Point Code Prefixes and the Code Table
Point Code Prefixes and the Code Table The codes that are assigned to points are used by n4ce to generate graphical information. These codes can be defined whilst surveying in the field or when creating designs in the office. The description of the feature to which a point belongs can be further refined by the use of comma codes, dimensions and remarks.
Point Codes Any point code should be in upper case characters and comprises three elements. These are a code prefix, a string number and comma codes. Code Prefix
This defines what the points of a given feature string represent. Code prefixes are normally alphabetic characters although numeric characters can be used. An example of a code prefix would be BB which may represent a bottom of a batter. You can use as many characters as you wish but it is best to try and use as few as possible as this reduces time to record the code in field.
String Number This allows you to differentiate between the feature strings that use the same code prefix. These would normally be numerical. For example, two different bottoms of batter could be code as BB01 and BB02. The use of string numbers is not compulsory. Comma Codes These are additional items that allow you to change the behaviour of a feature at any given point. They are single characters and are appended to the end of the feature code prefix and string number combination. They are separated from the code and string number by a user definable character, normally a comma. You can use more than one comma code at each point but only one separator character is necessary. Point dimensions are items of information that can be attached to points, either in the field or in the office. They take the form of name=value where the name is the label assigned to the dimension and value is its value. Most, but not all, dimensions are likely to be numerical and you can attach as many dimensions to a point as you wish.
The Code Prefix Dialog The code prefixes that you wish to use are defined using the Survey Code Prefixes Dialog. This can be accessed using the Display Codes option from the Settings menu of the n4ce main window. It can also be accessed from a similar option in some of the graphic views. When selected, the dialog box shown below will be displayed.
The Prefixes list shows the code prefixes that have already been defined. There is always a code prefix called Default. This prefix is used when n4ce cannot find a prefix that matches the code of a point.
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n4ce Manual You can create new code prefixes using the Add button. You will be asked to enter a new code prefix and a copy of the prefix highlighted at the time the button was selected will be made. A new prefix will be created with those copied attributes. The Remove button can be used to remove existing code prefixes. After a check, it will be removed from the list. If the default code prefix is highlighted, this button will be disabled. The main part of the dialog is a property sheet consisting of nine pages. The first eight of these pages defines an item that can be displayed and will be described in its own section later in this chapter. For each code prefix, you can display as many of these items as are required. The ninth page allows you to enter defaults for dimensions. The Transfer field allows you to define a prefix which is used when importing data from and exporting data to MX GENIO files. When exporting data to this format, you will be given the option to translate the code prefixes. When importing data from an MX GENIO file, if an imported code can be matched to a transfer prefix, the code prefix will be used for the code. In both case, if no transfer prefix is defined or one cannot be found, no code translation takes place. The Description field defines a descriptive text string of the current code prefix. The Code Import Convention field defines which of the four code import conventions are to be used.
Loading and Saving Code Defaults There is a default set of code prefixes that is stored in a known file that is loaded every time a new project is created in n4ce. The file normally has the path C:\ProgramData\Applications in CADD\n4ce\Settings\codes.ini. You can however save different sets of code prefixes to different locations. This is useful where you have a number of clients who require the use of different code prefixes. There are other defaults which can be saved and loaded in the same way. It is suggested that you create a file directory under the n4ce Settings directory for each client and save all their defaults in that location. To save the code prefixes in the current project, select the Save option from the File menu at the top of the dialog box. When the file dialog is displayed, the default file will be that storing n4ce’s own set of default prefixes. To load code prefixes from a file other than the standard file, select the Load option from the File menu. You should do this when creating a project for a specific client who requires different prefixes.
Purging Unused Code Prefixes On the File menu at the top of the dialog box, there is a further option called Purge. This allows you to remove any code prefixes that are not used by any survey, co-ordinate block or DTM in the project. After selecting the option, n4ce will analyse all of its data and if it finds code prefixes that have not been used, they will be displayed in a dialog box as shown to the right. This lists the code prefixes together with the description that each has been assigned. Each code prefix will have a green tick or a red cross next to it. Those assigned a green tick will be removed from the project when the OK button is selected, whilst those with a red cross will not. You can change whether a prefix is to be removed or not by either double-clicking over it in the list or by the use of the Keep, Purge or Invert buttons.
Creating the Feature Strings When displaying survey data, the codes of the points or observations are analysed and where a sequence of codes is the same, those points are used to create a feature string. The default way of working is that when the code changes, a new string is started. However, if the Auto Stringing check button is ticked, n4ce uses a slightly different algorithm. In this case, the strings that have already been created will be searched, on a last in first out
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Point Code Prefixes and the Code Table basis, to see if there is a feature string with a code matching that of the current point. If a match is found, the point is added to that feature otherwise a new string is created. This option only works when displaying survey data and not model data. When creating a model, the strings that are created for display are copied into the model. It also works across survey instrument set ups so that the points that make up a feature string can be found in more than one set of observations.
Point Comma Codes The Comma Codes button from the Survey Code Prefixes Dialog allows you to define which single character to expect for some of the comma codes that are available. Currently, some of the comma codes that can be used are fixed to a certain character. When selected, the dialog shown to the right will be displayed. Comma codes are referred to as such because the comma is what n4ce uses to separate the comma codes from the main part of the code string. However, on some survey instruments and data loggers, it can take a number of key presses to produce a comma character. The Separators field allows you to specify one or more alternative characters that can be used. When survey information is imported, the existence of any one of the specified characters will allow n4ce to recognise comma codes. When n4ce displays comma codes, it always uses a comma character. A number of the comma codes in the above dialog refer to a specific type of feature display and these will be described in the appropriate section of this chapter. Those that are not specific are described below.
Point Heights The No Model comma code, normally X, specifies that you do not wish the point to be included into the DTM triangles. This is necessary where the level of the point would have an adverse effect on the model, such as an observation to the eaves of a building or underground services. If this comma code is set, the height of the point may still be displayed. The 2D comma code, normally Y, specifies that the point does not have a valid height and is to be treated as 2D. If it is a surveyed observation, no height will be calculated when survey reduction takes places. If the point has been created by other means, any height assigned to the point is ignored. Therefore, the point will not be used in the DTM triangles and any height cannot be displayed as annotation. The No Height comma code, normally Z, overrides any display of the point height. If the point code prefix requires the display of a height, it will not be. The point can stilled be used in the DTM triangles. The automatic addition of this comma code is an option when using some of the feature editing tools in the model.
Other Comma Codes The New Code comma code, normally N, specifies the start of a new feature string. This is used where two successive features use the same code and is useful in the field where you do not wish to use feature string numbers. Whilst it normally applies to line features, it can be used on any type of feature. This comma code can also be defined for a point by the addition of a ‘+’ character to the end of the point code. This only works when data is being imported. Once imported, the plus character will be removed and the normal comma code displayed in its place. The Ignore comma code, normally I, only applies to surveyed observations. If used, the observation will be ignored when creating a model from the survey or when performing the calculations for reductions, traverses and resections. When a survey is reduced, the co-ordinates of the ignored points will be displayed in the data grids.
