Encom Discover 2012 Tutorial

Encom Discover TM 2012 

TUTORIALS

Table of Contents i 

0BTable of Contents 

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

Conventions in this manual i 

Conventions Used in this Guide 

Certain conventions are used throughout this manual: 

• 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, click 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, click Configuration” 

• References to other sections in the documentation are italicised. For 

example, see Data 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 1 

1B1 

Map Making Tutorial 

The objective of this tutorial is to create a 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 to the dataset locations in the tutorial exercises ignore the pathing 

up to \Discover Tutorial. 

5B 

Professional Quality Map Production 

12BStep 1 - Open Map Layers 

1. 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, tools can be 

opened through the traditional menu interface. 

Note 

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.

2 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. 

Double left mouse click on the ELC title bar to roll the window up to allow 

more workspace when it is not required. 

13BStep 2 –Annotate Linework 

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. 

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.


Select object based on style 

5. To modify the selection to include anticline annotations, navigate to 

Discover>Map Making>Line Annotation, and fill in the following options:


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 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, 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.


14BStep 3 – Add Text Labels 

Adding labels to a map for printing requires a methodical approach to get the 

required 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 open the Label Creator dialog. 

Adding Text Labels dialog 

8. From the Label 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 pts select the 

Map Scale radio button and make Map Scale 1 to . Select the 

Table radio button in output, and accept the default table name and location 

Discover_Tutorial\Map making\Tenements_Labels.tab. Click Generate


15BStep 4 - Creating a Map Legend 

A custom legend can be created using Discover with the layers, columns and order 

of individual legend fully 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. 

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 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 from objects in map 

window 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. Choose point size . 

Repeat the process for Sub-Title Line and choose point size . Click the 

Text Line 1 and Text Line 2 font style buttons and choose point size . 

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), select the 

appropriate option, and click OK.


15. 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, 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.


16BStep 5 - Generating Scaled Hardcopy Output 

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, 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 Scale choose 

(bottom of the scale list) and type into the text 

box. 

Scaled Output Configuration dialog 

19. Under Frame 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 cm. Leave the frame height at cm.


Click the OK button and enter a name to save the setting 

indicating A4 landscape paper, legend and titleblock outside map frame. 

Note 

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). 

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 scale. If you are not satisfied with the scale chosen 

respecify another scale and select Preview again to view the changes. 

When you are satisfied click 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


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: 



Author: 

 

From the Titleblock Position list, choose . The 

default ScaleBar position is Show ScaleBar in 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. 

17BStep 6 – Adding Scaled Legend Frame to Layout 

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.


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 size paper, enter a value of cm for Offset from left. You can always 

adjust the position of the frame once it has been added to the layout. 

18BStep 7 - Creating a Location Map 

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

25. Within the ELC right click and select the option. In the Open 

dialog select the table AUSTRALIA from the \Discover_Tutorial\Map Making 

folder and place it into a new map window (select from the 

Preferred View pull-down list). 

26. Next, create a red rectangle to represent the location of the map within 

Australia. Select the Discover>Object Editing>Key In Shapes menu 

option. 

27. In the Key in Shapes dialog select the from the Draw 

onto pull-down list.


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 pixels. XY Units are 

in decimal degrees. 

Click the Enter Coordinates button. Enter XY coordinate pairs as follows: 

Corner 1 Xm: 

Corner 1 Ym: 

Corner 2 Xm: 

Corner 2 Ym: 

Click OK and Close. 

28. Choose Map>Save Cosmetic Objects to save the newly created rectangle 

to a table called in the folder \Discover_Tutorial\Map Making. 

View the entire layer for AUSTRALIA using the zoom tool for the AUSTRALIA 

layer in the ELC dialog. 

19BStep 8 - Adding the Location Map to the Layout Window 

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: 

Frame width (cm): 

Frame height (cm): 

Offset from left (x cm): 

Offset from top(y cm): 

Position in Map Centre 

Easting: 

Northing: 

The location map is added to the layout window.


