Discover 2012 Tutorials

Encom Discover 2012 TM

TUTORIALS

Table of Contents

Table of Con tents 1

Map Making Tutorial ................................................................................ 1 Professional Quality Map Production .................................................... 1

2

Register Raster Image Tutorial ............................................................ 15 Geo-register Image ................................................................................ 15

3

Drillhole Display Tutorial ...................................................................... 23 Display and Output Drillhole Sections ................................................ 23 Data Sources .......................................................................................... 23 Preparing Data Prior to Viewing Drillholes ......................................... 23 Creating Sections .................................................................................. 28

4

Create Gridded Surface Tutorial .......................................................... 55 An Exercise in Surface Modelling and Analysis ................................ 55

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Conventions in this manual

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Conventions Used in this Guide Certain conventions are used throughout this manual: •

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Keys on the keyboard appear in small capital letters. For example, the Ctrl key appears as CTRL in the text. Menu options, buttons, and dialog labels are in boldface. For example, “On the Discover menu, Discover menu, click Exit.” Exit.” The shorthand form menu>submenu>item indicates the menu path to an option. For example, “Select Discover>Configuration... ” Is equivalent to the instruction “On the Discover menu, Discover menu, click Configuration” Configuration ” References to other sections in the documentation are italicised. For example, see Data Utilities. Utilities. File and folder names and paths are shown enlarged and monospaced. For example, disk:\Documents and Settings\username\Desktop. Options that you select from a list are shown enclosed by < > symbols. For example, “Click the Projection button and select .”

Map Making Tutorial

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1

Map Making Tutorial The objective of this tutorial is to create a professional professional quality map for presentation purposes. This tutorial takes you through the steps required to produce a geological map, complete with a location map, legend and titleblock ready for printing. Note:

The tutorial dataset is installed in either of the following locations:

..\\Program Files\MapInfo\Professional\Discover\Discover_Tutorial (on Windows XP operating system) or

..\\ProgramData\Encom\Discover\Discover_Tutorial (on Windows Vista or 7 operating systems) All references references to the dataset dataset locations locations in the tutorial tutorial exercises exercises ignore ignore the pathing pathing up to \Discover Tutorial. B5

Professional Quality Map Production Step 1 - Open Map Layers Step

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1.

Note

Navigate to Discover>Configuration... and ensure the CommandSearch is set to automatically start by placing a check in the box. The Command Search is a search tool which opens in the top right corner of the MapInfo Professional session window. This enables the quick keyword navigation to tools within MapInfo Professional and Discover. Alternatively, Alternatively, tools can be opened through the traditional menu interface. Throughout Throughout the following exercise note all tools can be access by the Command Search by typing keywords or the tool name.

Navigate to the Command Search and type in ; select from the item list.

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Discover Tutorials

Open the following tables in a single Mapper Window from the folder \Discover_Tutorial\Map Making:

GEOLOGY,STRUCTURES,MINERALS and TENEMENTS 2.

With the Layer Control open, check the order of each table. Make sure the tables are organised as followed (top to bottom in terms of visibility): MINERALS, STRUCTURES, TENEMENTS and GEOLOGY. If the order is incorrect, move the layers with the arrow buttons at the top the layer control frames.

3.

Complete the map window set-up by selecting the Zoom to all layers button from the ELC or by choosing Map>View Entire Layer>All Layers. Layers . Double left mouse click on the ELC title bar to roll the window up to allow more workspace when it is not required.

Step 2 –Annotate Linework Step

B31

The STRUCTURES layer contains syncline (green lines), anticline (brown lines) and fault (black lines) structures. Using Discover, these lines can be modified easily to include their respective fold axis annotations. annotations. 4.

Make the STRUCTURES layer editable and select an anticline line object. Select all the other anticline lines from the STRUCTURES layer using the Discover>Map Window>Select by Graphical Styles . Click the Get Selected Object Style button.

Map Making Tutorial

Select object based on style

5.

To modify the selection to include anticline annotations, navigate to Discover>Map Making>Line Annotation, Annotation , and fill in the following options:

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Discover Tutorials

Annotating the selected lines with Anticline symbols

The annotation is written to the STRUCTURES layer. Repeat the above process for the syncline lines, annotating them with a syncline symbol. Note

If you are applying a directional symbol, such as normal fault, it is important that the annotation appears on the correct side of the selected line. A symbol is placed to the left of a line or facing up if the Facing left/up box is ticked. If the box is not ticked, the annotation appears appears on the right or down side of the selected line.

You may wish to experiment with this feature using some of the other lines in the STRUCTURES layer e.g. Faults. To manually place a symbol on a line, select the line, open Discover>Map Making>Line Annotation, Annotation , and select the Annotation Placement option Place with cursor . After pressing OK a tool button will appear to use. 6.

Save changes made to the STRUCTURES table, navigate to File>Save Table. Table.

Map Making Tutorial

Step 3 – Add Text Labels Step

B41

Adding labels labels to a map for printing printing requires a methodical methodical approach approach to get the the required result. result. If you place labels on the map window and print, the labels often have an inappropriate size and require additional manipulation. Discover solves this problem by allowing you to label a map layer at a set point size at the scale at which the map is plotted. 7.

Click on the Text Labels button or navigate to Discover>Map Making>Label Creator to Creator to open the Label Creator dialog. Creator dialog.

Adding Text Labels dialog

8.

From the Label Creator dialog Creator dialog box, select the layer from the Table pull-down list and field from the Column pull-down list. Leave the style as the default Arial; specify label size <10> pts select the Map Scale radio button and make Map Scale 1 to <15,000>. Select the Table radio button in output, and accept the default table name and location Discover_Tutorial\Map making\Tenements_Labels.tab. Click Generate

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Discover Tutorials

Step 4 - Creating a Map Legend Step

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A custom legend legend can be created using Discover Discover with the layers, columns columns and order order of individual legend fully customisable. customisable. 9.

Click on the Legend button or navigate to Discover>Map Making>Create Map Legend to open the Create Legend 1 dialog.

10.

Select the MINERALS, STRUCTURES and GEOLOGY tables by holding the CRTL key while left clicking on the relevant tables. Click OK. OK.

11.

The Create Legend 2 dialog allows you to specify which columns of attribute data should be displayed in the legend. Fill in the Create Legend 2 dialog box as follows:

Generating a legend for the geology map

12.

Click in the Specify Order boxes Order boxes for the MINERALS and GEOLOGY tables to set the order of legend items for these layers. If your map window does not display the full extents of a table, and you want a legend created for all items in the table, do not place a tick in the box for Legend for Legend from objects in map window only. only.

13.

To specify the font size for the legend text, click on the Styles button and select the font style button next to Title Line. Line. Choose point size <24>. Repeat the process for Sub-Title for Sub-Title Line and choose point size <18>. Click the Text Line 1 and Text Line 2 font style buttons and choose point size <14>. Click the OK button and enter the table name when prompted into the folder \Discover_Tutorial\Map Making. Click the Save button.

