Global Mapper v25.0

how to create areas just from selected colors

JSL
JSL Global Mapper UserTrusted User
edited April 2015 in Raster Data
Hi, I'm trying to create areas from a geotiff, but I only want to select some specific colors. The problem is that there two options for creating tifs: 1) without a 256 palette, which only gives me the basic colors to choose from when creating areas from colors, and not all the colors in my image are in that palette; and 2) a 256-color palette, which has a lot more colors than are on my screen, so I have to pick out exactly which colors are on my screen, which is basically impossible.

Is there a way, when using the screen capture function, to have GM create a palette made only out of the colors on the screen at the time?

Thanks for any help.