESA will only display vectors that are larger than the minimum you specify! So if you only want to see vectors for points that moved more than %0 units; put a %0 in for the minimum difference! 'or now; simply leave the minimum as /; this will display vectors for every point! $ress O; and Boom in on the esign Gindow! Dou will see the vectors displayedV the end of the vector is the position of the secondary coordinate for that point!
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*!= Try swapping the primary and secondary coordinates a few times! Dou might try swapping ?ust sources or ?ust receivers as well! 'inish by swapping the original idealiBed survey bac6 into the primary coordinates! Turn off the vector display by unchec6ing the Display +oordinate Di,,erence 3ectors option! +!= efine a ,,/ by ,,/ bin grid for the survey! Select Fold +alculation from the !in Analysis menu! Calculate Fold7 O,,sets7 and A#imuths to a named fold calculation titled Ifullfold O ideal O 'ull ataJ!
8!= Swap the primary and secondary coordinates again so that the randomiBed survey is displayed! Select Fold +alculation and create a named fold calculation titled Ifullfold O random O 'ull ataJ!
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4!= @ow you can compare the two named fold calculations to generate a fold difference plot! The fold difference plot lets you easily see areas where the randomiBed survey positions greatly change the fold distribution! Select Fold +ompare from the !in Analysis menu! Compare Ifullfold O random O 'ull ataJ to Ifullfold O ideal O 'ull ataJ! @ame the fold difference plot I'old differenceJ! $ress O; to generate the fold difference plot!
,/!=Toggle the Fold Graph button on to display the fold difference plot in the esign G indow! Dou may need to Boom in and toggle off the display of the sources and receivers to better see the difference plot! Dou can switch to a different fold calculation to display by using the Fold Selection option in the !in Analysis menu! Ghen you are done loo6ing at the fold displays; swap the ideal coordinates bac6 into the primary coordinates!
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,,!=Attributes can be displayed in the esign Gindow with color plots as well! 7pen the 2eceiver Spreadsheet from the .ayout menu! )eft:Clic6 on the Coordinate column header to highlight the entire column! 9ight:Clic6 on the highlighted cells to open the edit menu and select Formula!
,%!=Dou can use the I'ormulaJ dialog to fill cells in the spreadsheet with information from other cells! "n this case; you want to create a Coordinate by subtracting off a large portion of the H Coordinate! Select H Coordinate from the Database 3ariables list! "t will be automatically added to the Formula! $ress the I button and then choose Secondary H from the list! This will subtract each row#s $rimary and Secondary H Coordinates and then the result of this calculation will be put into the Coordinate cell!
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,3!=@ow you can display the color plot for Elevation in the esign Gindow! Close the 9eceiver Spreadsheet! Select Attribute Display from the Attribute 3isibility and Options button submenu! The IAttribute isplayJ dialog is used to choose the attributes to display! Dou can display a source attribute; a receiver attribute; or both! 'or this example; leave the source attribute as @one and set the receiver attribute to Elevation! $ress O;!
,(!=$ress the Attribute 3isibility and Options button to display the receiver attribute color plot now!
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DO IT YOURSELF #16 "t is now possible to define different symbols for different instrument types! 7pen Ifullfold!masJ and select Edit 2eceivers from the 2eceiver Display?Options button submenu! Choose group selection mode; select *nstrument from the list box; and then clic6 out a box around some of the land receivers! "n the Iefine "nstrumentJ dialog; choose new instrument from the list and add a multi component phone 9, to the new instrument! Dou can display this new instrument with a different symbol by chec6ing the Override De,ault Symbol option! Chec6 this option and choose a different symbol for the new instrument! $ress O; to close the dialog! Select Edit 2eceivers again to exit the editing mode! Dou should now see the different symbols in the esign Gindow! @otice also that the legend has the instrument name listed for the new symbol! Try creating some different instruments for sources and water receivers!
