Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm trying to convert a bmp image in BNG to WGS84 using gdalwarp (via QGIS). It seems to be running without errors but the output is all black. What am I doing wrong?

share|improve this question
up vote 2 down vote accepted

Did you try it outside of QGIS (e.g. via command line?) - that would be the first thing to test.

share|improve this answer
1  
specfically I used the verison of gdal that FWTools provides to get it to work – jk. Feb 20 '11 at 7:21

When I was doing some cropping of geotiff images with gdalwarp, my mask was making the area that I wanted dropped all black. A co-worker advised that the direction of the coordinates could be the issue. Apparently drawing coordinates in one direction (Clockwise for example) will keep everything outside the crop area and the other way (counter clockwise) will keep everything inside of the drop area. When I changed the direction of my cutline coordinates, it did what was expected. Hope this helps.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.