Bug report #1380
No Data values are counted as values in the histogram
|Affected QGIS version:||master||Regression?:||No|
|Operating System:||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:||duplicate|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||11440|
After setting a given value as No Data for a raster, the histogram
and min-max statistics are not updated.
Y axis in the histogram is often too high
#3 Updated by ersts - almost 12 years ago
- Status changed from Closed to Feedback
- Resolution deleted (
I have to reopen this. The nodata values were removed from the raster band stats, but they are still showing up in the histogram. It is either something to do with the GDALGetRasterHistogram() or the logic behind which bins to display in QgsRasterLayerProperties::on_pbnHistRefresh_clicked() or a combination of both
#6 Updated by alobo - almost 11 years ago
- Status changed from Feedback to Open
As far as I know this is so because your raster does not define a null
value in the GDAL sense (use GDAL tools to set a null value for that
raster, NOT the QGIS raster properties)
Yes (as extremely delayed feedback to Benoit too) I plan to rewrite
the raster histogramming at some point to not use gdal so that we can
take into account user defined transparency settings etc. I will do
this when I get a few hours to spare!
Hope this helps,
On 01/12/2010 17:14, Agustin Lobo wrote:
Raster histograms include null values, which in many cases severely distorts the
histograms (i.e., images in which a large part of ocean is present or
in which the scene is not a rectangle)
Also, the ability to customize the axes (in particular the x axis) is
#7 Updated by Alister Hood almost 10 years ago
- Pull Request or Patch supplied set to No
Nodata values are also counted when using the "load min/max values from band" feature on the "Style" tab.
This was supposed to be fixed a long time ago: #857-2
I guess I should probably reopen that bug, or file a new one... but it might be the same issue as this with the histogram.
Should this really be "low" priority?
#10 Updated by Giovanni Manghi over 9 years ago
- OS version deleted (
ubuntu 8.04, ubuntu 9.04)
- Crashes QGIS or corrupts data set to No
- Assignee deleted (
- Operating System deleted (
- Affected QGIS version set to master
Probably this is related/duplicate/consequence of #3840
Actually the "no data value" does not make anything NULL, it just turn the pixels transparent, but they retain they original value.