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n4ce Manual Point Dimensions Dimensions are used on points to give further information to n4ce about the object at a survey point. For instance, if the point represents a tree, you can specify the spread of the tree canopy, the size of the tree bole and the height of the tree using dimensions. The tree species could also be defined by a dimension. Dimensions are expected in the form of name=value where the name is the label assigned to the dimension and the value is a string representing the dimension. Most dimensions are likely to be numerical although they can be alphanumerical as needed. You can add as many dimensions as you wish to any point. There are certain dimensions that are required in given circumstances. For instance when displaying a tree at a point, a CAD symbol is normally used to show the canopy. This CAD symbol will need to be scaled to represent the actual size so a scale dimension will be expected. The Dimensions button from the code prefixes dialog allows you to define the names that n4ce should expect for these predefined dimensions. When selected, the dialog box shown above will be displayed. One of the pages on the main property sheet of the code prefix dialog is called Fields. This can be used to set default values for dimensions so that you do not always have to assign dimensions in the field. In some situations, if a dimension has not been assigned to a point and no default value is found, a value of 1.0 will be assumed. When saving a code file for upload to a survey instrument, you should pay particular attention to this property page. Any dimension defaults that are specified here will also be exported to the appropriate file and uploaded to the instrument. When using the code whilst surveying, you will be asked to enter these dimensions. A number of the dimensions in the dialog refer to a specific type of feature display and will be described in the appropriate section of this chapter. Those that are not specific are described below.
Altering the Reduction of Survey Observations When surveying, it is occasionally not possible to survey the exact point that is required. For instance, when surveying posts and poles, you cannot survey the centre of the pole unless you climb the pole and place your target on top. Four dimensions can be used to adjust the reduction process by, in effect, making a slight alteration to the observed readings. These adjustments do not change the observed values but make slight changes to the co-ordinates that are displayed after the reduction process. The Lateral dimension, normally L, can be used to enter a distance by which the observed reading can be adjusted to the left or the right of the line of sight. This is used in conjunction with the observed distance to make a slight adjustment to the horizontal angle before reduction. If the dimension is negative, the adjustment will be to the left of the line of sight. The Horizontal dimension, normally H, can be used to enter a distance by which the observed reading can be adjusted along the line of sight. This is used to make an adjustment of the observed distance before reduction. If the dimension value is positive, the observed distance will be increased. The Vertical dimension, normally V, can be used to enter a vertical offset by which the reduced point can be raised or lowered. If the dimension is positive, the reduced height will be raised by the dimension value. The circle shape dimensions, Radius, Diameter and Circumference, can also be used to adjust the observed distance. This can be used where you are surveying to the front of a tree trunk or other circular object. The dimension needs to be entered to size the object but this value can also be used to adjust the observed distance. The radius can be calculated from the dimension value but will only be applied if specified in the code prefix used by the point. Refer to the section dealing with the display of shapes later in this chapter.
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Point Code Prefixes and the Code Table The Display of Points The first page of the code prefix property sheet is called Point and an example of this is shown below. The fields in the page allow you to define how the position for each point on a feature using the current code prefix will be displayed. The Enabled check button is disabled for this item. For query purposes, a point is always expected to be displayed. If you do not want a point, there is a point style called None which performs this task. The Layer, Style and Pen fields define the graphical attributes that n4ce will use. The Size field defines the size of the point in millimetres at the view or plot scale. In the example above, 2mm displayed at a scale of 1:500 will display a point that, in real world size, is 1m across. The Model Points check button allows you to specify whether any point using this code prefix is to be used in any DTM triangles. There are situations where the object being displayed is either above or below the ground surface and would have a detrimental effect on the model. Examples of this are overhead wires, underground services and the eaves of buildings.
Comma Codes for the Point Style The No Point comma code, fixed to 0, is used when you wish to turn off the display of any point marker. The automatic addition of this comma code is an option when using some of the feature editing tools in the model. The Dot Point comma code, fixed to 1, is used when you wish to change the display at any point to be a dot point style. The dot point style is useful when transferring models to AutoCAD DXF files where all points may be required but hidden when no height is displayed. This comma code can be added automatically when deleting point height text.
The Display of Lines The second page of the code prefix property sheet is called Line and an example of this is shown below. The fields in the page allow you to define how any lines joining the points of a feature using the current code prefix are to be displayed. The Enabled check button allows you to specify whether a line will be displayed or not. If it is ticked, a line will be displayed using the parameters in the dialog. If not, the items in the property page will be disabled. The Layer, Style and Pen fields define the graphical attributes that n4ce will use. There is also a preview window which shows an example of the line. The Attributes group of the property page consists of a series of check buttons which further refine the line parameters. Most of these are used in specific circumstances and will be described later in this section. There are two that are more general in nature. There are dimensions that allow n4ce to display parallel and offset lines using the surveyed line feature. In normal circumstances when creating a model, these lines are still displayed but there are no points at the line apexes and so they cannot be queried or modelled. If the Commit P,O&W check button is checked, n4ce will create new features to represent the parallel lines. Any offset lines will be moved from their surveyed location to the offset position as displayed on the screen. The Force in DTM check button allows you to ensure that the line segments of the line feature form part of the DTM triangles. This is necessary where there are sharp changes of slope such as at the tops of embankments.
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n4ce Manual Polygonal Line Features Some features, such as building footprints, are often closed polygons where the last point links back to the first. There are two ways that you can force a line feature to be a polygon. The Polygon comma code, normally P, can be assigned to either the first or the last point of a feature. This can be used for “one off” features that need to be closed, such as the feature strings around the bottom of a series of spoil heaps. The attribute check button Auto Close allows you to specify that all features using a particular code prefix are polygons. This can be used where the feature represents a building footprint or a pedestrian refuge in the middle of a carriageway. You should note that when displaying the closing segment of a polygonal feature, any curve fitting is carried through from the end of the feature back to the beginning.
Curving Line Features There is often the requirement to display part or all of a line feature as curved segments. Kerbs in towns and cities are seldom straight. The Curving comma code, normally C, specifies that the line feature generated using a given point will be curved at that point. A curve can only be generated if one of the curve comma codes has been applied to both points of a line feature segment. If the line segment prior to the point is straight, a discontinuity in the curve will exist. The same applies where the following segment is straight. If both prior and following segments are curved, there is a common tangent direction at the point. The Curve Discontinuity comma code, normally D, specifies that if both the prior and following line feature segments are curved, there is no continuity of the curve direction through the point.
Straight Feature
Curved Feature
Curved Feature with Discontinuity
The first of the examples above show the starting point of a feature made up of straight line segments. The second shows how curve fitting is applied to all the segments of the feature. The third shows how a curve discontinuity can be introduced to one of the points. The Tangent comma code, normally T, specifies that the line feature segment prior to or following the point is a tangent. If the prior segment is straight, the direction of this segment is used to constrain the start direction of the following segment. If the prior segment is curved, the direction of the following segment is used to constrain the end direction of the prior segment. Some examples are shown below.
Single Tangent
Double Tangent
Quadruple Tangent
The first of the examples above shows how a series of curved segments are followed by a straight segment using a tangent point. The second shows how a single curved segment can be created between two straight line
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Point Code Prefixes and the Code Table segments by using two tangent points. The third shows how a four point polygon with four tangents can be used to simulate a pedestrian refuge in a road.
