[MiWa]

The preprocessed map_c for East Java is 409 MB, when run through the map_c tool it is reduced to less than 20 MB (have to check for the exact figure). I'd estimate that the Italy-Greece-North Africa map contains far more land mass than my East Java map does, in which case the limit could well be my test/development computer rather than the map.

Pure land mass (no rivers or shores) is also compressed easily. This might be the case
for Italy-Greece-North Africa. However, now that you mention it, I'm not sure if the map_c
is decompressed before it is loaded into memory or it is decoded on the fly based
on player's position. The latter would probably cause some performance hits, but
it would allow for far larger in game maps.
Judging by your file sizes, I'm afraid they picked the first option.