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E=E2+*SE >1 // Overvie- o, 2ecent Features7 Part * This exercise demonstrates several features from recent MESA releases and how they might be used to solve a variety of design and integration problems!
,!= 7pen MESA! "n addition to displaying raster images; contour files; and vector files; MESA now supports the display of Shapefiles! Select Shape,ile Manager from the dropdown menu of the Shapefile display toggle button!
The Shapefile Manager window will appear! Shapefiles can be loaded as individual files or by selecting entire directories containing multiple Shapefiles! 'or this exercise; press the Add Files button and open IyampaYcanyon!shp!J The filename will appear in the Shapefiles O raw 7rder listbox! Ghen you select a file in the listbox; additional controls for setting Fill Pattern7 Fill +olor7 and Outline +olor appear in the window! 'or this example; leave the default settings intact!
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$ress the O; button to return to the esign Gindow! The Shapefile layer can be shown or hidden by pressing the Shapefile isplay toggle button!
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%!= 7pen the exclusion editing toolbar! $ress the 2ead Exclusion File button! 7pen IyampaYcanyon!xclJ to load a set of previously defined exclusion Bones!
Ghen you are importing exclusions from another pro?ect; you will get prompted with another dialog box which lists all the exclusions Bone in the file! Dou have the option of selecting a subset of exclusions! This can be useful if you want to import boundaries or roads from an ad?oining pro?ect but not all of the cultural features! 'or this example; we want to import all of the exclusion Bones in the external file! y default; all of the Bones in the list should be selected! "f this is not the case; press the Select All button! $ress to O; button to load all of the exclusions into the pro?ect!
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Exit the exclusion editing toolbar!
Dou should now see the exclusion Bones in the esign Gindow! "n this exercise; we are dealing with an interesting area with multiple survey design challenges! There are several streams; a
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large river; numerous historical sites; and a few bird nesting areas which are off limits for ac-uisition e-uipment! 3!= )ay out an orthogonal survey! Select .ayout/@2eceivers/@.ines?!ric0s! 'ill out the parameters as shown below to create receiver lines with spacings ,,/ inline; 88/ crossline; / degrees inline bearing; and 4/ degrees crossline bearing! Also; select the Fill one option and select the oundary layer and the Survey oundary exclusion Bone to fill! 9epeat the process for the source lines; but swap the bearings such that inline L 4/ degrees; crossline L / degrees! Also; since we want to offset the source points; ma6e sure that =/Shi,t and J/ Shi,t are set to 00 feet! 9efer to the following diagram for the parameters!
Dour survey should appear as shown in the following diagram! The diagram includes a Boom of the SG corner of the survey; showing that the sources lines are offset 00 feet inline and crossline from the receiver lines! oom in on your survey to verify that you have the correct layout before proceeding!
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(!= Ghen you lay out source and receiver lines after defining exclusion Bone; the effects of the exclusion Bones are not automatically recalculated! 7pen the exclusion editing toolbar!
$ress the 2ecalculate E,,ects button! Dou will see all of the sources and receivers inside the exclusion Bones turn gray\which indicates the points are now dead! Exit the exclusion editing toolbar! Save your database as Iyampa,+J before proceeding! 0!= "n the next phase of this exercise; we will review some of the tools for analyBing how much of our survey is affected by the obstacles in our design area! To do this; we will use the source and receiver attributes feature! Select Add?2emove Attributes from the attribute drop down menu!
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$ress the Add button and add an integer source attribute named IobstructionsJ!