14.

The legend order window for the MINERALS layer will be displayed first. The minerals should be displayed in Alphabetical order (ascending), (ascending) , select the appropriate appropriate option, and click OK. OK.

Map Making Tutorial

15.

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A second legend order window will be displayed for the GEOLOGY layer. The lithologies need to be organised into chronological order. Notice that lithologies rather than ages are displayed. Discover orders legend items based on the first column chosen in the initial setup dialog box. Therefore, to display lithology by age in the geological legend, it is necessary to determine the relevant order prior to starting the legend process. Alternatively, Alternatively, the Look-up code from Geology option allows the lithology to be ordered using a numerical attribute. To place the lithologies in chronological order, reorganise as shown in the following dialog. Use the Custom setting and the Up and Down buttons to move items accordingly. Click OK when finished.

Re-ordering legend entries for the Geology layer

16.

The geological legend will be displayed in a new map window. You may wish to verify the lithology is in the correct order by displaying the geology browser. Minimise the legend window and make the geological map window active before proceeding to the next step.

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Discover Tutorials

Step 5 - Generating Scaled Hardcopy Output Step

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The Scaled Output tool can produce a professional looking map output into a MapInfo Professional layout window. Map grids, titleblock, scale bar and legend layers can be added to the scaled output. 17.

Ensure that the MapInfo Professional Layout Window is set to the size and orientation required. From the MapInfo Professional menu bar, navigate to File>Page Setup, Setup, select and click the Landscape button. Click OK to accept the Page Setup parameters.

18.

Click on the Scaled Output button or navigate to Discover>Scaled Output to open the Scaled Output dialog. Under Map Under Map Scale choose (bottom of the scale list) and type <15,000> into the text box.

Scaled Output Configuration dialog

19.

Under Frame Under Frame Setup, Setup, choose (bottom of the frame list) from the list of frame settings. On the Scaled Output - Configuration dialog box, choose and click the Landscape button. Notice that the map frame position measurements change to reflect the area that the map covers on your selected sheet of paper. For this exercise, you will place a titleblock and legend outside the map frame. If you choose size paper, decrease the map frame position width to <22.7> cm. Leave the frame height at <19.0> cm.

Map Making Tutorial

9

Click the OK button and enter a name to save the setting indicating A4 landscape paper, legend and titleblock outside map frame. The non-printing margins may have to be adjusted depending on the printer driver in use. You can determine if adjustment is required by completing the scaled output exercise and observing the resulting layout window. If some portions of the map are in the light grey area (non-printing margins) of the layout, you will need to return to the Configuration menu and adjust the non-printing settings. If a non-printing margin is changed (say right and left edges from 1 cm to 1.5 cm each), this needs to be compensated for by decreasing the frame width by 1 cm (0.5 cm added to each edge).

Note

20.

Return to the Scaled Output dialog, ensure that the Draw Grid option is ticked, TitleBlock and Scalebar are selected. Click the Preview button.

Scaled Output Dialog

21.

The map window will render a transparent polygon, representing the area to be plotted at 1:15,000 1:15,000 scale. If you are not satisfied satisfied with the scale chosen chosen respecify another scale and select Preview again to view the changes. When you are satisfied click OK. OK.

22.

In the menu bar at the top of the screen you will see Scaled Output Appear, you can now left click on the frame in the map window and position it as needed. Drag it to cover the TENEMENTS and GEOLOGY layers. When satisfied with the frame position, select the Scaled Output>Accept Map

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Position menu option. The map window resizes to the area of the transparent map frame. The Overlay Map Grid dialog box appears. Click OK to accept the default parameters. A grid is drawn into the map window. 23.

The TitleBlock and ScaleBar Options dialog box opens. Enter the following details: Title Line 1: 1: Title Line 2: 2: Title Line 3: 3: Author :

username >

From the Titleblock Position list, choose . The default ScaleBar position ScaleBar position is Show ScaleBar in Titleblock. Titleblock . You can also elect to show the scalebar in a separate map window or not display the scalebar at all. Other options give you the opportunity to list the layers of the map window in the layout. The default display position is . For the purpose of this tutorial, set the display to . Click OK to create the titleblock and a layout window containing the scaled map. Step 6 – Adding Scaled Legend Frame to Layout Step

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24.

Make the Geology Legend map window the front window. Click on the Add Scaled Frame button or navigate to Discover>Map Making>Add Scaled Frame to Layout and fill in the dialog box as below.

Map Making Tutorial

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Adding a scaled frame for the legend into the layout

The legend is added to the layout window. Paper measurements appear along the side of the layout window in centimetres. Take a moment to examine the legend position with reference to the layout measurements and the information that was entered in the above dialog box. This will help you understand how Add Scaled Frame to Layout works. For A For A size paper , enter a value of <21.9> cm for Offset for Offset from left. left . You can always adjust the position of the frame once it has been added to the layout. Step 7 - Creating a Location Map Step

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The final task is to add a location map to the final layout window. 25.

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Within the ELC right click and select the option. In the Open dialog select the table AU AUSTRALIA from the \Discover_Tutorial\Map Making folder and place it into a new map window (select from the Preferred View pull-down list). Next, create a red red rectangle to represent represent the location of the the map map within Australia. Select the Discover>Object Editing>Key In Shapes menu option. In the Key in Shapes dialog select the from the Draw onto pull-down list.

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Discover Tutorials

Choose the Rectangle object type and click on the Polygon object style button. Select the (No pattern) option and click on the Line object style button. Choose a line colour and a width of <2> pixels. XY Units are in decimal degrees. Click the Enter Coordinates button. Enter XY coordinate pairs as follows: Corner 1 Xm: Xm: <121.41> Corner 1 Ym: Ym: <-26.81> Corner 2 Xm: Xm: <122.98> Corner 2 Ym: Ym: <-25.52> Click OK and Close. Close. 28.

Choose Map>Save Cosmetic Objects to save the newly created rectangle to a table called in the folder \Discover_Tutorial\Map Making. AUSTRALIA using the zoom tool for the AU AUSTRALIA View the entire layer for AU layer in the ELC dialog.

Step 8 - Adding the Location Map to the Layout Window Step

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29.

Make the Location Area map window the front window. Select Map Making>Add Scaled Frame to Layout . Fill in the dialog box with the following parameters: Scale 1:

<120,000,000>

Frame width (cm): (cm) :

<5>

Frame height (cm): (cm) :

<4>

Offset from left (x cm): cm) :

<23.7>

Offset from top(y cm): cm) :

<0.95>

Position in Map Centre Easting: Easting :

<133.38>

Northing: Northing :

<-27.18>

The location map is added to the layout window.

Map Making Tutorial

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B02

Step 9 - Exit Scaled Output and Plot Map 30.