Parallel Line Features It is possible to use dimensions that create lines that are parallel to surveyed lines. For instance, you could survey one face of a wall and create a parallel line that represents the other. The Parallel dimension, normally P, is used to do this and can be placed on either the first or last point in the feature string. If the dimension is assigned to any other point in the feature, it is ignored. Note that if the attribute check button P,O&W on First Only is ticked, the dimension can only be assigned to the first point of the feature. In its simplest form, there will be two parallel lines drawn using the same line style and pen. The distance between them will be the dimension value. The first of these lines will be drawn on the surveyed line and the other to the left or right. If the dimension value is negative, the second line will be to the left of the first. You can further enhance the parallel line by defining the dimension as series of up to three comma separated strings, for example P=offset,prefix,dz. The first string is the value of the parallel offset, the second string is the code prefix that is to be used to display the parallel line and the third string is the value of any height offset from the first to the second string. This can be used to create a combination of channel and kerb lines. You should note that this will only work for features where the height offset is assumed to be constant. If the attribute check button Close Ends on P&W is ticked, the ends of the two lines will be joined by additional segments to create a closed polygon. If the parallel line is using a different code prefix to the surveyed line, the closing segments will use the line style and pen of the parallel line.
Parallel
Parallel with Code
Parallel with Code (Closed Ends)
The first of the examples above shows a simple parallel where only an offset value is provided in the parallel dimension. The second shows a parallel with curved segments where an offset and a code prefix are provided in the parallel dimension. Using these two examples, the offsets from the first point to its calculated parallel show how the parallel calculations are affected by curve fitting. The third is the same as the second except the code prefix settings have been modified such that option to close the ends of the surveyed and parallel lines is enabled. The actual calculations of the parallel line can depend on which comma codes and dimensions have been assigned to a point. The normal parallel method for straight line segments is to create parallel segments for the two segments before and after each point. Where these segments would intersect, a point is created. If there is curve fitting through a point, a tangent to the curve is calculated and a perpendicular offset calculated. If any point on the base string has a Bearing dimension, BRG, a perpendicular offset is calculated using this dimensions.
Offsetting Line Features The Offset dimension, normally O, can be used to offset the line feature to the left or right of the surveyed line. This dimension can be assigned to either the first or the last points on the feature. Note that if the attribute check button P,O&W on First Only is ticked, the dimension can only be assigned to the first point of the feature. If a line feature is offset, the surveyed points will be displayed where they were recorded. It is the display of the line feature that will be offset. If the dimension is negative, the line will be offset to the left. You can use this in conjunction with the parallel line dimension to create asymmetrically spaced lines.
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n4ce Manual
Offset Feature
Negative Offset Feature
Offset Feature with Parallel
In the examples above, the first point on the feature is to the left. The first example shows a feature with a positive offset value. The second shows a feature with a negative offset value. The third shows a feature with a negative offset value and a positive parallel value, with code prefix.
Giving Widths to Lines The Width dimension in lines, normally W, can be used to give a survey feature a width and there are two ways the width can be used. If a feature is width scalable, such as a hedge, the line that is displayed will be scaled up such that the width of the line pattern is the same as the value in the dimension. The attribute check button Width Scalable is used to signify whether a line feature of this type. The attribute check button Offset Half Width will also be enabled and this allows you to survey the face of the feature and offset the displayed line by half the width. For this type of line width, the width dimension can be changed at any point and the new value of the dimension will then be used until it is replaced. You should note that the width of each line segment does not taper between two points. If a feature is not width scalable, you can still apply a width dimension. In this case, two lines will be displayed that are the value of the width dimension apart. The centre line of these two lines is the surveyed feature. In this case, the dimension cannot be changed along the feature and must appear on either the first or last point. Note that if the attribute check button P,O&W on First Only is ticked, the dimension can only be assigned to the first point of the feature.
Width Scalable Feature
Offset Half Width Scalable Features
Feature with Width Applied
The first of the examples above is that of a width scalable feature. The second is the same but with the feature being offset by half of the width. The third is that of a simple line feature width a width applied thus using the surveyed line as the centre line of two parallel lines. Note that the option to close the ends of the feature has been applied using the Close Ends on P&W check box.
Gapping Line Features The Gap comma code, normally G, allows you to suspend the drawing of a line feature for a given segment and should be assigned to the point that immediately precedes the required gap. This may happen where there is a gap in a hedge, a fence or a wall. The example to the right shows a gapped hedge and you should note that the calculations for curve fitting are carried out through the gap as though the segment was there. The attribute check button Alternate Segments allows you to produce a line feature that only displays alternate segments. Examples of this would be a road marking that does not have standard lengths such as the lines of road hatching used for carriageway separation.
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Point Code Prefixes and the Code Table ISO Tree Canopies It is sometimes necessary to survey tree canopies more accurately by recording the spread of the tree in more than one direction. The International Standards Organisation defines that four spreads should be recorded and these should be at the four main compass points from the centre of the tree bole. If attribute check button ISO Tree Canopy is checked, it is assumed that this is what has been surveyed. Each point where a tree canopy is to be produced is assumed to have a Tree Canopy dimension, TC. The dimension string is a comma separated string of the four spreads starting at north and proceeding clockwise around the point, thus taking the form TC=N,E,S,W. The line that is produced at each point is a four point curve fitted polygon. For this option, there is no line connecting the points along the feature.
The Display of the Line The Style dimension, normally LS, can be used to change the line style that a feature uses. It should be assigned to the first point of the line feature and is the name of the line style. This can be used where you are surveying road markings and wish to use one code but select the type of road markings from a list on your survey instrument or logger. The Colour dimension, normally LC, can be used to change the colour that a line feature uses. It should be assigned to the first point of the line feature and is an integer value which maps to the list of colours in the n4ce defaults.
Changing Codes When surveying linear features, it is often required that the same point is used for more than one feature. This can happen where a fence changes into a wall or where a gate is in the middle of a fence. The New Code dimension, normally N, can be used to change the feature code at the current point. The point will be used twice, to end the current feature and to start a new one with the code taken from the dimension value. The point will only be displayed once along with its annotation. The Seg Code dimension, normally M, can be used to change the feature code for the line segment that follows the current point. Just the one segment will use the new code and subsequent segments will revert to using the normal point code. This dimension only works where the segment code is either another line or a two point symbol.
New Code Dimension
Segment Code Dimension
Segment Code Dimension
The first of the examples above shows the use of a new code dimension where a hedge finishes and a fence starts at the same point. The second shows the use of the segment code dimension where a single segment of the hedge is displayed as a fence. It also illustrates how the curve fitting is carried through the feature regardless of the change in code. The third shows the use of the segment code dimension where a single segment of the hedge is displayed as a gate. It is possible to include either of these dimensions into the point code by identifying separator characters for such items. These are defined in the Dimension Strings Dialog. The New Code Separator field defines a character that is used indicate the presence of a new code dimension. In the first example above, with the new code separator being a slash, the point code should be HE01/FE01. The Seg Code Separator field defines a character that is used to indicate the presence of a segment code dimension. In the second and third examples above, with the segment code separator being a colon, the point codes should be HE01:FE or HE01:GT.
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n4ce Manual If you do not wish to use the code separators, ensure that these fields are blank. If you do wish to use them, ensure that the character you have chosen is not alphanumeric and easy access from your total station or data logger keyboard. You should also ensure that you do not use the same characters as those you have specified to indicate a comma code. Also, you cannot use both of these separators on the same code.
