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.
- 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.
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