20B 

Step 9 - Exit Scaled Output and Plot Map 

30. Select Scaled Output>Exit Scaled Output 

A dialog box appears allowing you to save the map grid, titleblock, 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 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. 

31. Print the displayed scaled map by choosing 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 15 

2B2 

Register 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 Image tool is a powerful utility that enables the 

registration of raster images in geographic real-world coordinates. Unlike image 

registration using MapInfo Professional, the 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: 





systems) 



6B 

Geo-register Image 

21BStep 1 - Open Rectify Image Dialog 

1. 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, tools can be 

opened through the traditional menu interface. 

Note 

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 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.


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 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.


2BStep 2 - Register the Image 

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.


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 into the Map_X cell and 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.


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 

the _ImageControlPoints layer editable in the map window, drag the control 

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 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 _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.


Discover contains a number of additional tools for working with images. These can 

all be found on the Images menu and include the following: 

• 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 contrast and brightness and modify colour and gamma Red, 

Green, Blue channels. 

• Filter Image 

Apply smoothing and edge detection filters 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 utility is compatible with BMP, JPG, PNG, GIF and TIFF 

raster image formats only. 

See Discover Reference Manual or Help for detailed information on each menu 

option.

Drillhole Display Tutorial 23 

3B3 

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. 

7BDisplay and Output Drillhole Sections 

9BData Sources 

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. 

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, 

ASSAYS.XLS and SURFACE_GEOLOGY.TAB. 

Note: 





systems) 



10B 

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 

• Create objects for the collar locations 

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


23BStep 1 - Merge Sample Data and Assay Data 

1. Open the Excel spreadsheet of assay data in MapInfo Professional by 

choosing File>Open and changing Files of type to , 

select file. 

Note: 

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. The dialog should now display the worksheet range 

. Click OK. A browser window opens displaying the 

columns SampNo, Au, 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. Select the 

table and click OK. A browser window appears displaying the columns 

HoleID, From, To and 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. 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 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. 

The ASSAYS spreadsheet table can now be closed.


Update Multiple Columns dialog 

24BStep 2 - Open Remaining Access Tables in MapInfo Professional 

5. Open the COLLARS, SURVEYS and LITHOLOGY tables in MapInfo 

Professional by choosing File>Open and change Files of type to . Select and click Open. 

Highlight the , and tables, Click 

OK. 

25BStep 3 - Create Collar Objects 

6. From the MapInfo Professional menu bar, choose Table>Create Points. In 

the dialog box set the table as the Create points for Table. 

Click on the using Symbol button, and choose a , 

point font size and OK. Enter for the X-coordinate and 

for the Y-coordinate.


7. Click the Projection… button to choose the appropriate AMG Zone. Under 

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. 

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. Repeat the procedure outlined above.


Imported collar and geology tables 

Once the collars have been created, open the SURFACE_GEOLOGY table into the 

same map window. 

26BStep 4 - Generate a gridded surface from the collar elevations 

8. A supplementary topographic surface can be used to interpret a crosssection 

surface topography. If a topographic 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. From the Surfaces menu that is added 

to the menu bar, choose Surfaces>Create Grid>Interactive…. 

Choose as the table to grid and click 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 . From the 

Method tab, select Triangulation as the Gridding 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


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 

1BCreating Sections 

27BStep 5 - Setup Discover Drillhole Project 

10. Select Discover>Drillhole menu. A menu item named Drillholes is added 

to the MapInfo Professional menu bar, to the right of the Discover menu 

item. 

Choose Drillholes>Project Manager…. Click the New… button and enter a 

name for the drill project 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, this will take you to the Downhole Data Tables dialog.


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. 

13. The Surfaces dialog will now be open, add the SURFACE GRID you have 

just created from the collar rl from the drop down Topographic Surface list. 

Also add the from the drop down list under 

Polygon Drape. Click OK. The Project 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. 

14. The SectionLine dialog will now open. Make sure Create New Section Line 

Table is selected and click OK.


