I don't know if this is what you mean, but. I gen maps with rwg
kinggen nitrogen and teragon. After generation, and before I enter
the first time, I open the dtm.raw file in photoshop. select the
grayscale layer and copy it to a new image using RGB. 8 bit
if you create 5 copies of the base layer, use the wand and select
20% starting at the darkest color, paint it with the biome color you
like. next do the brightest. proceeding to select other shades in
decending order you save it to the world folder you created and you
have a personal distribution of biomes. just save it as biomes.png.
the actual colors needed are in the biomes.xml near the biome names.
biomemapcolor="#FFFFFF" snow
biomemapcolor="#004000" pine
biomemapcolor="#FFE477" desert
biomemapcolor="#ffa800" waste
biomemapcolor="#ba00ff" burnt
use a solid PEN not brush. Square
check that 1 pixel = actual 1 pixel
to get solid colors and no holes.
before saving temporarily convert it to indexed color, and check table
if it has more than 5 colors adjust, mark down the bogus colors, and revert
back to rgb. use wand set to 0, select the bogus colors and paint them correctly.
or else you may have holes that you fall through the world.
this is manual, but teragon, can do it by selecting values and generating.
So yes, you can actually paint, any biome collage you wish to add to random gen worlds.
If you want to be even more creative, you can use any photo, and repaint it using
just five colors and from birds eye view the biomes will look like the picture.
In regard to the externally generated heightmap. I think the last alpha that allowed it
before converting to the new gen system, was the low A17's. The code was removed from
the dll and the rwgmixer.xml.
That was actually how I first got interested in terraforming.
4Sheetz