So this is a pretty basic raster processing question, and perhaps it shouldn't be in the "technical" section of GeoNet, but not sure where else to post it so here goes:
I have a geotiff that that has all of its "background" values available as part of the regular attribute table (they're not "null"). The geotiff is from CropScape (it's a cropland data layer). Via the symbology, I can have the background values not display, but I'd like a more permanent version of having those become the "null" values that they're supposed to be.
When I run it through SetNull it does what I want (convert background values to null values). BUT, it also loses the connection to the colormap (which came with CropScape) that had conveniently been automatically symbolizing the non-background values in the original version.
1) Is there a way to reconnect the colormap to the new version to re-map based on the values? (I just don't want to have to manually enter the 50 different categories of landcover or lead students through a raster join...) I've tried exporting the colormap from the original one and then importing it to the new one, but isn't working.
2) Or, is there a way to run SetNull so that it operates on the value that you'd specified in the conditional statement (in this case, background) but doesn't otherwise lose the colormap link?