Opened 15 years ago
Last modified 13 years ago
#1380 new bug
No Data values are counted as values in the histogram
Reported by: | alobo | Owned by: | timlinux |
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Priority: | major: does not work as expected | Milestone: | Version 1.7.0 |
Component: | Rasters | Version: | Trunk |
Keywords: | Cc: | jdenisgiguere@…, pcav | |
Must Fix for Release: | Yes | Platform: | Linux |
Platform Version: | ubuntu 8.04, ubuntu 9.04 | Awaiting user input: | no |
Description
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
Change History (11)
comment:1 by , 15 years ago
Cc: | added |
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comment:2 by , 15 years ago
Cc: | added |
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Milestone: | Version 1.0.3 → Version 1.2.0 |
Platform Version: | ubuntu 8.04 → ubuntu 8.04, ubuntu 9.04 |
comment:4 by , 14 years ago
Resolution: | fixed |
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Status: | closed → reopened |
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
comment:5 by , 14 years ago
Perhaps related to that: if you build pyramids, the histogram will count all the cells from all levels of pyramids as valid values, thus giving inflated and incorrect results
comment:7 by , 14 years ago
Milestone: | Version 1.2.0 → Version 1.5.0 |
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comment:8 by , 14 years ago
Milestone: | Version 1.5.0 → Version 1.6.0 |
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comment:9 by , 13 years ago
Owner: | changed from | to
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Status: | reopened → new |
Hi Agus,
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!
Regards
Tim
Hope this helps, Benoit
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 just images in which the scene is not a rectangle) Also, the ability to customize the axes (in particular the x axis) is very important
comment:10 by , 13 years ago
Must Fix for Release: | Yes → No |
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comment:11 by , 13 years ago
Must Fix for Release: | No → Yes |
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Seems to me still true on qgis 1.2 from trunk under Ubuntu 9.04