Select Scaled Output>Exit Scaled Output A dialog box box appears allowing you to save the map grid, titleblock, titleblock, scalebar scalebar and a workspace. If you want to plot more copies of your map later, you should tick all boxes and enter appropriate table names to save the titleblock, scalebar scalebar and map grid. If you do not save the tables and workspace you will have to go through the scaled output process again if you wish to re-create the map.

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Print the displayed scaled map by choosing File>Print. File>Print . An example map with titleblock, legend and location map is shown below.

Scaled map with titleblock, scalebar, legend and location inset

Register Raster Image Tutorial

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Register Registe r Raster Image Tutorial The objective of this tutorial is to show you how to register a raster image. If a raster image is simply opened into MapInfo Professional using File>Open, the image is displayed in non-earth coordinates. This means that you cannot overlay vector data captured in a real world coordinate system such as latitude/longitude or UTM coordinates. In order to display a raster image such as an aerial photograph or scanned geological map then the image must be “registered” i.e. assigned a real world coordinate system so it can be displayed in the correct geographical location. Raster images can be registered using MapInfo Professional or Discover. The Discover Images>Rectify Discover Images>Rectify Image tool is a powerful utility that enables the registration of raster images in geographic real-world coordinates. Unlike image registration registration using MapInfo Professional, the Discover Rectify Discover Rectify Image tool can register and modify images that have been stretched, skewed or rotated. This process, known as Rectification or Rubber-Sheeting enables portions of an image to stretched or warped to fit the entered control points. In order to register a raster image we need to identify a number of locations on the image for which we know the real world coordinates. These locations are called control points. At least 4 control points should be used to rectify a raster image and the control points should cover the extents of the raster image. Note:




Geo-register Image Step 1 - Open Rectify Image Dialog Step

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1.

Note

Navigate to Discover>Configuration... and ensure the Command Search is set to automatically start by placing a check in the box. The Command Search is a search tool which opens in the top right corner of the MapInfo Professional session window. This enables the quick keyword navigation to tools within MapInfo Professional and Discover. Alternatively, Alternatively, tools can be opened through the traditional menu interface. Throughout Throughout the following exercise note all tools can be access by the Command Search by typing keywords or the tool name.

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Discover Tutorials

Navigate to the Command Search and type in the ; select from the item list.

Rectify Image dialog with Load Image button selected

2.

Click on the Load an image file button and browse to the \Discover_Tutorial\Register Image folder and select the file.

3.

When the Loading Control Points dialog appears click No. No.


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The REGIONAL_GEOLOGY file should display in the Current Image window and the image can be viewed in a map window. 4.

Click on the Projection… button and change the projection to .

Choose Projection dialog

We now need to add a number of control points to the image for which real world coordinates are known. If the scanned image has a map grid (as our image does) then the intersections of this grid can be used as control points and the real world coordinates entered manually. If there is no coordinate information available available on the image then coordinate information may be extracted from vector data open in a map window such as road intersections, drainage convergence points, fence lines or property boundaries. Ideally control points should be placed throughout the entire image and the more control points (providing they are accurately placed) the better the final rectification.

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Discover Tutorials

Step 2 - Register the Image Step

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Make sure that you can see both the image in the map window and the Rectify Image dialog clearly. If you have dual monitors drag the Rectify Image dialog to the second monitor to free up screen space. Click on the REGIONAL_GEOLOGY map window and zoom to the top left hand corner of the image. We are going to add our first control point using the top left grid intersection. The more the image is zoomed when the control point is placed the greater the accuracy in the image registration.

Image map window zoomed to top left hand corner

5.

To add a control point, press the New Point button. A new line is added in the Ground Control Points window. Click on the Right Arrow icon to select this row.

6.

With the control point row selected, click on the Image button and move the cursor to the map window containing the image to rectify. The cursor is now displayed as a cross-hair (+). Click on the + control point location in the top left image map window where the 118º Longitude and -22º Latitude meet. The control point is added to the map window and labelled.


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The location of the X and Y pixel coordinates in the image are automatically updated in the control point Image_X and Image_Y cells. To remove control points use the Delete Point button. The last change applied to a control point row can be reversed using the Undo Change button. 7.

To specify the Map_ X and Map_Y coordinates make sure the control point row is selected. An icon will appear to the left of the row to indicate the selected row. Enter <118> into the Map_X cell and <-22> into the Map_Y cell. Note that –ve latitudes are required for the southern hemisphere.

8.

Follow the above procedure to add the remaining 3 control points: i.e. the top right, bottom right and bottom left of the image.

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Discover Tutorials

Image map showing control points and completed Rectify Image dialog

9.

If you need to modify the location of the control point on the image make _ImageControlPoints layer editable in the map window, drag the control the _I point to the new location using the cursor and then click the Sync Map>GCP button. The control point Image_X and Image_Y will be updated with the new pixel coordinate.

10.

When all the points have been added, click on the Rectify button, you will be prompted to save the control points, select Yes select Yes and the default file name. A Save As dialog will prompt for an output file name and location. By default the output rectified table will contain the original image file name with a _r _rectified suffix. The rectified image table is saved to the same folder as the original image.


Upon pressing the Save button, a status bar is displayed at the bottom of the Rectify Image dialog showing the rectification progress. When the rectified processing is completed, the rectified image is displayed in a new map window.

This registered image can now be used to digitize various map objects such as geological units or structural data.

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Discover contains a number of additional tools for working with images. These can all be found on the Images menu and include the following: •

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Reproject Image Reproject raster images into a new coordinate system. Image Properties View image projection, X and Y coordinate extents, number of rows and columns, total pixels, size on disk and in memory, image type and metadata. Enhance Image Adjust image image contrast and and brightness and modify modify colour and gamma Red, Red, Green, Blue channels. Filter Image Apply smoothing smoothing and edge detection detection filters to to image. Clip Image Clip a raster image to a region. Rotate Image Rotate image by specified angle Convert Image Save an existing image in a new image file format Modify Image Set image transparency and set a single colour transparent

The Discover Images Discover Images utility is compatible with BMP, JPG, PNG, GIF and TIFF raster image formats only. See Discover Reference Manual or Manual or Help Help for detailed information on each menu option.

Drillhole Display Tutorial

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Drillhole Display Tutorial This aim of this tutorial is to use the Discover Drillhole module to produce a series of cross-sections and a plan for inclusion in an assessment report. It covers the data formats required, procedures for creating sections and how to produce a section layout.