9epeat the process and create an integer receiver attribute named IobstructionsJ! *!= y default; attribute data are initialiBed with a null# value! As a review of spreadsheet functionality; select .ayout/@2eceiver Spreadsheet! Scroll the spreadsheet horiBontally until you can see the IobstructionsJ column! Enter a value of Bero in the first row! Clic6 the left mouse button on the column title
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Close the receiver spreadsheet! Select .ayout/@Source Spreadsheet and repeat the process with the sources to initialiBe the obstructions# source attribute with Beroes! Close the source spreadsheet when you are finished! +!= Ge are now going to use the exclusion Bones to assign source and receiver attributes for the various types of obstructions! Ge will use the following assignments2 Obstruction (ype @o obstruction 9ivers @esting Areas Archaeological Sites
Attribute 3alue / , % 3
Ge have already initialiBed a ma?ority of the sources and receivers with an a ttribute value of Bero
This will open the Exclusion 9ecord Attribute Settings dialog box! This interface allows you to set an attribute value for all of the receivers that fall inside a particular exclusion or inside any of the exclusions for a selected layer! "n this exercise; we are going to set values for entire exclusion layers! 'ill out the parameters as shown in the following diagram2
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Select Set by Selected .ayers! Select 9ivers# from the .ayer list! Select obstructions# from the Attribute list! Set the attribute 3alue e-ual to ,! $ress the O; button to finish! The dialog box will close! Ge need to repeat this process for nesting and archaeological sites! $ress the Exclusions Attribute Settings button!
This will reopen the Exclusion 9ecord Attribute Settings dialog box! 'ill out the parameters as shown below to set the attribute value e-ual to % for the nesting areas! $ress O; to finish!
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9epeat the process a third time to set the attribute value for the archaeological sites! 'ill out the parameters as shown below! $ress O; when you are finished!
Exit the receiver editing toolbar! 7pen the source editing toolbar and repeat the exact same process for the sources! Assign the same three attribute values for source obstructions that you assigned for receiver obstructions! Exit the source editing toolbar when you are finished!
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8!= Fiew the attribute data to verify that you have made the assignments properly! Select Attribute Display from the attribute drop down menu!
Select obstructions# for the source and receiver attribute to display!
$ress the Attribute Display toggle button in the esign Gindow to view the attribute data! oom and scroll around your survey to verify that the attributes have been assigned properly! The color scale should range from /:3 with most of the sources and receivers showing an attribute value of Bero! Sources and receivers should have a value of one in the rivers; a value of two in the
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4!= There are several methods for analyBing attribute data! Ge have already been loo6ing at attributes in map view! Another method is to use the attribute histograms! Select 'tilities/ @istogram
$ress the O; button to plot the histogram!
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'rom the plot; we can see that +8,( of our sources have a value of /!/
$ress the istogram Settings button and change the display to a histogram of receiver attribute data!
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The percentages are similar for the receiver data!
Close the histogram window! ,/!= Another method for loo6ing at the distribution of attribute data is to use pie charts! Select 'tilities/@Pie +hart
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y default; the pie chart window will automatically divide the data into ranges! 'or this exercise; we will ta6e control over the plot settings! Select the Detailed +hart radio button! $ress the Add button to define the first pie wedge in our chart! 'ill out the Chart etails parameters as follows! Since we are plotting integer data; set the value range from /!//:/!44!
$ress the Add button three more times to add three more pie wedge definitions! 'ill in the parameters as shown below!
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$ress O; in the $ie Chart Settings dialog box to create your chart!
To change the chart to receiver data; press the Pie +hart Settings button!
This will re:open the $ie Chart Settings dialog box! Select the 2eceiver Attributes radio button and select obstructions# from the Attribute drop down list! The detailed chart settings are retained from the previous chart; so you can simply press O; to plot the receiver data! "ndividual pie charts can be saved as snapshots# and re:opened for comparison! Ghen you select Save Snapshot from the drop down menu; you will be prompted to save your chart with a uni-ue name!
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Call you snapshot I9eceiver 7bstructionsJ and press O;!
To recall a copy of your saved chart; select Open Snapshot from the drop down window! Select 9eceiver 7bstructions# from the list and your saved chart will open in a new window!
