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 have a raster map in QGIS imported from a GRASS mapset with the QGIS GRASS plugin. The problem is that I have null() cells in the GRASS map that appear "colored" in QGIS. How can I set the transparency?

I have tried in 'Proprieties' but it seems that it doesn't work. I would like to know a simple way to solve my problem.

share|improve this question
When I add a GRASS raster into the QGIS map canvas, null cells are transparent. <shrug> – Micha Nov 5 '12 at 7:53
I tested on 3 machines. I can see in the layer's properties window - Transparency tab - the value -2e+09 (MAXINT) is set to 100% transparent. – Micha Nov 5 '12 at 8:01
hi, thanks for the answer. I noticed the layer's properties and I saw that there is a value of -1e+30 Anyway I doubt that the problem is the value. Have you set other things after you imported the grass map? because I still have a colored background instead of null cells transparency. – mattrx86 Nov 5 '12 at 8:39
Can you kindly help me @Micha? – mattrx86 Nov 5 '12 at 20:55
@mattrx86, could you clarify if you see the colored null cells when you first import the raster, or after you have assigned a colormap to it? – dericke Mar 17 '13 at 1:04

This sounds like Bug #4794, which is fixed in trunk and will graduate to the stable release in QGIS 2.0.

share|improve this answer

Your Answer


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.