Display and Output Drillhole Sections Display

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Data Data Sources B9

The example drillhole data (collar, survey, lithology and sample data) used by this exercise has been entered in the field into a simple Microsoft Access database. database. The corresponding assay data has been returned from the laboratory in a Microsoft Excel format. Surface geology has been previously digitized and is in MapInfo Professional format. The dataset is a diamond drilling program conducted on a gold prospect, consisting of 11 holes totalling 1585 m. These files are located in the \Discover_Tutorial\Drillholes folder. The files are named DRILLING.MDB, AS ASSAYS.XLS and SURFACE_GEOLOGY.TAB. Note:




Preparing Data Prior to Viewing Drillholes Before drillholes can be viewed, the data has to be prepared as follows: •

Merge the Excel format assay data with the assay intervals in the Access database

•

Register the other Access tables in MapInfo Professional

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Create objects for the collar locations

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Generate a digital elevation model (DEM) from the collar elevations

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Discover Tutorials

Step 1 - Merge Sample Data and Assay Data Step

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1.

Note:

Open the Excel spreadsheet of assay data in MapInfo Professional by choosing File>Open and changing Files of type to , select file.

Enable the Create copy in MapInfo format for read/write . This will greatly speed the processing time in step 4 below. Press Open and select the box against Use Row Above Selected Range for Column Titles. Titles . The dialog should now display the worksheet range . Click OK. OK. A browser window opens displaying the columns SampNo, SampNo, Au, Au, As, As, Cu contained within this database. 2.

Open the Access database containing the sample data by choosing File>Open and changing Files of type to , select and click Open. Open. Select the table and click OK. OK. A browser window appears displaying the columns HoleID, HoleID, From, From, To and SampNo. SampNo.

3.

You have to modify the table structure of the SAMPLES table so you can append the assay information. Choose Table>Maintenance>Table Structure . Add the fields , and , all of type . Also, place a tick in the Index column for the field . Click OK. OK. Ignore any warning messages that appear regarding unsupported fields. Reopen the SAMPLES table by navigating to Window>New Browser Window and select the table.

4.

Now add the assay values to the SAMPLES table. Choose Discover>Table Utilities>Multiple Column Update. We wish to Update values in and Get values from . Complete the join condition where in the update table matches in the join table. Under Field Under Field Mapping, Mapping, ensure that the , and columns match up accordingly in both tables (This will occur automatically if your columns are setup correctly). Click the OK button. The assay information is added to the SAMPLES table. To make the changes permanent, save the table using the File>Save Table menu.

ASSAYS spreadsheet table can now be closed. The AS


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Update Multiple Columns dialog

Step 2 - Open Remaining Access Tables in MapInfo Professional Step

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5.

Open the COLLARS, SURVEYS and LITHOLOGY tables in MapInfo Professional by choosing File>Open and change Files of type to . (*.mdb)>. Select Select and click Open. Open. Highlight the , and tables, Click OK. OK.

Step 3 - Create Collar Objects Step

B52

6.

From the MapInfo Professional menu bar, choose Table>Create Points. Points. In the dialog box set the table as the Create points for Table. Table . Click on the using Symbol button, and choose a , <8> point font size and OK. OK. Enter for the X-coordinate and for the Y-coord the Y-coordinate inate..

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Discover Tutorials

7.

Click the Projection… button to choose the appropriate AMG Zone. Under Category, Category , choose . Under Category Members choose and click OK. Click OK in the Create Points window. The collars can now be viewed by choosing Window>New Map Window. Window .

Create Points dialog

Note

If you don’t click on the Projection… button, MapInfo Professional uses the default longitude/latitude coordinate system. When viewed in a map window, the points would be stacked upon each other at the north pole (360º, 90º). If this happens, go back to Table>Maintenance>Table Structure and remove the tick in the box Table is Mappable. Mappable . Repeat the procedure outlined above.


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Imported collar and geology tables

Once the collars have been created, open the SURFACE_GEOLOGY table into the same map window. Step 4 - Generate a gridded surface from the collar elevations Step

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8.

A supplementary topographic surface can be used to interpret a crosssection surface topography. topography. If a topographic surface surface is not used, the surface topography is inferred by joining together adjacent collar elevations. If topographic data is not available or as in this exercise collars are closely spaced, Discover can generate the digital elevation model and associated contours.

9.

Choose Discover>Surfaces menu. menu . From the Surfaces menu that is added to the menu bar, choose Surfaces>Create Grid>Interactive…. Grid>Interactive… . Choose as the table to grid and click OK. OK. From the Gridding dialog select as the Fields to grid on the Input tab. From the Grid Geometry tab ensure the Cell Size value is <2>. From the Method tab, select Triangulation as the Gridding Method. Method . On the Output tab save the output grid file as as a Format in the \Discover_Tutorial\Drillholes folder. Click OK and the grid is

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Discover Tutorials

drawn in the collars window. You may need to turn off the visibility of the SURFACE_GEOLOGY layer in order to view the gridded surface.

Gridded surface and collars

Creating Creating Sections B1

Step 5 - Setup Discover Drillhole Project Step

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10.

Select Discover>Drillhole menu. menu. A menu item named Drillholes is added to the MapInfo Professional menu bar, to the right of the Discover menu Discover menu item. Choose Drillholes>Project Manager…. Manager… . Click the New… button and enter a name for the drill project e.g. e.g. . You can then enter a description about the drillhole project in the Description text box. Enter a directory for the drillhole project. Select the folder that contains the data \Discover Tutorial\Drillholes. Set Depth/Length Units to . Select the Project only contains drillholes option.

Note

You can open new tables directly from the Drillhole Project Setup dialog at any time by clicking on the Open Tables… button to bottom left of the dialog.


Defining a Drillhole Project in Discover 11.

When the Next button is clicked, the Drillhole Location dialog appears. Ensure that the columns match the entries required. If not, use the drop down lists to match the appropriate columns. If they are not open, use the Open Tables… button. The sample dataset does not have a negative sign in front of collar dips. Therefore, leave the Down Dip is negative option deselected. Click Next, Next, this will take you to the Downhole Data Tables dialog.

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Drillhole location dialog

12. Use the arrows to move the necessary downhole data tables & from Available to Selected. Check that the Field Mappings align to the correct columns in the downhole data tables. Click Next. Next. 13. The Surfaces dialog will now be open, add the SURFACE GRID you have just created from the collar collar rl from from the drop down Topographic Surface list. Also add the the GEOLOGY> from the drop down list under under Polygon Drape. Drape. Click OK. The Project Manager dialog Manager dialog will appear, note the Project Information on the left hand side and the geology map in the preview window, this allows the user to quickly ascertain exactly what project they are opening. Click Next. Next. 14. The SectionLine dialog will now open. Make sure Create New Section Line Table is selected and click OK.


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Step 6 - Validating your Database Step

B82

15. A dialog will now be displayed prompting you to validate your collar data. Click all the tick boxes and click next. next. Repeat this process for the Survey and Downhole file validations.

16. If any on the validation rules have been broken a report of the errors will be displayed with a show button that opens the table and location of where the validation error has occurred. The table can be opened by clicking the show button. The line of the table that has the error will be displayed and can be changed.

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Data Validation dialog

Step 7 - Produce a Drillhole Plan Step

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15.