Snapshots can not be edited or modified; but are useful for comparison purposes! Close all of your pie chart windows before continuing with the exercise! ,,!= 7ne of the more time consuming aspects of designing a survey is adapting the sources and receivers for culture and topography! "n this phase of the exercise; we are going use the automatic repelling feature to move receivers outside of exclusion Bones! oom in on your map on the western edge of the design so that you can see the large bend in the river and one of the
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The results of this feature will be easier to see if you first change the receiver symbols! Select Display/@Options and change the receiver symbols from plus signs to another symbol; such as a solid circle! Also; change the IdeadJ color for receivers from light gray to orange and press Apply! 7pen the receiver editing toolbar! The first thing to do is to set up a grid for moving receiver points! $ress the Design Grid Options button!
Ge need to set up an editing grid! $ress the Auto Fit button! @ext; change the *nline Spacing and +rossline Spacing to ,,/ feet if necessary! Ferify that the *nline !earing is set to / degrees! $ress the O; button when the settings are correct!
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)et#s say that you have some guidelines for moving receiver locations! $erhaps you will allow receiver moves perpendicular to the receiver line in increments of ,,/ feet; but no move can exceed half of the receiver line spacing <,5% of 88/ feet L ((/ feet=! $ress the Exclusion 2epulsion Mode button!
efore clic6ing anywhere in the esign G indow; we need to set up our rules for moving receiver points! $ress the 2epelling Options button!
This will open the 9epelling 7ptions dialog box! The first tas6 is to set the rules for receiver movement in the Movement .imits group box! Since we are restricting our receiver movement to the crossline directions; select the +rossline radio button! Since we are restricting our crossline movement of receiver points to ((/ feet; set the Max Grid Points to ( <( grid lines ] ,,/ feet L ((/ feet=! Ma6e sure that the Max Grid Points for the inline direction is set to Bero! 9efer to the following diagram for the parameters!
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There are two modes of exclusion repelling! Dou can manually clic6 on exclusion Bones; or you can automatically repel from all exclusions in a given layer
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Clic6 the left mouse button *6S*DE the river! All of the receivers inside of this exclusion Bone will now be moved in the crossline direction according to the rules we have set up! Dour screen should now loo6 as follows2
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"f you loo6 at the orange receivers; you will see that they have been moved to grid nodes outside of the river! "f you clic6 *6S*DE the river a second time; the process will be reversed and the orange receivers will be moved bac6 to their original positions! This is one of the few undo# functions in MESA! "f the movement rules do not produce the desired result; this gives you a chance to refine the rules without ruining your survey! Please note (he undo ,unction only -or0s on the last exclusion #one you choose% Once you select another exclusion #one7 you can not undo previous -or0% )eave the river exclusion with the receivers repelled outside of the river! @ext; clic6 the left mouse button on the
7nly the three receivers
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After you press O;; all of the receivers that can be moved according to the rules will be moved! $an around the display to loo6 at the results of the repelling feature! Exit receiver editing mode! To complete this phase of the exercise; return to Display/@Options and change the receiver dead color bac6 to light gray! ,%!= 9epelling the receiver locations does not automatically turn the receivers live! 7pen the exclusion editing toolbar and press the 2ecalculate E,,ects button! 9efer to step 1( of this exercise if you don#t remember how to perform this function! ,3!= Dour survey design now has the receivers moved to accommodate the obstructions in the area! Any receivers that had to be moved more than ((/ feet in the crossline direction have are still dead! All of the source points are still in their pre:plot locations! )et#s loo6 at our CM$ coverage for this design! $ress the Shoot button and define a ,* line by ,%8 receiver template! .se Automatic (emplate +entering with template roll on5off and shoot the survey! efine your bin grid with 00 x 00 feet bins and a line bearing of 4/ degrees! $erform a full 'old; 7ffset; and ABimuth fold calculation! isplay the fold map! "t should appear as follows2
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As expect; we have some lower:fold holes to fill in due to our dead source locations! ,(!= Ge will perform the same exclusion repelling wor6flow on the sources
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Ge will use similar guidelines for moving source locations! Ge will allow source moves perpendicular to the source line in increments of ,,/ feet; but no move can exceed half of the source line spacing <,5% of 88/ feet L ((/ feet=! $ress the Exclusion 2epulsion Mode button!
efore clic6ing anywhere in the esign G indow; we need to set up our rules for moving source points! $ress the 2epelling Options button!