Comma Codes and Dimensions for Corners There are a number of comma codes specifically related to building surveys that allow you to alter the shape of line features. An example is to allow the creation of a hidden corner next to a chimney breast or an alcove. At the moment, these comma codes are fixed and cannot be changed. In each of the examples, the solid line is the line that is displayed and the dashed line shows what would be displayed without the comma code. The comma code is placed next to the point in the sequence to which it should be added. The Perpendicular Corner Before comma code, fixed as H, requires a sequence of four survey points with the comma code on the last point. An extra line vertex will be created where a line through the third point which is perpendicular to the line joining the third and fourth points intersects with the line extrapolated from the first and second points. The Perpendicular Corner After comma code, fixed as J, again requires a sequence of four survey points with the comma code on the last point. An extra line vertex will be created where a line passing through the second point which is perpendicular to the line joining the first and second points intersects with the line extrapolated from the third and fourth points. The Corner Merge comma code, fixed as K, requires a sequence of four survey points with the comma code on the last point. An extra line vertex will be created where the line extrapolated from the first and second points intersects with the line extrapolated from the third and fourth. The Corner Before comma code, fixed as L, requires a sequence of three points with the comma code on the last point. An extra line vertex will be created where a line passing through the second point which is perpendicular to the line through the second and third points intersects with a line passing through the first point which is parallel to the line passing through the second and third points. The Corner After comma code, fixed as M, also requires a sequence of three points with the comma code on the last point. An extra line vertex will be created where a line passing through the second point which is perpendicular to the line through the first and second points intersects with a line passing through the third point which is parallel to the line passing through the first and second points. The Segment Offset comma code, fixed as O, requires a sequence of three points with the comma code on the second point. With this comma code, two extra line vertexes will be created such that they represent a line passing through the second point which is parallel to the line created by the first and third points. This can be used to simulate an alcove in a wall.
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Perpendicular Corner Before
Perpendicular Corner After
Corner Merge
Corner Before
Corner After
Segment Offset
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Point Code Prefixes and the Code Table The Line Extension dimension, fixed as X, allows you to extend a line segment into a corner that is not visible from the survey instrument. It should appear on the second of a pair of points where the line between the two points needs to be extended.
The Display of Symbols The third page of the code prefix property sheet is called Symbol and an example of this is shown on the next page. The fields in the page allow you to define how any symbols that are required for a feature using the current code prefix are to be displayed. The Enabled check button allows you to specify whether a symbol will be displayed or not. If it is ticked, a symbol will be displayed using the parameters in the dialog. If not, the items in the property page will be disabled. The Layer and Pen fields define the graphical attributes that n4ce will use. The pen will only have an effect if the symbol was created with all the elements assuming the colour applied to the symbol. This is the same as assigning the colour to BYBLOCK in AutoCAD. The Name field defines the symbol that will be displayed and a preview of the symbol is given in the window beneath it. There are ten different ways in which points can be used to display a feature symbol in plan. The Type field defines which display method is to be used. There is an eleventh option in the list called Section Symbol which is only used when plotting detail on sections and, if selected, nothing will be displayed in plan.
Scaling and Rotating Symbols There are two dimensions that are associated with certain types of symbol. The Scale dimension, normally S, can be used to define the size of symbols and the Angle dimension, normally A, can used to define a rotation of symbols. The angle expected is the polar angle where the positive x-axis is zero and anti-clockwise is positive. If either of these dimensions is expected and not present, n4ce will look at the fields defined for the current code prefix for a default value. If no default is present, a scale of 1.0 and an angle of 0.0 will be assumed. If you wish to scale the symbol, you should create it at unit size. If you wish to angle the symbol, you should create it horizontally so that the correct orientation can be applied. The Retain Scale and Retain Angle check buttons can be used to remember the scale or angle dimensions that are used for displaying the symbol. If these buttons are ticked, the value previously used in a string of symbols will be remembered for each symbol until a new dimension value is assigned. They are only remembered for the current string of symbols so if a new feature string is started, the scale and angle values will be reset.
Symbols Using One Point There are five types of symbol display that only require the use of one point. The symbol could be displayed at every point that makes up the feature. Each symbol will be displayed by matching the origin of the symbol to the feature point. 1 Pt Scaled
This option can create a symbol that can be scaled and rotated about the point. To do this, the scale dimension defines the scale and the angle dimension defines the rotation of the symbol.
1 Pt Aligned
This option creates a symbol that is rotated using the direction of the feature at the point. The symbol can be scaled using the scale dimension. If the angle dimension is present, the dimension value will be added to the direction of the feature at that point.
1 Pt Request
This option is similar to the previous option except that an aligned symbol is only created when requested. If you wish to plot a symbol at a certain point, the Request Symbol comma code, usually S, should be used. The symbol can be scaled using the scale dimension. If the angle dimension is present, the dimension value will be added to the direction of the feature at that point.
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n4ce Manual 1 Pt Ends
This is again similar to the aligned symbol option except that in this case, symbols are only plotted on the first and last points of the feature. In the example to the right, the end points have also had the no marker comma code applied to them. The symbol can be scaled using the scale dimension. If the angle dimension is present, the dimension value will be added to the direction of the feature at the end point. Also, if the feature under consideration is a closed line feature, no symbol is plotted.
1 Pt Fixed
This option is used to display symbols that should always be displayed the same size, no matter what the working scale. This type of symbol is often used for boreholes. The symbol should be created at the size you want it displayed at a scale of 1:1000. Therefore, if a symbol is to be plotted 2mm across, you should draw it 2m across. The scale dimensions has no effect on this type of symbols but if the angle dimension is present, the symbol is orientated accordingly.
1 Pt Scaled
1 Pt Aligned
1 Pt Request
1 Pt Ends
Multiple Point Symbols There are five types of symbol display that require the use of two or more points which give the symbol an origin and a direction. When the necessary symbols are created, you will have to define one or more additional symbol handles in addition to the symbol origin. For a two point symbol, you must provide at least one handle and for a three point symbol, you must provide at least two. The origin of the symbol will always be made coincident with the first point of those to be used. The symbol will be aligned so that the direction between the symbol handle and its first origin will be the same as the direction between the first tow points. When creating the symbols, you should create them so that the line between the symbol origin and the first symbol handle is horizontal. Each of the options calculates a scale factor in the direction of the first two points, Sx, and a scale factor perpendicular to that direction, Sy. There are situations where either of the scales may be taken from the symbol scale dimension and these will be described where appropriate. The symbol angle dimension is not used for multiple point symbols. 2 Pt Aligned
This option is a simple aligning option where the symbol is aligned such that the direction between the symbol origin and the first symbol handle is the same as that between the two points used to construct the symbol. If you define a symbol scale dimension, this scale will be used for both Sx and Sy.
2 Pt Stretched
This option allows you to stretch a symbol between two points by making the second point coincident with the first symbol handle. The Sx value is calculated as the distance between the two points divided by the distance between the symbol origin and the first symbol handle. No scaling takes place perpendicular to the direction of the two points and so Sy is set to 1.0.
2 Pt Scaled
This option allows you to scale a symbol between two points by making the second point coincident with the first symbol handle. Again, the Sx value is calculated as the distance between the two points divided by the distance between the symbol origin and the first symbol handle. The Sy value that is used is the same as the Sx value.
2 Pt Width
This option allows you to stretch a symbol between two points by making the second point coincident with the first symbol handle. Again, the Sx value is calculated as the distance between the two points divided by the distance between the symbol origin and the first symbol handle. The Sy value is taken from the symbol scale dimension. For this option, it is assumed that you have created a symbol that is 1 metre wide.
3 Pt Symbol
This option allows you stretch a symbol between two points by making the second point coincident with the first symbol handle and then use a third point to define a width. The Sx value is calculated as the distance between the first and second points divided by the distance
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Point Code Prefixes and the Code Table between the symbol origin and the first symbol handle. The Sy value is calculated as the perpendicular offset of the third point from a line joining the first and second divided by the perpendicular offset of the second symbol handle from a line joining the symbol origin and the first symbol handle.
