Bug report #9793
raster cumulative count cut gives wrong values
| Status: | Closed | ||
|---|---|---|---|
| Priority: | Normal | ||
| Assignee: |  Radim Blazek | ||
| Category: | Rasters | ||
| Affected QGIS version: | master | Regression?: | No |
| Operating System: | Easy fix?: | No | |
| Pull Request or Patch supplied: | No | Resolution: | |
| Crashes QGIS or corrupts data: | No | Copied to github as #: | 18334 |
Description
See the attached raster, it is byte type with just 10 different integer values.
When using qgis to create a color ramp using the CCC (2% and 98%) the
values seems wrong for two reasons:
*) the values presented are 0.996094 and 254.004 : if 0 is the min and
255 is max then that values do not seem that have been cut at 2% on
each side
*) shouldn't the CCC use the raster min/max values, in this case 1 and
10, to compute the cut? otherwise the ramp will be not very useful, in
this case almost all black or white.
History
#1
Updated by Etienne Tourigny about 10 years ago
- File up_5m-int16.tif added
Actually it seems there is a bug specific to Byte data, the min/max are always set to 0.996094 and 254.004 regardless of actual data.
Attaching the same file with Int16 data, and CCC min/max seem ok.
#2
Updated by Etienne Tourigny about 10 years ago
- Status changed from Open to Closed
fixed in master 3e4a915dd239313f71d26d72b72b5d9a160d22f6.
I also added a small fix, by rounding down/up the min/max values to nearest integer. So in this case the min/max are 1 and 9 instead of 1.0 and 8.2.
Plese reopen if it's not ok with you.