Way back when (at the time that the FR Interactive Atlas was in development), I got a disk of source material scans that I used to make the maps for the FRIA's globe thingy. In that list was a set of black and white work maps showing land mass outlines, tectonics, glaciation, reefs, and so on. The source map I used for those images has major reef areas marked and they sort of filled in space between the islands in Zakhara in the rough outline I did.

The world map at http://thewertzone.blogspot.com/2009...en-realms.html looks to be from the FRIA globe set (done by an artist at TSR). It has pretty much the same configuration as the map I posted above and also has some very odd straight lines in the rightmost continent that were present on the "Areas of Special Interest" map from the source material set.