How can I set a surface grid data range to display transparent?


The Surfaces>Modify Grid Display tool allows the transparency of an entire grid to be set.
But how can I set only a particular data range of a grid to be transparent?


To make only a certain data range in a grid transparent, you will have to permanently overwrite these
values with the Null value in the grid.  Any Null values in a grid will not be displayed.

Four methods for accomplishing this are:

1)       Use the Surfaces>Grid Utilities>Replace to replace all a value, with the value NULL.
To specify a range of values, simply use the median value in the range, and use half the total range
value as the tolerance.

For example to omit the range 5-10, replace the value 7.5 with a toelrance of  +/- 2.5, with "NULL".

2)       If you are colouring the grid by data breaks, and wish to apply a minimum cut-off threshold,
use Surfaces>Grid Utilities>Classify to classify each of your ranges to a value, and set the
transparent ranges  to the value NULL.

 3)      Write a simple equation in Surfaces>Grid Calculator, replacing the values if they are in a
range with NULL. Example syntax to remove values in the range of 5-10 is:

output = if (and(InputGrid<=10,
InputGrid>=5), null, InputGrid)

4)       Use Surfaces>Grid Query>Select By Value for values in the range, this will create polygon
bounds to these areas. Then use Surfaces>Grid Utilities>Overlay to replace the area under the
query polygon with NULL, and the background value would be set to the the input grid.


Would you like to...

Print this page Print this page

Email this page Email this page

Post a comment Post a comment

Subscribe me

Remove Highlighting Remove Highlighting

Edit this article

User Opinions (1 vote)

100% thumbs up 0% thumbs down

How would you rate this article?

Thank you for rating this article.

Related Articles

No related articles were found.


No attachments were found.

Last Updated on: 24th of December, 2008