Waterproblem with overlapping photoreal textures

Hi there,

I've got a problem with creating photoreal scenery. I downloaded the scenery from Google Maps with the tool SBuilderX. Due to the fact that the area I want to cover is quite large (about 60*60 km) I could not download the area as one piece with SBuilderX (I always got the error: Could not make Image...) I divided it into little pieces, which are overlapping a bit. This did work quite fine but in FSX the bits which overlap, have an upper layer of watertextures on them.

How can I solve this problem? Is there any tool out there to connect those textures together so that I won't get any areas of overlapping (I already tried to make this with SBuilderX but when trying to load such an 600mb BMP, SBuilderX gives me the error: Wrong file format)??