How to Remove Black nodata areas when Reprojecting

[David.Strauss]

Hello

I have attemted to reproject Gray Scale 8bit TIFF's, from the colected UTM to a 10TM product; using Geo-Express 7

even though I have a tried applying a Transperancy or Background value, the image is squared of with a No-data value...if I set the transperancy of the no data value to 0, the nodata value is black, if I set the transperancy to 255 it is white; Neither are transperant......How do I remove the nodata value? so it is truly transperant

Sincerly Confused...

[rparker]

Hello,

In the MrSID Generation 3 (and older) file format, there is no true no-data value to use. Each pixel value must be in the range of 0-255. So the background value must be made transparent in the viewing application.

JPEG 2000 supports an Alpha band, which provides for the type of no-data transparent value you are looking for. In the near future, MrSID Generation 4 will provide the same Alpha band feature.

For now, try using JPEG 2000 (if your project allows) or setting the background value to be transparent in your viewing application.

[lavalleurb]

Since the "Alpha" feature will work in Gen 4 with both the Background and the Transperancy (no-data) areas, will this allow the better viewing of data in Express Server? Right now if the tiles aren't filled (no-data) completly you have to do some work arounds to make sure you don't have white/black borders on county borders. The look and use of a seamless dataset over an entire state would be very useful.