Feature request #6754

Add logarithmic distribution to raster symbology

Added by Giovanni Manghi almost 5 years ago. Updated 28 days ago.

Status:Open
Priority:Normal
Assignee:-
Category:Rasters
Pull Request or Patch supplied:No Resolution:
Easy fix?:No

Description

see for example here

http://wiki.gis.com/wiki/index.php/Geometric_Interval_Classification

"This classification method is used for visualizing continuous data that is not distributed normally".

The method id already implemented (as "log sitribution") in a QGIS plugin called "1 band color table" available in this repo

http://www.bc-consult.com/free/plugins.xml

logscale.jpg - Examples of logarithmic scales (30.5 KB) Richard Duivenvoorde, 09/19/2017 09:50 AM

History

#1 Updated by Giovanni Manghi 6 months ago

  • Easy fix? set to No

#2 Updated by Richard Duivenvoorde 28 days ago

I was looking for a logarithmic (ten) scale for vector data too...

I think (for vector data) it would need some inputs though, like:
- number of classes
- minimum exponent (optionally based on data minimum)
- maximum exponent (optionally based on data minimum)
- if minimum and maximum should be ranges or just 'bigger then' and 'smaller then' as borders of the ranges

A nice default color ramp to use would be range between HSV colors between 0 and 0.6 (see screendump for examples):
see http://doc.qt.io/qt-4.8/qcolor.html about HSV coloring

But should maybe be a separate feature request :-)

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