Ge can use the same rules for source movement that we used for receivers! Select the +rossline radio button! Set the Max Grid Points to ( <( grid lines ] ,,/ feet L ((/ feet=! Ma6e sure that the Max Grid Points for the inline direction is set to Bero! Select the 2epel From Select .ayers radio button! Ma6e sure that three exclusions layers <9ivers; @esting; and Archaeological Sites= are selected in the listbox! As a final step; chec6 the Do 6ot Allo- Move *nto Selected Exclusions chec6box! This will 6eep sources from moving out of one exclusion Bone into another exclusion Bone! efore pressing the O; button; verify that your parameters are set as follows2
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Exit the source editing toolbar! ,0!= 9epelling the source locations does not automatically turn the sources live! 7pen the exclusion editing toolbar and press the 2ecalculate E,,ects button! 9efer to step 1( of this exercise if you don#t remember how to perform this function! After performing this calculation; a chec6 of the land survey statistics shows that there are 8,8( total source points in your survey! 8,%/ sources are live and +8,( sources are fired! This means there are 3/* source points that have been moved outside of the exclusion Bones and could now be fired <*( source points did not get moved due to our exclusion repelling rules=! ,*!= There are various methods for shooting new source points that have been added to a design! "n this case; we have 3/* sources that don#t have a template assignment! Ge need a method for easily shooting these additions without disturbing the template assignments for the other source points! The best choice is to set up a source filter! Select Filter Options from the pull down menu!
Set up a source filter such that 'ired is 'A)SE A@ "s )ive is T9.E
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$ress O; to exit filter definition! $ress the Filter button in the esign Gindow to apply the source filter! Dour map should appear as shown in the following diagram2
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,+!= Gith the filter applied; we can now shoot the unfired sources without affecting the template assignments for the rest of the source points! $ress the Shoot button! .se Automatic (emplate +entering
,4!= There are several ways to loo6 at offset distribution data in MESA! Select !in Analysis/ @Fold +rossplot from the main menu! The 'old Crossplot window will appear! The default display shows the color:coded fold in discreet offset ranges for the first inline bin line!
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.se the arrow 6eys to step forward and bac6ward through the bin lines! $ress the !in .ine button to draw a line in the esign Gindow showing the current bin line! Dou can also directly type in the bin line number into the edit box! Type ,8/# into the edit box and press KC9X!
Dou can see in the display that the large nesting exclusion Bone in the eastern half of the survey is affecting the near offsets! A more dramatic way to see the missing offsets is to switch to horiBontal slice mode! $ress the ori#ontal Slice button and step down to the ,0// feet offset slice! The holes in offset coverage are very apparent!
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Switch bac6 to *nline !in mode! "n addition to loo6ing at coverage in the offset domain; you can also use this window to visualiBe how mutes will affect your coverage! $ress the (ime Mode button and return to inline bin row ,8/! Dour screen should appear as follows2
The display is now showing the fold as a function of time! Since we don#t have any mute functions defined; the fold is constant for all time steps! Ge do see the same reduction in fold between bins 3//:((/ due to the missing near offsets! $ress the Mute Functions button! The Mute 'unctions window will appear!
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$ress the First !rea0 Mute button
$ress the O; button! The mute function should now be displayed in the window!
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Close the mute function window! The mute will not be immediately applied to the data in the fold crossplot! .se the arrow 6eys to step forward one bin line to see the mute applied to the fold plot for inline bin line ,8, as shown below!
As expected; the missing offsets also manifest themselves as significant reductions in coverage when combined with a first brea6 mute! Spend a few moments analyBing the time domain fold crossplot in the crossline and horiBontal slice domains! Close the fold crossplot before moving to the next step in the exercise!
