I am using r.patch to combine two raster maps in order to fill in the null values of the other. Is there a way to use r.patch but still maintaining the colortables of the separate raster maps? I do not want to change the colortable of input1 raster map A and input2 raster map B.
It is only possible if the color table of the adjacent raster maps do not overlap. I don't know if r.patch maintains them but you could reassign the colors of the merged color tables after the patching (mosaicking). If there are no identical colors between the maps then the assignment (r.colors) should be successful.