Preserve colormap when performing an Extract By Mask

Summary

Note:
This article pertains to ArcGIS versions 9.x. Later versions of ArcGIS may contain different functionality, as well as different names and locations for menus, commands and geoprocessing tools.

When performing an Extract By Mask on an image that has a colormap, the colormap is not retained for the new output. The instructions provided show how to retain the colormap colors for the new output.

Procedure

1. Right-click the colormap image > Properties > Symbology tab. Change the symbology to Unique Values. The same colors that were represented by the colormap are now represented by unique values. Click OK.
2. Right-click the colormap image > Save As Layer File.
3. Perform the Extract by Mask on the colormap image.
4. The output raster is grayscale with stretched symbology. Right-click the new Output Raster > Properties > Symbology tab. Select Unique Values and click Import.

5. Browse to and select the layer file created previously. The colors are updated accordingly.