Make the collar map window active. Choose Drillholes>Define New Section or Plan.... Plan... . Under the Display Type option on the Define tab, choose Plan. Plan. Enter a Plan Name such as . Click Generate. Generate .


Collar plan drill traces

Alternatively, Alternatively, if you wish wish to create a level plan within within a certain certain elevation range, click on Use elevation range. range . Nominate the central elevation and an envelope width. If you choose a Central Elevation of <35>, with an Envelope height of <10>, only that portion of the hole from 45 to 25 metres elevation is displayed.

Note

To display the downhole data follow the same procedure as outlined for sections in Step 12 .

Step 8 - Select the Collars to include in the Section Step

B03

There are 4 methods for selecting the drill collars to use for a cross-section: 1. Manually enter enter values for the start easting, start start northing, northing, section orientation and section length 2. Select individual collars using the SHIFT key and left mouse button 3. Draw a line on the collar collar map window, window, select the the line and specify an envelope width 4. Preload a previous previous section line file to the drillhole drillhole project project

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Discover Tutorials

16.

For this exercise, use the third method. Make the Cosmetic Layer editable Layer editable in the Enhanced Layer Control window, select the Line tool from the MapInfo Professional Drawing toolbar and draw a horizontal line (left to right) through the middle 3 collars (Holes DDH1, DDH3 and DDH4). Select the line you have just drawn. Choose Drillholes>Define New Section or Plan... and choose Section for the Display Type on the Define tab, Envelope section from the Define Section option and Manual for the Section Envelope. Envelope . Collars which will participate in the section will be displayed in the Select Collars to Display option.

17.

Specify an Envelope width of <10> m and select a View Direction of <0> degrees. To produce a number of east-west sections, click on the Offset Multiple button and tick the Create multiple offsetted sections option. Select two sections, with an Offset towards 0 deg of <-10> m. Select the Annotation tab. Ensure the Collar Label and EOH Label are checked, and that the Label font size is set to <6> for a Map scale 1: <1,000>. Enable Show depth ticks and labels with <25> m depth interval. Click on the Generate button to create the three sections, offset to the south in 10 metre centres. Note that the section envelope is added to the Cosmetic Layer as Layer as a polygon map object.

B13

Step 9 - Section Manager The Section Manager provides Manager provides facilities to open and close existing drill sections, regenerate, display 3D models on section, copy, rename and delete sections, add and delete section layers, and synchronize and preview section lines.


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Section Manager dialog allowing selection and addition/removal of sections

Select Drillholes>Section Manager… and the window displays the available sections and their open/close status, ticked (Open), not ticked (Closed). Step 10 - Extracting Maximum and EOH values Step

B23

From the Drillholes menu it is possible to create a table displaying the Maximum and EOH (End-of-Hole) values from holes within a drillhole project. 18.

Select Drillholes>Calculate Maximum and EOH Values…. Values… . This opens the Drillholes Queries dialog. Choose SAMPLES for the Downhole Data. Data. From the list of fields available, select , and and click OK. OK. Save the Maximum and EOH Values table as in the \Discover Tutorial\Drillholes folder.

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Maximum and EOH Values dialog

Step 11 - Editing Display Colour Patterns for sections Step

B3

Prior to displaying downhole data on a section, you need to create colour patterns relevant to the data ranges. For this example, you will create an individual pattern for lithology and a ranged colour pattern for grade-shading Au text values. 19.

Click on Drillholes>Legend Editor… and click the New button on the Legend Editor dialog. Editor dialog. Check the Populate Legend from dataset box and select from the Dataset pull-down list and from the Field pull-down lists. Select a numeric Data Type and Number of rows as <4>. By default a Legend name of< Samples_Au> is assigned which can be changed manually if desired.


New Legend dialog

When the legend is displayed in the Legend Editor dialog Editor dialog enter the following range details and save:

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Legend Editor dialog

Range 1:

From <0> To <1>, Fg colour

Range 2:


Range 3:


Range 4:


To create the colour pattern for the LITHOLOGY table, repeat the above procedure for a new colour legend and this time select from the Dataset pull-down list and from the Field pull-down list. Select Text as the Data type and name this legend . Click OK. OK. When the legend is displayed in the Legend Editor click Editor click on the Fg (Foreground), Bg (Background) and Patterns cells to select a colour/pattern colour/pattern combination for each unique lithological entry. To quickly select unique patterns, select the Patterns column and click on the Step patterns button. The border line colour, linestyle and thickness can also be modified.


39

B43

Step 12 – Annotate the drillhole cross-sections 20.

Select Drillholes>Display Downhole Data.... Data... . A maximum of 16 downhole variables can be plotted. The sections need to be annotated with rock (trace shade centred on the drill trace), gold (Au) values as text to the right and arsenic (As) values as a line graph to the left of the drill trace. To specify the rock display, click the Trace Shade button. Select the Table and Field . . Default parameters appear in a Trace Shade window. To select your lithology colour look up scheme, click on the Legend drop down menu and chose . Change the other settings so that the trace shade is <2> mm wide at a Map Scale of <1000> with an offset of <0> mm so that it is centred on the drillhole trace. Click OK. OK.

Trace Shade dialog

21.

To define Au text labels click the Text button. From the Text Labels Settings dialog, select Table and Field < Au>. Click on on the Colour by Legend drop down menu and chose colour pattern, and enter a <6> pt font size for a Map Scale <1000>. Set the Position to display <3> mm to the Near Right of the drill trace. Click OK. OK.

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Text Labels dialog

22.

To define an As Linegraph click the Linegraph button. Select Table and Field . Note the As values range between 20 and 3900 ppm. Given the wide data range, you need to set an appropriate scale. Set the Scale to <0.02> for Map for Map Scale of <1000>, this will make the linegraph to be no larger than 78 mm. If you use a higher value, a warning message suggesting that you choose a smaller value is displayed. Set the line colour to red by clicking on the line style colour button colour button and selecting . Position the linegraph linegraph on the left side of the drill trace with an offset of <1> mm and click OK. OK.


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Histogram/Line dialog

23.

Save this current data display setting by clicking the Save button. Save to a setting called . This setting can be used in future to ensure that sections are viewed with a consistent data display.

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Downhole data display definition dialog showing the current display scheme

24.

Select the two vertical sections that have been created in the Sections box and click Apply. Apply. The selected downhole data is drawn on the two sections.


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Step 13 - Producing a Log Display Step

B63

Log displays can be used to display multiple columns of detailed information for individual drillholes in an easy-to-view display. Up to 24 different columns of information can be displayed for a drillhole in a log. This can be particularly useful for examining in detail multi-element migration across a particular lithological boundary. 25.

To produce a log display, return to the drillhole collar location map window. Select 1 drillhole e.g. DDH3. Click on the Log Display button or navigate to the Drillholes>Log Display... menu item.

26.

From the Drillhole Log Display dialog, choose the table from the Select Columns from Data Table list. Chose the column from the Available Columns window, and click the >> button on the Columns to Display in Log dialog.

Columns to Display in Log dialog

27.

Click on the Settings button to choose the log display settings for column. Select the Log Type, Type, with the Colour Pattern, Pattern , and click OK. OK.

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Advanced Column Log Display Settings dialog

28.

Choose the table and , and columns. Click on the Settings button and choose for the log type and the Fill from Trace Shade option to fill the linegraphs with the previously defined lithology log, . Leave the other settings and click OK. OK.

The 4 columns chosen for the log are now listed in the main dialog. You can alter the settings individually for these columns by clicking on the Settings button. You can save this log display setting so that it can be used again later. The Global Settings button allows modification of a number of defaults, including global dimensions, display styles and data handling. Many of these settings can also be changed for individual columns.


29.

Click OK and Discover creates the drillhole log for each of the columns. If you selected multiple drillholes, a log for each drillhole will be created in a separate table.

Downhole log display with lithology fill

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Step 14 - On-Screen Interpretation Step

B73

Geological interpretations of mineralisation or lithological boundaries can be digitized on screen from the sections that have been generated. 30.

Open Section Manager, highlight the section(s) you wish to add geological interpretations to. Click Section Manager>Advanced Button>Add Section Layer . Click OK and accept the default B layer in the New Layer Suffix dialog. Important: The interpretations interpretations must be done on a layer with the B suffix for them to be used in resource calculation tool. Select the B layer in the layer control tool and make it editable. Any type of of object may be digitized. digitized. For this exercise, digitize digitize high-grade high-grade Au ore pods or lithological boundaries. From the Region Style button on the MapInfo Professional Drawing toolbar, choose an appropriate colour. Then with the Polygon button selected, proceed to digitize the interpreted ore zones. After each ore polygon polygon has been been closed, you you need to add the attribute attribute data in the browser window in the column Feature_Code. Feature_Code . Alternatively, use the Information Tool to attribute the data. Additional fields may be added to this table if required. Continue the on-screen interpretation for medium and low grade mineralisation. Remember to use File>Save Table on a regular basis.


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Boundary digitized on section

Once boundaries have been digitized, they may be exported as 3D DXF coordinates for use in another software package. Choose Drillholes>External Data Formats>Export Section Layer as 3D DXF . Step 15 - Generating Sectional Resources Step

B83

The resource calculator uses an inverse distance weighting interpolation to generate a sectional resource for any numerical downhole data. 31.

To create a sectional resource, you need to use 1 of the sections generated above, into which you have digitized some mineralisation boundaries. boundaries. Click on the Drillholes>Sectional Resource Calculator... menu option. Choose one of the available sections and click OK. OK. Select the table in the From table list. Click on in the From column. column . Choose the option to Use Section Layer , and select one of the Feature Code attribute polygons from the Clip to boundary with attributes option. Uncheck the Convert area to tonnes option. Check the option Store Resource in column and select , click OK. OK.

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Discover Drillhole sectional resource calculator dialog

Select OK from the Gridding Section window to accept the grid defaults. The sectional resource will be processed and displayed.


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Discover cross-section with resource calculated grid

Step 16 - Composite Downhole Attribute Data Step

B93

The Discover data compositing feature allows the compositing of downhole attribute data by attribute, cut-off grade, elevation or downhole depth. eg. composite assay data based on lithological unit or at specified intervals down hole. 32.

You can composite by downhole depth by selecting Drillholes>Downhole Compositing.... Compositing... . Select as the Composite using downhole table and navigate to the Elevation tab and the Downhole Depth Depth option. On the left hand side of the dialog select holes and . Select as the Downhole table to composite. composite . Ensure the composite interval is set to <10> m. Click the OK button to start processing.

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Downhole compositing tool dialog

When processing is complete, you can observe the results by opening a new browser window for the table SAMPLES_COMP. This composite data can now be displayed in section just like any other downhole data table, as it can be automatically added to the project by checking the Add output to current project option. You may also wish to experiment with other methods of compositing. Step 17 - Display a Section Grid Step

B04

33.

To add a map grid to the section, make a section window the front map window and select the option Drillholes>Draw Section Grid... or click or click on the Section Grid button. The grid is drawn to fill the current map window view. Alternatively, a section grid can be added automatically automatically using the Add Section to Layout menu option.


34.

51

Choose Drillholes>Draw Section Grid.... Grid... . The X and Elevation spacing can be specified independently of each other. Choose an X-value of <25> metres and elevation of <20> metres. Use the default parameters of grid lines and labels at left and top, and ensure a tick is in the Place labels in mask polygon outside map frame box. Click OK. OK.

If you are not satisfied with the grid position relative to the section, you can move the section and repeat the grid process. The previous section grid is overwritten, unless you change the default table name into which the section grid is created.

Cross-section with grid mask

Step 18 – Formatting and printing a Drillhole Section Step

B14

The following exercise outlines the procedure to print a section to A3 Landscape. 35.

Click on the Section Layout button or navigate to Drillholes>Add Section to Layout.... Layout... .

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Add Section to Layout dialog

36.

In the displayed dialog select the section section to be added added to the the layout layout window. window. Choose <1:500> from the Map Scale pull-down list and from the Frame Setup pull-down list, click OK. OK. A MapSize rectangle is added to the selected section window. Position this rectangle over the section data in the map window. If you wish to change either the map scale or frame size select Re-Specify Parameters from the Section Output menu which has been added to the MapInfo Professional menu bar. When you are happy with the MapSize position select Accept Map Position from the Section Output menu.


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Add Section to Layout dialog

37.

In the second Add Section to Layout dialog, check the Add Plan of Collars to Layout box. This will produce a map with collar positions drawn above the corresponding section and include the surface geology polygons. Click on the Preview button to refresh the map window view. Make sure the section(s) to add to the layout are selected and choose and from the pull-down lists. Click OK. OK. Within the Drillhole Section Grid dialog choose an X-value of <25> metres and elevation of <20> metres. Use the default parameters of grid lines and labels at the left and top, and ensure a tick is in the Place labels in mask polygon outside map frame box. Click OK. OK. The TitleBlock and ScaleBar Options dialog is displayed. Enter in your name as the Author and Author and choose a TitleBlock Position of . Under Other Under Other Options select from the Display List of Layers in map pull-down list. Click OK to display the layout window. A layout window window containing containing the section section will appear. appear. The collar collar plan is automatically added above the section. You can add the XSectLeg to the layout window by drawing a frame object on the layout and specifying this window as its content.

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Section with data display legend printed from the layout window

38.

From the MapInfo Professional File>Page Setup menu option select your printer and a page size of . Save the final layout as a workspace and use the MapInfo Professional File>Print menu option to send the section layout to your printer.