2 Pt Aligned
2 Pt Stretched
2 Pt Scaled
2 Pt Width
3 Pt Symbol
Continuous
The Continuous check button is enabled when you have selected the symbol type to be one of the first four options described above. The normal operation of a two point symbol is that points are taken in pairs. Symbols will be created using points 1 and 2, 3 and 4, 5 and 6 and so on. If this check button is ticked, symbols will be created using points 1 and 2, 2 and 3, 3 and 4 and so on. The example shows how the use of the gate symbol can be applied to a feature using continuous two point scaled symbols. If the Continuous check button is ticked, n4ce will also look to see if the Polygon comma code, normally P, has been applied to either the first or last point in the current feature string. If it has been applied, n4ce will create a two point symbol joining the last point on the feature string back to the first. The Hide Second Points check button is also enabled for all multi-point symbols. If this is ticked, only the first point used for each symbol will be displayed regardless of the point display settings. Also, any text or annotation on the second or subsequent points will not be displayed.
The Display of Text The fourth page of the code prefix property sheet is called Text and an example of this is shown below. A text feature is simply a string of text that is usually displayed in conjunction with another type of feature. For instance, it can be used to identify whether a post or pole is a telegraph pole, a lamp post or any other circular shape feature. The fields in the page allow you to define how any text strings that are required for a feature using the current code prefix are displayed. The Enabled check button allows you to specify whether a text string will be displayed or not. If it is ticked, a text string will be displayed using the parameters in the dialog. If not, the items in the property page will be disabled. The Layer, Style and Pen fields define the graphic attributes that are used to display the text. The Readable check button can be used to ensure that all text is readable when reading from the bottom right of the model. If text would be displayed upside down, it will be rotated through 180° about its centre point before being displayed. If the On First Point check button is ticked, the text will only be displayed next to the first point of the feature. The Text field defines the text that will be displayed. If a point using this code prefix has a Text dimension, normally T, the value in this dimension will override the contents of this field. This can be useful where you wish to place a piece of comment text at a given point in the survey or model. For instance, this can be used to indicate the material of an area or the name of a building.
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n4ce Manual Positioning and Aligning Text The Attributes group on the text feature property page defines how you wish your text to be initially positioned on a survey or a model. In a model, you have the option to edit these values at a later date. The X Offs and Y Offs fields define the offsets of the text string from the point. The units used are in millimetres at the view or plot scale. You do have the option to angle text, either using a specified angle or using the direction of line features. If an angle is used, offsets are applied parallel and perpendicular to that angle. The Alignment field defines how the text is to be angled. There are eleven possible settings for this field. Normal
The text string will be displayed horizontally using the offsets to position the text relative to the point.
Angled
The text string will be displayed at angle which is defined in the Angle field. If the point has an angle dimension, normally A, this will override the value in the angle field.
Parallel
The text string will be displayed using the direction of the two feature string segments on either side of the point. The calculated angle will be weighted such that it is closer to the angle of the longer of the two feature segments. Only the Y offset value is used to position the string and the text will justified about the bottom centre of the text.
Parallel Leading
The text string will be displayed using the same angle as that of the feature segment leading into the point. Both offsets will be used and the text will justified about the bottom right of the text.
Parallel Trailing
The text string will be displayed using the same angle as that of the feature segment trailing after the point. Both offsets will be used and the text will be justified about the bottom left of the text.
Perpendicular
The text will be displayed using the perpendicular directions of the two feature string segments on either side of the point. The calculated angle will be weighted such that it is closer to the perpendicular angle of the longer of the two feature segments. Only the X Offset value is used and the text will be justified about the middle left of the text.
Perpendicular Leading
The text string will be displayed using the perpendicular angle of the feature segment leading into the point. Only the X offset will be used and the text will be justified about the top left of the text.
Perpendicular Trailing
The text string will be displayed using the perpendicular angle of the feature segment trailing after the point. Only the X offset will be used and the text will be justified about the bottom left of the text.
Centred Parallel
The text string will be displayed using the angle of the feature segment trailing after the point. Only the Y offset will be used and the text will be justified about the bottom centre of the text. The text will also be positioned half way along the feature segment that is trailing the point.
Centred Perpendicular
The text string will be displayed using the perpendicular angle of the feature segment trailing after the point. Only the X offset will be used and the text will be justified about the middle left of the text. The text will also be positioned half way along the feature segment that is trailing the point.
First and Last
Text strings will only be displayed on the first and last points of a feature. For the first point, the text will be displayed as though it is Parallel Trailing. For the last point, as though it is Parallel Leading.
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Point Code Prefixes and the Code Table
Normal
Angled
Parallel
Parallel Leading
Parallel Trailing
Perpendicular
Perpendicular Leading
Perpendicular Trailing
Centred Parallel
Centred Perpendicular
First and last
The Position field can be used to define where the text is to be placed relative to the point. It only applies to the Normal and Angled alignment options. The indicated position is not the justification point for the text. In fact, it is the opposite. For instance, if text is to be placed to the top right of the point, the text will be justified about the bottom left of the text. The X and Y offsets are not always used and will be made negative for certain positions.
Text String Macros The string of text that is displayed is defined in the Text field. This string does not have to be a simple string such as LP. It can contain macros which allows for the extraction and formatting of point co-ordinates, attributes and dimensions. Simple mathematical expressions can also be used in these macros and the string can also be displayed on more than one line. Examples of this where you wish to display the co-ordinates of specific points, the display of both the cover and invert levels of a manhole is required or the information relating to trees, such as types, spreads, boles and heights. A macro in a text string is signified where part or all of the text starts and ends with a percentage character, %. There must be one of these at each end of each macro for it to be recognised in the form %macro%. With one exception, anything that is not inside a macro is assumed to be normal text. The exception is where you wish to display text on more than one line. A new line can be requested by using the character par \n. The simplest form of a macro extracts an attribute or a value from the current point. The value that is to be extracted is defined in the macro by a label, which should always be lower case. The following macro labels can be used. px
This label will extract the easting co-ordinate of the point.
py
This label will extract the northing co-ordinate of the point.
pz
This label will extract the height co-ordinate of the point.
pc
This label will extract the code of a point. Note that any comma codes assigned to the point will not be included in the display.
pn
This label will extract the number of a point.
pp
This label will extract the point code prefix that has been used in the point code.
ps
This label will extract the string number that has been used in the point code.
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n4ce Manual pd
This label will extract a plan distance between two points. The distance displayed at a point is that between the current point and the next point in a feature. It is particularly useful when displaying the spread of a tree that has been surveyed and displayed using a two point symbol.
pdz
This label will extract a vertical difference between two points. The difference displayed at a point is that between the current point and the next point in a feature. If the next point is higher, the value displayed will be positive.
pg
This label will extract a gradient between two points. The gradient displayed at a point is the gradient from the current point to the next point in a feature. If the next point is higher, the gradient will be positive. The gradient that is displayed is always in the percentage form and if you wish to display a percentage sign, follow the current macro label with an empty label, two % characters.
pb
This label will extract a whole circle bearing between two points. The bearing displayed at a point is that between the current point and the next in a feature. The bearing will be formatted using the current settings for angle display.
pt
If you are using a macro to display text next to a station, this label is used to extract the type of station, such as Fixed, Known, Derived or Adjusted. It cannot be used for normal points
rem
This label is used to extract the remark from the current point.