28BStep 6 - Validating your Database 

15. A dialog will now be displayed prompting you to validate your collar data. 

Click all the tick boxes and click 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.


Data Validation dialog 

29BStep 7 - Produce a Drillhole Plan 

15. Make the collar map window active. Choose Drillholes>Define New 

Section or Plan.... Under the Display Type option on the Define tab, 

choose Plan. Enter a Plan Name such as . Click Generate.


Collar plan drill traces 

Note 

Alternatively, if you wish to create a level plan within a certain elevation range, 

click on Use elevation range. Nominate the central elevation and an envelope 

width. If you choose a Central Elevation of , with an Envelope height of 

, only that portion of the hole from 45 to 25 metres elevation is displayed. 

To display the downhole data follow the same procedure as outlined for sections 

in Step 12. 

30BStep 8 - Select the Collars to include in the Section 

There are 4 methods for selecting the drill collars to use for a cross-section: 

1. Manually enter values for the start easting, start 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 map window, select the line and specify an 

envelope width 

4. Preload a previous section line file to the drillhole project

31B 


16. For this exercise, use the third method. Make the Cosmetic 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. Collars which will participate in the section will be 

displayed in the Select Collars to Display option. 

17. Specify an Envelope width of m and select a View Direction of 

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 m. 

Select the Annotation tab. Ensure the Collar Label and EOH Label are 

checked, and that the Label font size is set to for a Map scale 1: 

. Enable Show depth ticks and labels with 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 a polygon map object. 

Step 9 - Section Manager 

The Section 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.


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). 

32BStep 10 - Extracting Maximum and EOH values 

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…. This opens the 

Drillholes Queries dialog. Choose SAMPLES for the Downhole Data. 

From the list of fields available, select , and and click OK. 

Save the Maximum and EOH Values table as in 

the \Discover Tutorial\Drillholes folder.


Maximum and EOH Values dialog 

3BStep 11 - Editing Display Colour Patterns for sections 

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. 

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 . 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 enter the 

following range details and save:


Legend Editor dialog 

Range 1: 

Range 2: 

Range 3: 

Range 4: 

From To , Fg colour 




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. 

When the legend is displayed in the Legend Editor click on 

the Fg (Foreground), Bg (Background) and Patterns cells to select a 

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.

34B 


Step 12 – Annotate the drillhole cross-sections 

20. Select Drillholes>Display Downhole 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 mm wide at a Map Scale of with an offset of mm so that 

it is centred on the drillhole trace. Click OK. 

Trace Shade dialog 

21. To define Au text labels click the Text button. From the Text Labels 

Settings dialog, select Table and Field . Click on the 

Colour by Legend drop down menu and chose colour 

pattern, and enter a pt font size for a Map Scale . Set the 

Position to display mm to the Near Right of the drill trace. Click OK.


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 for Map Scale of , 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 and selecting 

. Position the linegraph on the left side of the drill trace with an offset of 

mm and click OK.


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.


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. The selected downhole data is drawn on the two sections.


36BStep 13 - Producing a Log Display 

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, with the 

Colour Pattern, and click OK.


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. 

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


37BStep 14 - On-Screen Interpretation 

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 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 object may be digitized. For this exercise, digitize 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 has been closed, you need to add the attribute data 

in the browser window in the column 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.


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. 

38BStep 15 - Generating Sectional Resources 

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. Click 

on the Drillholes>Sectional Resource Calculator... menu option. 

Choose one of the available sections and click OK. Select the 

table in the From table list. Click on in the From 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.


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.


Discover cross-section with resource calculated grid 

39BStep 16 - Composite Downhole Attribute Data 

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.... Select as the Composite using downhole 

table and navigate to the Elevation tab and the Downhole Depth option. 

On the left hand side of the dialog select holes and . 

Select as the Downhole table to composite. Ensure the 

composite interval is set to m. Click the OK button to start processing.


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. 

40BStep 17 - Display a Section Grid 

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 on 

the Section Grid button. The grid is drawn to fill the current map window 

view. Alternatively, a section grid can be added automatically using the 

Add Section to Layout menu option.


