I just wanted to share what I just found to create/edit overland maps. The process is the same as in the RGB.txt file from Samson, but i found a nice tool to convert to and from RAW files. Just as PSP does, but for free.

Here is the URL

Those won't allow you to edit RAW files, but will convert them. Convert the RAW file, then use your favourite format/editor to work on the map and convert back to RAW.

Two solutions here:
-1- XnView itself, a nice utility for viewing and converting graphic files. Imports about 400 file formats, and exports about 50.
Just make sure you go in Tools/Options/Read/RAW and set width to 1000, Height to 1000 (default overland size in pixels) starting offset to 0, channel order to interleaved and channel type to RGB.
Also, in Tools/Options/Write/RAW, make sure to have Channel order set to interleaved, channel type to RGB and Starting offset to 0.

-2- NConvert. This one is a batch utility to convert files.
You have to make sure you use Samson's settings detailed in the RGB.txt file.

To convert from BMP to RAW
nconvert -out raw -ctype rgb -corder inter -size 1000x1000+0 test.bmp
This line means output format is RAW, channel type is RGB, channel order is interleaved, size is 1000x1000 pixels and header offset is 0. File to be converted is "test.bmp"

To convert from RAW to BMP
nconvert -out bmp -ctype rgb -corder inter -size 1000x1000+0 test.raw


Both tools are free for non-commercial use.
I hope this helps.

Nice find. Definitely very helpful indeed. Looks like it will also handle conversion to png files which is what the C++ code is using to support the graphics.