I have it around somewhere, but the bmp isn't exactly the britania map. it's cut down for dragon and processes none too well. More than likely the file was generated with the map2bmp function in dragon, which I don't really trust.
The best way
I can see going about editing the map depends on how much you want to edit it.
If you're only doing minor work
(like adding a cave entrance or making a road fork to another direction), use WorldForge alone.
If you want to add new islands, create the islands in dragon seperately, you can then use worldforge
(Version 6X) to transfer your newly created map with the island in to the osi map wherever you want.
If you want to edit vast landscapes of already existing osi map use only small sections of the osi_map.bmp, edit them accordingly and just transfer those sections over. and clean up with Worldforge. Or you could use
TSMC.
Hopefully with all three of the above, you should be able to compile a single map, from a few others.
These are just my techniques I've developed on the way of my building history, so there's always others who may help.
