Make Part of Raster image transparent

[PhuocDang]

I have a raster image of our facility, but it has unwanted agricultural land and residential neighborhood in the raster image (3 band).  Is there a way I can make my facility more focused by making the unwanted agricultural land and neighborhoods transparent?  Also I have tried to convert my raster image into polygon but it gives me a 999... error message.  I have read some threads saying that it may be due to the 3 band raster image.  how do I convert only 1 band?


Thanks for the help in advance

[JohnSobetzer]

If you have Spatial Analyst you might check out the Combine tool, and convert the combined raster to vectors.  If you only want to work with rasters, and have Spatial Analyst then use a extract my mask.  If you don't have Spatial Analyst or like a different option with rasters, you might also see if you can clip your raster to the desired areas, and then symbolize the No Data areas as no color.  There are several ways to clip, one being using graphics in ArcMap.

[GeospatialTechnology]

This is a bit of a quick and cack handed solution but will give you the results you require.

Drawn a polygon around the faculty. Drawn another polygon larger than your study area. Erase the 1st polygon from the 2nd then you will have a gap where the faculty is. Make this polygon white with no boundary. Play around with the transparency until you get a setting you like.

[PhuocDang]

If you have Spatial Analyst you might check out the Combine tool, and convert the combined raster to vectors.  If you only want to work with rasters, and have Spatial Analyst then use a extract my mask.  If you don't have Spatial Analyst or like a different option with rasters, you might also see if you can clip your raster to the desired areas, and then symbolize the No Data areas as no color.  There are several ways to clip, one being using graphics in ArcMap.

Hi John,

Thanks for the help.  I have tried clipping before, maybe I wasn't doing it correctly, but I will give it another shot.