Bug report #3330

Bug: Glitches in Pretty Breaks graduated rendering

Added by Alister Hood almost 9 years ago. Updated almost 7 years ago.

Status:Closed
Priority:Normal
Assignee:-
Category:Symbology
Affected QGIS version:master Regression?:No
Operating System:All Easy fix?:No
Pull Request or Patch supplied:Yes Resolution:
Crashes QGIS or corrupts data:No Copied to github as #:13390

Description

With some data when using "Pretty Breaks" mode the graduated renderer creates unnecessary categories which are larger than the maximum value in the data. The biggest category still has the maximum value as its upper limit.

e.g. in the screenshot attached where the ZN column is used, the maximum value in the data is 1.58

in the screenshot where the CU column is used, the maximum value in the data is 0.145

Because so many extra columns are created in the CU example the effect on the map is much worse, as all the data ends up in a narrow slice of the colour ramp (all the data is be yellow).

I've joined most of the attribute data to some made up shapes and attached it for an example (a few of the shapes got deleted when using the "join attributes" tool for some reason, but it still has the same problems when using "Pretty Breaks").

pretty_breaks.PNG (24.7 KB) Alister Hood, 2010-12-13 09:04 PM

pretty_breaks1.PNG (41.5 KB) Alister Hood, 2010-12-13 09:05 PM

test_temporal_data.zip (2.91 KB) Alister Hood, 2010-12-13 09:06 PM

fix_pretty_breaks.diff Magnifier (506 Bytes) Alister Hood, 2012-05-29 08:48 PM

Associated revisions

Revision 9d8b9fcb
Added by Giuseppe Sucameli almost 7 years ago

compute the correct number of categories using Pretty Breaks mode (fix #3330)

History

#1 Updated by Alister Hood almost 9 years ago

Sometimes using "Pretty Breaks" mode the graduated renderer creates unnecessary categories which are larger than the maximum value in the data. The biggest category still has the maximum value as its upper limit.

Sorry, that explanation might not be clear enough. See the attached screenshots.

#2 Updated by Giovanni Manghi almost 8 years ago

  • Target version changed from Version 1.7.0 to Version 1.7.4

#3 Updated by Paolo Cavallini over 7 years ago

  • Target version changed from Version 1.7.4 to Version 1.8.0
  • Crashes QGIS or corrupts data set to No
  • Affected QGIS version set to master

#4 Updated by Alister Hood over 7 years ago

  • File fix_pretty_breaks.diffMagnifier added
  • Assignee deleted (nobody -)
  • Pull Request or Patch supplied set to Yes
  • Status info deleted (0)
  • OS version deleted (XP)
  • Operating System changed from Windows to All

This fixes it.

#5 Updated by Alister Hood about 7 years ago

  • Priority changed from Low to Normal

I think I was mistaken assigning "Low" priority.

#6 Updated by Paolo Cavallini about 7 years ago

  • Target version changed from Version 1.8.0 to Version 2.0.0

#7 Updated by Giuseppe Sucameli almost 7 years ago

  • Status changed from Open to Closed

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