If you're making or have made your map in Dragon and are still fixing the zillions of bad water tiles at the coastlines, this might help some.
Certain tiles on the west side coasts always appear to place at 1z too high or low, and leave a thin brown line showing, like so:
This isn't dragon's fault, this is EA/OSI's fault. The water bmp they have in art.mul is actually 1 pixel too high. Copy/download and patch in the following two bmp's, their names is the slot they go into:
www.tragena.net/images/017a9.bmp
www.tragena.net/images/017ab.bmp
After patching them in, your coasts should look like this:
Dragonfire discovered this and fixed it yesterday, he happened to place a normally working water tile on a ground of white marble beside one of the above two tiles, and could tell the height difference.