In Maptek Vulcan there are several data sets that use (and sometimes require) a specific color legend. The Legend Editor module is the tool for creating and editing legends in Vulcan. This tutorial will cover creating a new Colour Legend for a drillhole, assay database.
To begin creating a Colour Legend select the menu option Analyse > Legend Edit > Legend Editor…
Selecting this option will automatically put you in the Legend Editor module and open the Legend Editor Panel. In this panel double click on the ‘[*] New Legend’ entry under the ‘DRILL’ sub folder. This will create a new legend called ‘untitled.’ Click on the untitled legend to select it.
On the right hand side of this panel a number of options will have just become available. Select ‘Numeric’ as the Scheme Type. The numeric legend has more options available than the ‘Alpha’ so you can just leave out the unnecessary steps when creating a name type legend.
Check the box ‘Use Database’ and select your isis database from the dropdown list or browse to it using the ‘Browse…’ button. This step is not strictly necessary but it will allow you to select table and record names from dropdown lists for the rest of this panel rather than typing in names. Anywhere that you have the option to select a field rather than type in a name choose the option to select. This is just one fewer place to make a mistake.
In the ‘Specify Record and Depth fields’ section select your ‘Record(Table)’ from the dropdown (in this case ‘ASSAY’). Also, select the Field Name (AG) and the To field (TO).
In the ‘Use From or Thickness’ section select the From field (as in this example) or Thickness field as appropriate.
Click the ‘Get range’ button to auto populate the Min and Max fields. If your drillhole database uses a negative number as the default for missing or other default data you may need to modify the Min field to be zero. Specify the interval so that you get more than one assay display interval but less than a million :).
Specify a ‘Range Mode’ for displaying the data. The Range Mode will define how to display data that is exactly on the boundary between your display intervals. The default mode is GELT which stands for Greater than or Equal to and Less Than. What this means is that if the assay interval to be displayed is greater than or equal to the lower boundary and is less than the upper boundary then the sample will be labeled with the color for this interval. The other acceptable Range Mode is GTLE (Greater Than and Less than or Equal to). Both of these range modes are acceptable. There are, however, two Range Modes that I think are unacceptable. They are:
- GTLT: Greater Than, Less Than. This would mean that a value exactly on the boundary between assay intervals wouldn't be displayed.
- GELE: Greater than or Equal to, Less than or Equal to. What happens to values exactly between assay intervals is ambiguous. This mode should be avoided.
I don’t know why either of these two Range Methods are included in the Legend Editor. I suppose that Maptek included them just to cover all the possible options no matter how ridiculous.
Next, we want to setup your Colour Ranges. This usually starts with zero and goes up through the max assay value. The button ‘Build Color Ranges’ looks like it will do this for us. Ensure that your interval is not set to zero and press the button.
Type in your From and To values or:
- Hint, when setting the from and to values there is no need to type both values in. These fields work with standard copy and paste operations so you can type in all the from values then copy and paste them one row up and have all but one of the to values.
Finally, we need to assign a color to each assay range. To do this you can click on the color cell to the right of each interval and select a color or you can right click on the header of the column and select Colour Range. Selecting Colour Range will auto fill the colors starting with the colour you select and going sequentially until there are no more intervals that need a colour. This method is quick and easy but not as controllable as assigning individual colours.
Give this legend a name by right clicking on the ‘untitled’ legend in the tree structure on the left. Save your Color Legend by clicking the save icon or selecting File > Save from the menu.
Congratulations. This legend is a required tool for loading drillholes in Envisage. You can now see your data in true 3D.