[gdal-dev] Unwanted partial transparency when clipping

Michael Corey mcorey at cironline.org
Wed Jul 6 18:58:17 EDT 2011


Hi all:

I'm using a shapefile as a clipping mask to cut out the shoreline from 
some DOQ files that I have merged together. But when I do the clipping 
step, I end up with unwanted semitransparency in the non-clipped areas.

I'm pretty sure the problem is only with my gdalwarp step at the end.

Here's my process:

gdal_merge.py -init "255" -o diablo-combined-center-utm10.tif file file 
file file

gdal_translate -outsize 70% 70% diablo-combined-center-utm10.tif 
diablo-combined-center-utm10-70pct.tif

ogrinfo -al ./diablo_canyon_detail_clipper.shp
//Extent: (XXXX, YYYY) - (XXXX, YYYY)

gdal_translate -projwin XXXX YYYY XXXX YYYY 
diablo-combined-center-utm10-70pct.tif 
diablo-combined-center-utm10-70pct-box.tif

gdalwarp -co COMPRESS=DEFLATE -cutline 
./diablo_canyon_detail_clipper.shp 
diablo-combined-center-utm10-70pct-box.tif 
diablo-combined-center-utm10-70pct-cutout.tif

Can anyone help?

Thanks!

-- 
Michael Corey



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