I've created a hillshade raster (ArcGIS 9.3) and I have 16-Bit tiff image (please see attached).
I need to submit 1 band/8-Bit with grey level (0-255) and set NoData for all pixels outside of the survey limit. My problem is while I'm changing to 8-bits, my NoData pixel changes to 0 value, which is wrong. How can I change this correctly and don't change NoData to 0?
For simple operation I can also use ArcGIS 10, I don't have any extensions for this version.
Best Answer
You can use the Set Null tool in ArcGIS (Spatial Analyst, so use your 9.x version) - see http://resources.arcgis.com/EN/HELP/MAIN/10.1/index.html#//009z00000007000000. If you generate a classified raster where 1 is your study area and 0 isn't, then you can set the corresponding 0 area in your other raster to Null.