Create Gridded Surface Tutorial

4

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Create Gridded Surface Surfac e Tutorial This tutorial shows how gridded surfaces and contour plans are created and used in Discover. A topographic dataset containing spot heights is used as the data source.

An Exercise in Surface Modelling and Analysis An

B8

The objectives of this tutorial are to interpolate a surface grid and generate a contour plan, create a profile, determine grid slope and aspect, perform sunshading and clip the grid to a region.

Note:



..\\ProgramData\Encom\Discover\Discover_Tutorial (on Windows Vista or 7 operating systems) All references references to the dataset dataset locations locations in the tutorial tutorial exercises exercises ignore ignore the pathing pathing up to \Discover Tutorial.

Discover can create surface grids in many industry standard formats. Discover supplies a number of Grid Handler files which enable to the creation or import grids in any of these formats. Step 1 – Generate a Surface Grid Step

B34

1.

Open the table SPOT HEIGHTS from the \Discover Tutorial \Surfaces folder into MapInfo Professional. From the Discover menu, Discover menu, select Surfaces menu. The Surfaces menu is added to the MapInfo Professional menu bar. Choose Surfaces>Create Grid>Interactive…. Grid>Interactive… . Select the table to be gridded and click OK. OK.

Note

If you select a subset of point to grid, an additional option appears in the dialog list called *Selection*.

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Choose the data to be gridded

The gridding tool consists of a series of tab dialogs for grid parameter set-up that create a surface grid. Accompanying each dialog box is a preview window of the grid as it is created.

The Gridding Tool dialog with a preview of the computed grid of selected data points

2.

On the Input tab of the Interactive Gridding dialog, select from the list of available fields to grid. Located above the grid preview are six buttons and a pull-down list. These buttons control the display properties of the grid in the preview window. Ensure the Histogram equalisation button is selected and from the drop down list.

3.

Right-mouse click in the preview window to display the pop-up menu:


57

Check the Show Value at Cursor to Cursor to see the individual grid cell values displayed. Show Input Points displays the input data points in the preview window. Pseudo Colour button Colour button enables you to toggle between a coloured or greyscale grid. Sun Shading button turns on automatic sun-shading. 4.

On the Method tab, set the Estimation technique to Triangulation. Triangulation . Triangulation uses the Delaunay triangulation method which creates triangles between all data points. Grid cell values are assigned based on the coplanar values of the triangle, where each grid cell is located. This gridding method is best suited to datasets which need to honour the original data input points as accurately as possible: e.g. elevation data. Other types of datasets such as geochemical data can be gridded using different interpolation methods such as Minimum Curvature or Inverse or Inverse Distance Weighting. Weighting. The Grid Geometry tab specifies the grid cell size which may be altered manually if required. The extents of the data to be gridded can also be altered under the Data Coverage options.

5.

On the Output tab save the grid in a called . Click the Save button and Discover will save the grid and open it up into a new map window or the map window containing the SPOT HEIGHTS data.

Statistics button displays the input data statistics, as a histogram distribution and in graphical format. The Statistics Explorer can display the input grid data using univariate, bivariate, spatial and variogram statistical methods.

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Step 2 – Contour Elevation Grid Step

B4

5. Select Surfaces>Grid Contouring.... Contouring... . On the Grid Contouring dialog select as the Grid to contour . Make the minor contour interval 100 and the major 500. Save the output file as the Tutorial\Surfaces default in the Discover Tutorial\Surfaces folder.


59

Specify the contouring, range and output table

Click Process to initiate. When complete click Close on the progress dialog. You can use the Surfaces>Label Contour Lines menu option to add contour labels to your contours. Close the GRID CONTOURS table on completion of this exercise.

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Step 3 - Altering Grid Colours, Sun-Shading and Transparency Step

B54

Once a grid is created or imported it is possible to change the colour scheme applied to the grid. The grid colour will be changed to an elevation colour scheme with real-time sun-shading applied.


7.

61

To alter the grid colour, choose Surfaces>Modify Grid Display.... Display... . On the Colour tab, Colour tab, check the Linear Stretch method and select the colour scheme from the Select Colour Table pull-down list. Click Apply to display the grid with colours ranging from blue (lowest) through brown to white (highest). The Linear Stretch colour method applies the colour pattern linearly between the minimum and maximum grid cell values. Apply the Histogram Equalisation method to see approximately equal numbers of grid cells displayed in each colour. In this same dialog you have the option of applying various forms of grid colouring, such as Linear Stretch Auto Clip, Percentage Breaks, Percentile Breaks, Value Breaks, Multi-banded RGB .

8.

Select the Histogram tab to view the grid cell value colour distribution distribution in histogram format.

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On the Colour tab Colour tab check the Transparency box and move the slider to <20%>, click Apply. Apply. This will enable to view overlying geology data in the next exercise. 9.

Click on the Sun tab. Check the Sun Shade box. Set the Angle to <70> with an Elevation of <60>. Check the Auto Apply box or click on the Apply button to view the changes in the grid window. You can also apply a second light source by checking the Sun Highlight box. This can useful when viewing gridded geophysical data. Alternatively you can click in the Sun tab preview window and drag the Sun Shade or Sun or Sun Highlight sources manually to a new location. Select the Surfaces>Make Legend for Grid... menu option to display a grid legend.

Step 4 - Create a Profile from a Grid Step

B64

10.

Open the GEOLOGY table from the \Discover Tutorial \Surfaces folder. This table contains coloured polygons representing geological units. In the Layer Control window drag the GEOLOGY layer below the TOPO GRID layer. Give the grid a transparency of 50%, to do this go Surfaces>Modify Grid Display on the colour tab, click the Transparency box and drag the slider to 50% you should be able to view the geology polygons beneath the grid. Re-


order the layers so that the GEOLOGY layer is on top of the grid when you have finished.

11.

Make the Cosmetic Layer editable Layer editable from the Layer Control, Control, and with the Line tool selected from the MapInfo Professional Drawing toolbar, draw a line across the centre of the image, from left to right. Select the line in the map window. When a surface profile is created, the surface line is displayed in section view. It is also possible to colour the profile line by draping based on the polygons intersected in the GEOLOGY table.

12.

Click the Surfaces>Draw Grid Profile... button, the new profiler preview window will appear. Click the Options button the Profiler Options dialog will now appear.

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Specifying parameters for profile generation

13.

Check Show Layer Intersections and click the Select Layer button. Layer button. Check and select as the attribute field. Click OK. OK.

Select the Display tab and check the Axis Y, Grid Y, Axis X and Grid X check boxes as below.


14.

Select the DataTable button, the DataTable containing the profile values will appear below the Profile as below.

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Select the Info tab, check Update Position on Mouse Moves. Moves . Move your mouse across the profile and see the values for each sections of the profile appear in the DataTable. DataTable . To save this profile into MapInfo Professional, Professional, click on Export button. Choose a suitable name, it will default to . Click Save, Save, the profile will open in a map window.

