I have two overlapping .ecw layers of the same area, though one is clipped in the middle, with a white edge.
When I set the background value to 255,255,255, and define it as hollow, it only hollows that specific RGB value, when in reality, there are other "white" values in my layer, such as:
254,254,254; 253,253,253.. all the way to 249,249,249.
Is there a way to define the display background value to include more that one unique RGB set of values?
I know I can work around this (clipping, raster calculator, etc.), but I want to retain only one original .ecw file without producing duplicates, therefore I only want to use Arcmap symbology or image rendering tools.
What I need is exactly like the Custom transparency options
in QGIS, but for ArcMap.
Best Answer
Since 10.1, you can use the image analysis tools (Windows > image analysis) to create a mask function that will perform the masking on the fly
Here are the paraphrased instructions on how to implement this, from ESRI's documentation: