Object-based color is constructed by assembling polygonal shapes, each of which is filled with a uniform color. The boundaries between polygons can be emphasized with lines, or not. Both OrbMapAI and FiniteMap can produce color maps of this type, using a 12-color palette which is defined in their respective frame .ai files.
Compared to high-contrast black & white maps, these give a much quicker and more pleasant visual impression of the quantity which has been contoured (unless the reader is color-blind!).
Compared to bitmap-based color maps, they are less appealing due to the limited range of colors available. However, they have an advantage of compressing very nicely into small .GIF files. Each of the examples below is under 26 KB as a .GIF, although the original .ai file was 1.9 MB.
Example with contour lines emphasized in black:
Example without the overlay of contour lines:
