I'm not sure I can express this very well, so bear with me. Anti-aliasing softens the transition between contrasting pixels, and it allows details smaller than four pixels in area to integrate more successfully into their surroundings. It has the overall effect of reducing the digital look of a raster image, as well as smoothing out very fine details. In this particular image, there are places where the rivers are showing artifacts from being too small. This is a very tiny snippet from your map that illustrates what I'm talking about:
Originally Posted by arsheesh
See how the bevel's highlight is choosing alternating pixels to light up? If the river were bigger, the highlight would be continuous. Anti-aliasing slightly modifies the color of the pixels that the highlight covers only partially, giving the illusion that it and the river are continuous, even though the individual pixels may be neither color.
In fact, there is some anti-aliasing occurring in this image, but the details are so fine that it cannot do much without turning the entire thing into mush.
I like this one better myself. Very nice coastline effect.
@Midgardsormr - thanks for the explanation. I'm not too sure about this, but I think the strong bevel is a result of the emboss and bump map features being applied to the Wilbur height map. It doesn't really bother me that much though.
OK, here is an update. I've got the new climate zones more or less sorted and added a compass and scale. Next up I'll tackle adding the Great Rift in the north-east, and adding some volcanic activity to Mt Nimro and Nimrod.
Forgot to post this earlier. The finished map can be found here.
Thanks for all the helpful comments,