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%/!= "t is -uite common to test various template siBes and shapes during the design process! 'or simple surveys; it is an easy matter to unshoot the survey and reshoot it with a different template! ut what about situations where the shooting was difficult or the template information had to be imported and you don#t want to 6eep repeating the shooting process^ ow do you 6eep multiple sets of template assignments in a single design pro?ect^ Select Shoot +on,iguration Manager from the drop down menu!
The Shoot Configuration Manager window will appear! The ,*x,%8 templates used during this pro?ect as stored as the shooting configuration named IefaultJ in the listbox!
)et#s say that we decide the long offsets in our original shooting template might not be necessary and we want to reshoot the survey with circular templates instead! $ress the Add 6e- Shoot +on,ig button! Ghen prompted to enter a name for the new shooting configuration; enter ICircularJ! The new entry will appear in the list box! Select Circular# from the list and press the O; button!
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This shooting configuration will now be applied to the survey! Since we haven#t shot the survey yet for this configuration; all of the sources in the esign Gindow should have turned bac6 to their IunfiredJ color
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$ress the Shoot button! efine circular templates with a /:+/// feet offset range and re:shoot the survey! After shooting is finished; select 'tilities/@Edit (emplates to verify the template assignments!
Exit edit templates mode! $erform another fold calculation to see the results of this new shooting template! "n the 'old Calculation dialog box; create a 6amed Fold +alculation and name the result yampa,+ O circular#! See the following diagram for the parameters!
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)oo6 at the fold map in the esign Gindow!
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As expected; the coverage is similar to the rectangular templates; but the overall fold is lower since we reduced the longer offsets! Select !in Analysis/@Fold +ompare! ifference the efault Mesa 'old Calculation# with yampa,+ O circular# and store the result in 'old difference#! 9edisplay the fold map to show the difference map!
To change bac6 to the rectangular templates; re:open the Shoot +on,iguration Manager and select the efaultJ templates again! 9eturn to 'tilities/@Edit (emplates and verify that the original rectangular templates have been restored! Exit Edit Templates to continue the exercise!
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@ote2 'old calculations are not automatically tied to shooting configurations! Dou should use named fold calculations when using multiple shooting configurations\or you should recalculate the fold every time you switch shooting configurations! %,!= MESA can be used for functions beyond traditional survey design! "t can also be used for pre:plot vs! post plot comparison! "t can be used as a production trac6ing tool! "t can also be used as a repository for auxiliary information related to the pro?ect! )et#s say you are using MESA to 6eep trac6 of information gathered while scouting the pro?ect area! As we have seen; there are some archaeological sites in this area! oom in on a particular polygonal archaeological exclusion Bone
Suppose this site is so sensitive that you need to provide special instructions that not only is e-uipment not allowed; foot and vehicle traffic from the crew is also prohibited! Dou can use the 6ote feature to 6eep trac6 of these restrictions! Select +reate 6ote from the drop down menu!
@otes are tied to map locations! Clic6 the left mouse button inside of the yellow polygon exclusion Bone representing the archaeological site! The @ote dialog box will appear! @otes need to have a uni-ue (opic and uni-ue text for the note! Dou also need to provide a +ategory for the note
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Select K@ew CategoryX from the +ategory drop down list! Dou will be prompted for a category name! Enter AnasaBi#! $ress O;!
'ill in a (opic and additional text for the note! The following diagram shows an example of the type of information you might store! 'or this exercise; it is not necessary to enter all of the note text
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Along with the text for the note; you can also attach external files to the notes! $ress the Attachments button! The Manage Attachments dialog box will appear! $ress the Add button! "n the Add Attachment dialog box that appears; press the Add File button! 7pen the file yampaYarchYsite!?pg#! 'or the Attachment Description; enter photo of sunrise house#!