34. Choose Drillholes>Draw Section Grid.... The X and Elevation spacing can 

be specified independently of each other. Choose an X-value of 

metres and elevation of 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. 

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 

41BStep 18 – Formatting and printing a Drillhole Section 

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....


Add Section to Layout dialog 

36. In the displayed dialog select the section to be added to the layout window. 

Choose from the Map Scale pull-down list and 

from the Frame Setup pull-down list, click 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.


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. Within the Drillhole 

Section Grid dialog choose an X-value of metres and elevation of 

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. 

The TitleBlock and ScaleBar Options dialog is displayed. Enter in your 

name as the Author and choose a TitleBlock Position of . 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 containing the section will appear. The 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.


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 55 

4B4 

Create Gridded Surface 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. 

8BAn Exercise in Surface Modelling and Analysis 

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: 





systems) 



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. 

43BStep 1 – Generate a Surface Grid 

1. Open the table SPOT HEIGHTS from the \Discover Tutorial \Surfaces folder into 

MapInfo Professional. From the Discover menu, select Surfaces menu. The 

Surfaces menu is added to the MapInfo Professional menu bar. 

Choose Surfaces>Create Grid>Interactive…. Select the 

table to be gridded and click OK. 

Note 

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

called *Selection*.


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:


Check the Show Value at Cursor to see the individual grid cell values 

displayed. 

Show Input Points displays the input data points in the preview window. 

Pseudo 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 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 

Distance 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.


4BStep 2 – Contour Elevation Grid 

5. Select Surfaces>Grid 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 

default in the Discover Tutorial\Surfaces 

folder.


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.


45BStep 3 - Altering Grid Colours, Sun-Shading and Transparency 

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. To alter the grid colour, choose Surfaces>Modify Grid Display.... On the 

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 in 

histogram format.


On the Colour tab check the Transparency box and move the slider to 

, click 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 

with an Elevation of . 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 Highlight 

sources manually to a new location. 

Select the Surfaces>Make Legend for Grid... menu option to display a grid 

legend. 

46BStep 4 - Create a Profile from a Grid 

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 from the Layer 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.


Specifying parameters for profile generation 

13. Check Show Layer Intersections and click the Select Layer button. Check 

and select as the attribute field. Click 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.


Select the Info tab, check Update Position on Mouse Moves. Move your 

mouse across the profile and see the values for each sections of the profile 

appear in the DataTable. 

To save this profile into MapInfo Professional, click on Export button. 

Choose a suitable name, it will default to . Click 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.


47BStep 5 - Assign Values from Grid 

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. 

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. 

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. 

Note 

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. 

48BStep 6 - Grid Queries 

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: , , 

, , and . Click in the 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.


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. 

49BStep 7 - Using the Grid Calculator 

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…. Both grids should be listed in the dialog. 

19. Our 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:


 

Select the followed by from the grid list and 

click the Add selected grid button to transfer the grid into the Expression. 

Ensure the following expression syntax is displayed: 


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. 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. 

50BStep 8 - Clipping a Grid 

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…. Select 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. The After preview window shows 

how the resulting clipped grid will appear.


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 

clipped grid to the \Discover Tutorial \Surfaces folder.


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. 

51BStep 9 - Volume Calculations 

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. 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. 

52BStep 10 - Points to Regions (Voronoi Polygons) 

A set of Voronoi polygons can be created from point data and 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 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 default Output Polygon Table name and the default option Clip 

polygons to convex hull. Click OK. 

A new layer containing the polygons is created. Each polygon has a Cu, Pb 

and Zn field associated with it. Producing a thematic map allows you to 

visualize the results. 

26. Choose Map>Create Thematic Map…. Select the Region Ranges Default 

template. Click Next and ensure that the table and the column are selected. Check Ignore Zeroes or 

Blanks. Click 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. Choose 5 ranges and click the Recalc button prior to clicking OK.


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. 

Complete the tutorial by closing all tables.

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