The Colormap function is a type of raster data renderer. It transforms the pixel values to display the raster data as either a grayscale or an RGB color image based on a color ramp or specific colors in a color map file. You can use a color map to represent analyzed data, such as a classified image or when displaying a topographic map (or an index color-scanned image). The Colormap function is a type of raster data renderer. It transforms the pixel values to display the raster data as either a grayscale or an RGB color image based on a color scheme or specific colors in a color map file. You can use a color map to represent analyzed data, such as a classified image or when displaying a topographic map (or an index color-scanned image).