I was looking for a method to make NoData area transparent, and found this posting https://community.esri.com/thread/198176-nodata-as-black. However, when I tried this method, it still showed some color (see the light grey for the original raster extension). I want to apply transparency to several raster layers' NoData for view analysis. Although there is no value, the view shed result picked up that area as visible part. I am not sure is it because of the color applied?
I hope to use raster for every view category rather than polygon so I can also apply the elevation at the same time.
In the image below, the black spots represent parks, and other areas are NoData. But it still picked up that part as part of layer.