If a label other than those described above is found or is upper case, it is assumed that it is a dimension name and the appropriate dimension value will be extracted from the point. When displaying co-ordinate values or lengths, n4ce will format the text to use the number of decimal places used for the display of lengths. However, you can override this or define the number of decimals for the display of dimension values. This is performed by preceding the label by a decimal point followed by the number of decimals. For instance %.3px% will extract and format the easting co-ordinate using three decimal places. If no decimal places are defined for a dimension, the dimension string is displayed as is with the exception that any superfluous zero characters are removed from the end. If you require that a co-ordinate or dimension is only displayed as a whole number, set the required number of decimal places to zero, for example %.0H%. You can also make a dimension negative by including a minus sign at the beginning, for example %-.3D%. You can specify that a simple mathematic calculation is carried out in a macro by surrounding the expression in round brackets. The expression will have two elements separated by one of the four mathematical operators +, -, * or /. The two elements can be co-ordinate labels, dimension names or numerical values. The opening bracket can also be preceded by a specification for the number of decimal places. The text macro %.3(pz-V)% will take the value of a dimension named V away from the height of the point and display it to three decimal places. If the number of decimal places is not defined, n4ce will assume the number of decimal places used to display lengths.
%.3px%E\n%.3py%N%.2pz%H
FW\nCL=%.2pz%\nIL=%.2(pz-V)%
%pc%\nS=%.1S%\nH=%.0H%
The examples above show how the text macros can be used to display co-ordinate information at a station or an important point, information about a manhole that has been surveyed or information about a tree that has been surveyed. If a text macro calls for the display of a dimension, or its use in a simple calculation, and the dimension has not been assigned to the point, n4ce will look for a default value in the fields of the current code prefix. If no default value is found, then one of two things can happen depending on whether the Accept Black Fields check button is ticked. If the button is ticked, n4ce will display the line without the macro. If the button is not ticked, n4ce will not display the whole line containing the macro, regardless of other macros or text that are present on that line.
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Point Code Prefixes and the Code Table The Display of Shapes The fifth page of the code prefix property sheet is called Shape and an example of this is shown below. A shape feature is a very simple graphical object, such as a circle or a rectangle, and is constructed using the co-ordinates of a small number of points. They are most commonly used for street furniture such as post, poles and manholes. The fields in the page allow you to define how any shapes that are required for a feature using the current code prefix are to be displayed. The Enabled check button allows you to specify whether a shape will be displayed or not. If it is ticked, a shape will be displayed using the parameters in the dialog. If not, the fields in the property page will be disabled. The Layer, Line Style and Pen fields define the graphic attributes that are to be used. The Fill Style field defines a fill style that could be used to fill the shape of the screen. When the fill is exported to an AutoCAD DXF file, it is exported as a solid hatch using the foreground colour of the fill style. The Type field defines the type of shape to be created and these are described in the following sections. There are various check buttons and these will be discussed with the shape types to which they are relevant. Some of the shapes require a dimension that provides a size. If the dimension is not attached to one of the points of the shape and there is no default provided in the fields of the code prefix, a value of 1.0 is assumed. The Retain Dimension check button can be used to remember a dimension. If this button is ticked, the value previously used will be remembered for each shape until a new dimension value is assigned. The Hide Second Points check button is also enabled for all multi-point shapes. If this is ticked, only the first point used for each shape will be displayed regardless of the point display settings. Also, any text or annotation on the second or subsequent points will not be displayed. The following sections describe how groups of points are used to construct the various types of shape. Examples of each type of shape are given indicating, where appropriate, the dimensions required for the shapes construction. For multi-point shapes, the expected order of the points is also defined. The function of the check buttons that have not been described above is also defined where relevant.
Circular Shapes There are seven methods of displaying circular shapes. The first three of these create a circle from one point together with an additional dimension. 1 Pt Circle
This option creates a circle from a surveyed centre point and a measured radius. The radius of the circle is provided in the Radius dimension, normally R.
1 Pt Diameter
This option creates a circle from a surveyed centre point and a measured diameter. The diameter of the circle is provided in the Diameter dimension, normally D.
1 Pt Circumference
This option creates a circle from a surveyed centre point and a measured circumference or girth. The circumference of the circle is provided in the Circumference dimension, normally C.
1 Pt Circle
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1 Pt Diameter
1 Pt Circumference
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n4ce Manual The Adjust Survey Distances check button also applies to circles that can be constructed from one point. If this button is ticked, the value of the radius of the circle is added to the observed distance during the survey reduction process. If this button is not checked, the displayed point will not be adjusted so that it is in the centre of the circle unless you also specify a distance offset dimension, normally H. This check button removes the need to duplicate information by providing a means of calculating a radius and the distance offset dimension, both of which are the same value. The Alternate Points check button also applies to the circles that can be constructed from one point. As the name suggests, this option allows you to only display a circle on every other point. An example of this is a where a tree has been surveyed using two points, the first on the trunk and the second on the edge of the canopy. If you want to use a one point circular shape to show the size of the trunk, this stops the display of a second trunk at the canopy edge. Four further method create circular shapes from two or three points. 2 Pt Circle
This option creates a circle from a surveyed centre point and a second surveyed point anywhere on the circumference of the circle.
2 Pt Diameter
This option creates a circle from two points on the circumference of a circle. The points will be assumed to be diametrically opposite each other.
3 Pt Circle
This option creates a circle from three points. Each of the points should be on the circumference of the circle.
3 Pt Arc
This option creates an arc from three points. The arc will be drawn from the first point to the third whilst passing through the second. This type of shape is often used in building elevation surveys to represent arched lintels above doors and windows.
2 Pt Circle
2 Pt Diameter
3 Pt Cricle
3 Pt Arc
Rectangular Shapes There are seven methods of displaying rectangular and square shapes. 2 Pt Rectangle
This option creates a rectangle from two points which should represent one of its sides. The width of the rectangle is provided in the Width dimension, normally W. If the width value is positive, the rectangle will be created to the right of the two points.
2 Pt Rect Cent
This option creates a rectangle from two points at either end of one of its axes of symmetry. The width of the rectangle is provided in the Width dimension, normally W. The sign of the width dimension makes no difference to the rectangle construction.
3 Pt Rectangle
This option creates a rectangle from three points. The first two points represent one of its sides. The width of the rectangle is calculated as the perpendicular offset of the third point from the line joining the first and second points.
3 Pt Rect Cnt
This option creates a rectangle from three points. The second and third points represent one of its sides. The width of the rectangle is calculated as twice the perpendicular offset of the first point from the line joining the second and third points
2 Pt Ortho Rect
This option creates a rectangle from two points which represent a diagonal. The rectangle is always orthogonal in the current co-ordinate system so the sides will be generated east-west and north-south. This type of shape is used in building elevation surveys to represent doors and windows
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Point Code Prefixes and the Code Table 2 Pt Square
This option creates a square from two points which represent one of the sides of the square. The square will be created the right of the two points.
2 Pt Diag Square
This option creates a square from two points which represent one of the diagonals of the square
2 Pt Rectangle
2 Pt Rect Cent
3 Pt Rectangle
2 Pt Ortho Rect
2 Pt Square
2 Pt Diag Square
3 Pt Rect Cent
The Open Rectangle check button applies to the 2 Pt Rectangle and 3 Pt Rectangle options. If ticked, the side of the rectangle that is opposite the side created by the first two points will not be displayed. An example of where this may be used is where a rectangular conservatory has been added to the side of a house.
Triangular Shapes There are three methods of displaying triangular shapes from either two or three points. 2 Pt Triangle
This option creates an isosceles triangle from two points which represent its base. The height of the triangle is provided in the Width dimension, normally W. If the width is positive, the triangle will be created to the right of the two points.
3 Pt Triangle
This option creates a triangle from three points each of which represents one of the apexes of the triangle.
2 Pt Eq Triangle
creates an equilateral triangle from two points which represent one of the sides. The third apex will be calculated to the right of of the two points.
2 Pt Triangle
3 Pt Triangle
2 Pt Eq Triangle
Other Shapes There are two other shapes that can be displayed. 2 Pt Line
This option creates a line segment from pairs of points which represent the start and end of the line. This is similar to the line feature option where alternate segments of the feature are displayed.
4 Pt Polygon
This option creates a closed quadrilateral from four points each of which represents one of the apexes of the polygon.
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n4ce Manual Sub-Dividing Rectangle and Polygon Shapes Dimensions are available that instruct n4ce to sub-divide certain shapes into sections. This can be used to simulate steps, large manholes with multiple access covers, cattle grids and gratings. The Number of Segments dimension, fixed as NS, can be used to sub-divide any two point rectangles, normal three point rectangles or four point polygons with additional lines. For a two point rectangle, the lines are perpendicular to the two points, as though the first and second points are the top and bottom of a flight of steps, respectively. For a three point rectangle, the lines are parallel to the first two points, as though the first two points represent the bottom of the steps and the third is the top. For the four point polygon, the sides between points 2 and 3 and 4 and 1 are sub-divided.
The value of the NS dimension is the number of segments that the shape is divided into. Therefore, the number of additional lines that are drawn will be one less than this value. The examples above show shapes with an NS dimension of 3. The Number of Columns dimension, fixed as NX, and the Number of Rows dimension, fixed as NY, can also be used to divide two point and normal three point rectangle shapes above in both directions. The columns are always assumed perpendicular to the line between the first two points and rows are parallel to that line. The number of columns and rows dimensions should always be applied to the first point on the shape.
The examples above show shapes with an NX dimension of 3 and an NY dimension of 2. Note, that you do not need to provide both dimensions should you only want either columns or rows. Looking at both sets of examples above, you should see that for the two point rectangles the dimensions for the number of segments and for the number of columns are the same. However, for the three point rectangle, the number of segments dimension is the same as that for the number of rows.
The Display of Point Annotation Some of the attributes of each point can be displayed as point annotation text where the text can be extracted and formatted. The items of annotation that can be displayed are the point height, the point number and the point code, which does not include any comma codes attached to the point. Control of the display of these items is handled using the sixth, seventh and eighth pages of the code prefix property sheet. These are called Height, Number and Code and an example of the Height property page is shown to the right. Generally, the fields perform the same purpose as those for feature text with a few exceptions. The Prefix and Suffix fields are available for all three types of annotation and these allow you to add additional text before and after the annotation item. For instance, when displaying the level of a manhole cover, this may be formatted as CL19.683m by entering CL in the prefix and m in the suffix.
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Point Code Prefixes and the Code Table The Display of Heights There are three fields in the heights property page that do not appear in the property pages dealing with numbers and codes. The Always Plot Point check button allows you to override any settings for point display. If the layer for the points associated with the current code prefix is turned off and this check button is ticked, the point will still be displayed. If this setting is set when exporting to an AutoCAD DXF file, the layer used for the point marker will be the same as that for the height text. The Decimals field allows you to define the number of decimal places that are used to format height text. This allows you to vary the number of decimal places for heights depending on the accuracy of the points. The Priority field is used when filtering height annotation. There will be situations where height text strings overlap each other and there is an option that allows for such strings to be filtered. This field defines the priority of a height text string should an overlap be found. The field can be set to a value of always or a numerical value of 9 down to 1. If the field is set to always, no filtering takes place on height text using the current code prefix. If set to a numerical value and an overlap is found, the text string with the lower priority will be removed. If the priorities are the same, neither is removed. There is also an option that does not remove the heights but instead, places the appropriate points onto the point list.
Code Prefix Fields and Default Dimensions There are times when you wish to define default values for one or more dimensions that are associated with a point. This list of dimensions can also be used when exporting the code prefixes so that they can be loaded onto survey instruments and taken into the field where the surveyor will be asked to enter the required dimensions for a particular code. The dimensions could be one of those already described in this chapter or it could be another dimension that is required for information purposes such as the depth of a manhole or species of a tree. The ninth page of the code prefix property sheet is called Fields and this allows you to do this. When selected, the property page shown below will be displayed. The Fields group displays the available dimensions and allows you to add and remove them from the current code prefix. The Dimensions list shows the dimensions that have already been added. To add a new dimension, select the Add button and you will asked to enter the new dimension name. To remove a field, select it in the list and select the Remove button. After a check is made, the dimension will be removed. As you select each dimension, the fields in the remaining parts of the property page update themselves automatically. The Default field in the Data group allows you enter a default for this dimension. This value will be used if no dimension has been attached to a point using this code prefix. The Attributes groups contains the basic description of what the dimension represents. The Type field specifies the data that is expected in the dimension. As far as n4ce is concerned, this setting is irrelevant as it is only interested in the dimension value itself. It is up to you what you do with the dimension in terms of text macros, etc. It does, however, have an effect when you are exporting the dimension in files of codes for upload to survey instruments. Real
A number which may or may not have a decimal point.
Integer
A whole number which does not have a decimal point. These are often used as counters.
String
A string of text which contains alphanumeric and other characters.
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n4ce Manual The Description field allows you to enter a description for the dimension. When a dimension is added, the description will have the same name as that of the dimension. The three radio buttons are used to constrain the value of the dimension and are described in the next section. The Must Exist check button allows you to specify that a dimension is definitely required at a point. Nothing is actually done if it does not exist. When carrying out a feature code report and a dimension of this type is found to be missing, it is flagged up in the report.
Constraining Dimensions As well as defining the data that is expected, n4ce also allows you to define constraints for dimensions. Again, these settings are irrelevant in n4ce but are used for setting up code lists for instruments. The three constraint settings are as follows. Normal
which is a normal dimension with no constraints. An example of a normal dimension is shown in the property page above.
Ranged
which is a dimension where you can define maximum and minimum values for a dimension. The value of the dimension is not checked against the maximum and minimum values by n4ce but these constraints may be used by your survey instrument. For this type of dimension, most survey instruments will expect a real value.
Choice List which is a dimension chosen from a list of available options. Again, the value of the dimension is not checked by n4ce to ensure that one of the options has been chosen. For this type of dimension, most survey instruments will expect either a real or string value.
The Display of Multiple Graphic Elements Each of the graphic elements that can be displayed as part of a feature string has now been described. It is obvious that you can display points, text and point annotation on any feature. However, you can also combine lines, symbols and shapes together. In this section, there are examples of some of the more common situations where multiple graphic elements are displayed.