The profile data can be seen by opening a new browser window. Complete the exercise by closing the GEOLOGY and PROFILE tables and deleting the cosmetic objects.


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Step 5 - Assign Values from Grid Step

B74

It is possible to assign grid cell values to map objects in a vector layer. This utility can be used to aggregate geochemical data based on geological regions or assign elevation or RL values to drillhole or sample data.

Note

15.

Open the STREAM SAMPLES table from the \Discover Tutorial \Surfaces folder. View the data in browser format and note the blank RL column. To update the browser with RL values extracted from the TOPO GRID select all the stream samples in the map window and choose the Surfaces>Assign Values from Grid… menu option.

16.

Select from the Assign value to column pull-down list and click OK. OK. The RL values are automatically extracted from the grid cell in which each stream sample is located and entered in the browser. Select File>Save Table to save these updates.

When assigning grid cell values to polygon data the mean, minimum or maximum values for all the grid cells that fall within each polygon can be determined.

Step 6 - Grid Queries Step

B84

The Surfaces module contains a powerful grid analysis tool that lets you select portions of the grid that meet specific criteria. Grid cells that meet the specified criteria are saved as polygons in a new layer. The grid cells are selected based on actual grid cell values or by the percentile range of the entire dataset. 17.

Select Surfaces>Grid Query>Select by Multiple Value Ranges… . Select Value and enter the following values into the Levels window: <200>, <400>, <600>, <800>, <1000> and <1200>. Click in the Colour cell Colour cell next to each value and select different colours from the colour palette displayed. Leave the default output file name and location and click OK. OK.

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Grid query parameters for identifying areas by elevation ranges

Experiment with other query parameters. Elevation grid cells can also be selected based on their elevation, slope and aspect properties. Close all tables except for TOPO GRID before proceeding to the next exercise. Step 7 - Using the Grid Calculator Step

B94

The Grid Calculator enables arithmetic operations to be performed on or between one or more grids e.g. add, subtract, multiply or divide each grid cell by a constant value, subtract one grid from another, multiply the values in two grids together to create a third grid, etc. In this exercise we will create a new grid which will represent regolith thickness by subtracting a base of regolith grid from an elevation grid. 18.

Open the SPOT HEIGHTS table from the \Discover Tutorial \Surfaces folder into the current map window. Repeat the previous steps to create a grid using the field. Use the Triangulation method and name the output grid . With the TOPO GRID and BASE_REGOLITH grids both open choose Surfaces>Grid Calculator…. Calculator… . Both grids should be listed in the dialog.

19.

Our expression expression is going to create a new grid called REGOLITH which is the result of subtracting the BASE_REGOLITH grid from the TOPO GRID. Click in the Expression window and type the following:


69

Select the followed by from the grid list and click the Add selected grid button to transfer the grid into the Expression. Expression .

Ensure the following expression syntax is displayed:

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Browse to the \Discover Tutorial \Surfaces folder to save the grid file. Click on the Compute button, new map window will appear with the REGOLITH grid displayed. 20.

The grid can be queried using the Grid Info tool. Click on the Grid Info button located on the Surfaces toolbar, and click on an area of grid that you wish to query. Discover reports the value for the central grid cell selected, as well as the surrounding 8 grid cells. Check the grid cell values in the new grid with the parent grids.


21.

71

Grid cell values can also be viewed using the Surfaces>Grid Utilities>Edit… tool. View the TOPO GRID, BASE_REGOLITH and REGOLITH grid cell values using the scroll bars or clicking in the After preview window with the Select Mode cursor.

Step 8 - Clipping a Grid Step

B05

You may often need to clip a portion of a grid to a polygon boundary. For example, we want to have our TOPO GRID clipped to a tenement boundary. 22.

Open the table TENEMENT BOUNDARY from the \Discover Tutorial \Surfaces folder. Add it to the map window containing the TOPO GRID. Select the TENEMENT BOUNDARY polygon. Navigate to Surfaces>Grid Utilities>Clip…. Utilities>Clip…. Select <* <*Selection*> Selection*> as the table to clip against in the Grid Utility dialog. Make sure the is selected in the grid list. The Clipping region should be Polygonal and the Action should be Clip grid to region. region . The After preview After preview window shows how the resulting clipped grid will appear.

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Note

The grid is clipped to the minimum bounding rectangle of the tenement boundary with areas outside with null values.

23.

Click the Save As button, accept the default saved grid name and save the \Discover Tutorial \Surfaces folder. clipped grid to the \Discover


73

Open a new map window containing the BASE_REGOLITH grid and the TENEMENT BOUNDARY tables. Select the tenement boundary and repeat the clipping exercise to clip the BASE_REGOLITH grid. Step 9 - Volume Calculations Step

B15

24.

Open the TOPO GRID_CLIPPED and BASE_REGOLITH_CLIPPED grids into a map window. To calculate the volume of regolith, choose Surfaces>Grid Utilities>Volume… . Select the grid in the list to display this grid as the Main Grid. Grid. Select from the Secondary Grid pull-down list. The resulting volume is displayed in the Computed volume text box. The value is based on the grid Z scale as well as the map units, in this case, metres, thus the answer is in cubic metres. The Action option allows the selections of differing volume calculation methods. Close all open tables to complete step.

Step 10 - Points to Regions (Voronoi Polygons) Step

B25

A set of Voronoi Voronoi polygons polygons can be be created from point data and mapped mapped thematically. Each data point is used as the centre for a single voronoi polygon with the polygon boundaries spaced at equal distance between the surrounding data points. Voronoi polygons can be used for determining the area of influence for a data point value, e.g. mineral sands grade calculations. 25.

Open the table STREAM SAMPLES from the \Discover Tutorial \Surfaces folder into a new map window. Choose Map>View Entire Layer and Layer and select all points in the table using the Layer Control or alternatively choose Query>Select All from Stream_Samples . From the Surfaces menu, choose Surfaces>Create Voronoi Polygons… . Accept the the default Output Polygon Table name and the default option Clip polygons to convex hull. hull . Click OK. OK. A new layer layer containing containing the polygons polygons is created. created. Each polygon polygon has a Cu, Cu, Pb and Zn field associated with it. Producing a thematic map allows you to visualize the results.

26.

Choose Map>Create Thematic Map…. Map…. Select the Region Ranges Default template. Click Next and ensure that the table and the column are selected. Check Ignore Zeroes or Blanks. Blanks. Click Next. Next. The resulting default ranges are not what is required. To specify the ranges you want, click the Ranges button and choose as the Method. Method. Choose 5 ranges and click the Recalc button prior to clicking OK. OK.

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Creating thematic map ranges for Voronoi Polygons

Click on the Styles button and choose a distinct colour for each of the 5 ranges. Click OK. OK.

Complete the tutorial by closing all tables.

Discover 2012 Tutorials

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