In case somebody is still interested in this, I've created a Java command line application which allows you to extract the maps from a Pool of Radiance: Ruins of Myth Drannor installation directly. It is based off the C source code posted here in this thread.
For those curios, my application does fix the swapped red/blue channels of the images (that's why all the images shown here have a blue tint, the red and blue channels are swapped, the images are stored as RGB but the engine seems to use BGR). So the resulting image look like they do in-game. It also allows to stitch together most maps so that you don't have to do it. To run it, you can simply grab the jar from the repository and run that.
For example, if you want to extract a single map-tile (a single MCZ file) you can simply run:
java -jar por-romd-map-extractor.jar "/path/to/por-romd/data/MCZ/twr101.mcz"
And the resulting JPEG will be put into the current working directory. If you want to extract a whole map, for example the overworld map of Myth Drannor, you have to provide the path to the MCZ directory of the PoR:RoMD installation and the map name:
java -jar por-romd-map-extractor.jar "/path/to/por-romd/data/MCZ/" dran
The resulting image is quite large (~23000x11000 pixels), though. Many maps can be extracted like that, for example dran, nr_shrine and so forth. Most dungeons are currently mangled, though, as they do not place their tiles next to each other, but instead have "holes" and reuse some tiles of other maps.
Any comments or suggestions are welcome.
Edited by RobertZenz, 29 January 2024 - 09:39 AM.