Tree Canopies and Trunks It is seldom the case that the trunk of a tree is directly proportional to its spread and, therefore, you should not use a symbol which incorporates a trunk. To achieve the correct size for both trunk and spread, a combination of a symbol representing the canopy and a circle representing the trunk is required. The Symbol property page should specify the symbol representing the tree canopy. The type can be either a one or two point scaled symbol. If you set the type to be a one point scaled symbol, you will need to provide
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Point Code Prefixes and the Code Table a symbol scale dimension or assume a default from the fields. If you set the type to be a two point scaled symbol, as shown to the right, the distance between the two points defines the scale. You would also normally use the option to hide the second point as this will stop any point marker or annotation being displayed there. Some users have set up a series code prefixes for trees with each representing a tree of a given size. Each code prefix has a one point scaled symbol enabled and a default value for the spread in the fields. The tree spread is indicated in the code prefix, for instance TE01, TE02 and so on. The Shape property page should be configured to display a one point circle using whichever of the radius, diameter or circumference types that you prefer. This value will have to measured and entered into the data logger or taken from a default in the fields. If you have specified the canopy type to be a two point scaled symbol, the option to display the circle at alternate points should also be enabled so that only one trunk circle is displayed for each tree. In this case, care should be taken when using the option that adjusts the surveyed distances by the radius of the trunk. If you are using a two point symbol, there should not be a default for the radius, diameter or circumference dimension, or at least it should be set to 0.0. If there is a default with a value, the offset will be applied to both of the points and whilst the aim to adjust the trunk point is achieved, the canopy point will also be shifted by the same amount. However, since tree canopies are generally indicative of size, the error introduced may be acceptable. When displaying trees, you will often choose to display text. If the Hide Second Point check box is ticked, the text will only be displayed at the first point. The use of macros described eariler in this chapter enables you to display multiple lines including the height, speard, trunk girth and tree species.
Gullies and Kerb Channel Lines There are often gullies along a kerb channel line. However, when surveying the channel line, the number of gullies is usually not enough to accurately reflect the shape of the channel line. A combination of a line feature and the ability to plot a symbol when it is necessary is required.
The Line property page should be set to display whichever line style is required. The Symbol property page should be set to display the symbol required for a gulley. Since the symbol is not required at every point, the symbol type should be set to a one point request symbol. When needed, the symbol is generated using the same method as that for a one point aligned symbol. The request is made by assigning the symbol request comma code, normally S, to the point on the channel line.
Overhead Wires In rural areas, electricity and telephone wires are often suspended overhead from wooden poles. To create a graphic representation of this, you could use a line to represent the overhead wire and a single point circle to represent each pole. An item of feature text next to each pole will signify what the wires are for.
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n4ce Manual You will not always be able to survey these points at ground level so they can be used in a ground model and a reading is taken further up the pole. In this case, you should consider using the option not to model points in the Point property page. If you do not use this option, you may have to add the comma code to exclude the required points from the model.
In the Line property page, you can set the required line style. For overhead wires, there is a line style called OH Power which is designed for this situation. In this example, none of the check boxes in the Attributes Group should be checked. These may adversely affect the display of the feature but also the formation of the triangles. The Text property page can be set to display a text string next to each pole. For instance, you could use EP if you are surveying electricity wires or TP if you are surveying telephone wires. The Shape property page should be set to display one of the single point circles. Because electricity and telegraph poles tend to be the same size, a default value for the radius, diameter or circumference should be set up in the Fields property page. You can use the option that will adjust the surveyed distances by the radius of the pole so that you do not need to provide the distance offset dimension. Some clients will prefer a post to be shaded so use a fill style using the solid fill pattern with the required colour. In this case, you should consider using the point style called None.
Code Import Conventions With some survey instruments and data loggers, it can be time consuming to add comma codes and dimensions. It is much easier to append all the information about a point to the code using a space character as a delimiter. There are a number of code import conventions supported by n4ce. The first code import convention is None. This states that the code is simply the code and that if any comma codes have been added to the code, they use a known character to separate them from the main point code. The second code import convention is AiC (Dim Labels). This states that the first string is the code and that the second and subsequent strings represent comma codes and dimensions. Each dimension is represented by a pair of strings, the first giving the dimension name and the second the dimension value. If there are an odd number of strings following the point code, the first of these are the comma codes that are to be assigned to the point. Look at the two examples of code strings given below. TR01 S 5.0 R 0.5 TR01 X S 5.0 R 0.5 Both of these would assign a code of TR01 to the point. They would also both assign dimensions of S=5.0 and R=0.5 to the point. However, the second would also assign a comma code of X, to the point and the code would be displayed as TR01,X in n4ce.
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Point Code Prefixes and the Code Table The third code import convention is AiC (No Dim Labels). This is very similar to the above except that the names of the dimensions are not stated. Instead, n4ce will assume a name of I1 for the first dimension, I2 for the second and so on. The lack of dimension names means that whether there are an odd or even number of strings following the point code is irrelevant. For this option it is assumed that if the first string contains alphabetic characters, it is the string of comma codes. If it does not, it is the first dimension. Again, look at the two examples of code strings given below. TR01 5.0 0.5 TR01 X 5.0 0.5 These codes would have the same effect as the codes given in the previous option except that the dimensions would be I1=5.0 and I2=0.5. The fourth code import option is GeoSite. A number of users define codes in the field using the GeoSite format. This is actually very similar to the previous option. The only difference is that when wishing to start a new string, the comma code used is always S rather than the N normally used in n4ce.
Hash Codes There are times when a single survey observation needs to be used for more than one feature. For instance, there may be a number of underground services meeting in an access manhole or the start point of an embankment where the top and bottom are the same point. In n4ce, you can only assign one code to a point so where an observation is to be used more than once, duplicate points must be created. In the field, you can use hash codes to define multiple codes for a point or observation. A hash code is a code string where multiple codes are separated by the hash character ‘#’. When a point that has a hash code is imported into n4ce, the multiple codes are extracted. A copy of the point or observation is then created for each of the extracted codes. If we take the example below, two points or observations will be created. The first will be code as TB01 and the second BB12. TB01#BB12 Note that codes that are separated by the hash sign all need to follow the current code import convention. Therefore, you can assign different comma codes and dimension values to the copies of the points that are created. In the example described above where a number of pipes enter and leave a manhole, you can assign a dimension to each code specifying the appropriate pipe diameters.
Importing and Exporting Code Prefixes At the top of the Code Prefix Dialog Box, there is a menu bar with three options. The File menu has already been described but there are two further options, Import and Export. The options on these menus allow you to load code prefixes from and save code prefixes to other file formats used by survey instruments.
Importing Code Prefixes When importing code prefixes, you will be asked whether you wish to overwrite existing prefixes should they exist. If you answer yes, the existing prefix will be removed from the current settings and replaced by the details found in the imported file. If you answer no, the details in the imported file will be ignored. Whichever option is used, an open file dialog is displayed and you are asked to select the file to import. There are three import options available. The two Leica options allow you to import from Leica IDEX files and from Leica HeXML files. When you download survey information from a Leica DBX database using the HeXMLPC utility, the code prefixes in the DBX file are also included in the XML file. The Trimble option allows for the import the code prefixes from Trimble FXL files. If there are attributes attached to any of the code prefixes in the files, n4ce also reads them in and you will see them as fields attached to the appropriate code prefix.
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n4ce Manual Exporting Code Prefixes When exporting code prefixes, all the prefixes in the current project will be exported to the file. The Leica options allow you to export to Leica IDEX files and Leica HeXML files. When exporting to IDEX files, you will be given the option to specify which version of the IDEX file you wish to create as different instruments require slightly different IDEX files. The Topcon options allow you to export to a Topcon XML file or a Topcon FCL file. The Trimble options allow you to export the code prefixes direct to a survey instrument or to a Trimble FXL file. Both of these options use the Trimble Link Engine which should be installed on your computer. If you do not have this program, please visit the Trimble website and download it. You will have to register with Trimble to use it.
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