AO users:

I have a set of 1:24000 USGS topo maps for Washington State (tiff format)
that have had the collars clipped so that they can be used in a seamless
mosaic.  I have worked out the code to add these tiles to ArcMap by
hotlinking them to an index layer.  But the tiles are displayed with a solid
color in the border area where the collars have been clipped.  It's simple
to manually change the symbol for this border (value = 255) to "no color" in
ArcMap but I would like to do it programmatically as each tile is added.  I
have tried everything I can think of with rasters, raster layers, raster
bands, raster renderers, etc. but am stymied at this point.

Can anyone point me in the right direction?

Thanks!

********************
David F. Fox, PE
GIS Coordinator

Information Management Office
U.S. Army Corps of Engineers
Seattle District

Phone:  206-764-6083
Fax:  206-764-6816
Email:  david.f.fox@usace.army.mil

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