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Colormaps and non supported raster types?

Question asked by J.Tweed on Jul 28, 2020
Latest reply on Aug 2, 2020 by pbecker-esristaff

Downloading GeoTIFF topo maps from: When I open these raster's in ArcMap they have a colormap under the Symbology tab in Properties that I use to make the colored image black and white (not grey scale) for the purpose of a basemap. The site doesn't have a specific 24k quad that I needed, so I downloaded the topo from The National Map Data Download. I was able to find the same year topo that I was looking for (1992) that uses NAD27 GCS but when I open it in ArcMap, there is no colormap option under the Symbology tab (just Vector Field, Stretched, and RGB Composite).


I understand that colormaps are only supported on some 1-band raster types. Wondering if there is a way to convert a raster to a file type that supports colormaps or is there a way to convert from RGB Composite to a colormap? I know I can add 1-band of a 3-band raster which allows more options under the Symbology tab (Vector Field, Unique Values, Classified, Stretched, and Discrete Color), but I am still not able to have the functionality of a colormap. I know there is an Add Colormap tool, but that doesn't work. 


Using ArcGIS Desktop 10.7.1. I have attached low res screenshots of what I start with and what I am trying to end up with. Links to topos below. Any input would be greatly appreciated. Thanks!


Link to GeoTIFF 24k topo that has a colormap and functions as needed

Link to GeoTIFF 24k topo that does not have a colormap that I need to somehow convert