$ress O; to close the Add Attachment dialog box! The attached file will now be listed in the Manage Attachments list box! $ress Done to close the Manage Attachments dialog box! $ress O; to close the @ote! A default symbol
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@otes are ob?ects that can be displayed and recalled! $ress the Pro8ect 6otes button in the esign Gindow to toggle the note display on and off! Select 6ote Settings from the drop down menu to label the notes in the esign Gindow! Chec6 Sho- 6ote (opics and press O;!
Dou should now the label Sunrise ouse welling# attached to the note! To recall a note; change the Find 2ecord settings to 6otes%
old down the KshiftX 6ey and clic6 the left mouse button on the symbol representing your note! The note will appear! $ress the Attachments button in the Manage Attachments dialog box!
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ouble:clic6 on the attachment
Dou may load any type of attachments into the note database! "f you store spreadsheets or text documents; those files will also auto:load if you have the file associations defined! Close all of the note:related dialog boxes before continuing with the exercise! %%!= The final steps in this exercise deal with some recently:added output formats that can assist in transferring your pro?ect to other mapping systems! Select Output/Shape,ile Output! Dou will be presented with a simple interface for exporting sources; receivers; and exclusion Bones to a Shapefile!
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Select all three chec6boxes! $ress O;% Dou will be prompted for three file names! Accept the default file names
Ge use a default blac6 plus sign for our default symbol in the Shapefile output! "f you wish to change the display; return to the Shape,ile Manager and change the symbol; siBe; and color for the sources and receivers!
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%3!= MESA designs can also be output to >M format for use in the application &oogle Earth! Select Output/@;M Output! Dou will be prompted with the following interface!
Dou have the option of exporting source locations; receiver locations; exclusion Bones; the default fold map; and bac6ground raster images to the >M file! 'or this exercise; select Sources7 2eceivers7 and Exclusions! ata in the >M file are stored in latitudes and longitudes; so you need to define a map pro?ection! $ress the +hange +oordinate System button! The Map $ro?ection dialog box will appear!
Set the Pro8ection to .S State $lane#! Set the one to C7 @ O /0/,#! Set the Datum?Ellipsoid to @A%+#! $ress O; to close this dialog box! The new coordinate system will appear in the
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>M 7utput dialog box! $ress O; to proceed! Ghen prompted; name the output file Jyampa,+!6mBJ! "f you do not have &oogle Earth installed on your computer; the exercise is finished at this point! "f you have &oogle Earth on your computer; open a G indows Explorer window and find yampa,+!6mB on your computer! ouble:clic6 on this file and the data will automatically load into &oogle Earth
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Glossary o, (erms !in
The fundamental sub:surface sampling interval; typically ` the inline receiver spacing in width and ` the inline source spacing in height! Source:receiver midpoints that fall in this area are considered to be from the same common midpoint and contribute to the fold count!
!ox
"n a regular orthogonal 3 survey this is defined by the area bounded by two ad?acent source lines and two ad?acent receiver lines and represents the smallest area of a survey which defines all statistics!
+MP
Common midpoint; or the point halfway between the source and receiver!
+MP bin
A small s-uare or rectangular area often of width e-ual to half receiver spacing <9"= and length of half source spacing
+2P
Common reflection point; or the point on a subsurface model horiBon that reflects from a source to a receiver!
+ontour File
&M&#s contour file format
Exclusion one
Fold
A restrictive Bone within a survey! This can include areas where no sources; receivers; and5or midpoint information can be recorded! Examples include wells; pipelines; buildings; and rivers! The number of midpoints that fall within a CM$ bin! 'or simple surveys with s-uare or rectangular bins
Geo/ 2e,erencing
A procedure performed by &M& "mage which defines the coordinates for each pixel in a graphic image; based on the pixel scale of the image and the coordinate of the upper left pixel of the image!
GMG *mage
A utility program which is included with &reen Mountain &eophysics# software which geo:references and reformats graphics files< !tif and !dxf; for example= and creates contoured files of attributes
alo
.ayer File
&M&#s image file format
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