7

Is there a way to get similar raster styling in QGIS as ArcGIS does with classified raster data based on percentile scores? In other words, I want an equal number of pixels in one color for my entire raster. I already tried all settings for pseudocolor in QGIS. QGIS 2.12.1 Windows

In ArcGIS this functionality can be found in Layer properties - Symbology - Classified - Classify - Quantile

This is easy with shapefiles but not evident to me with raster files

UPDATE: I started working on a plugin but ran into problems: Quantile in QGIS python Plugin

enter image description here

Dialog window in arcGIS

Equal Interval histogram

Classes in Histogram for equal interval setting

Quantile Histogram

classes in histogram for quantile (Equal number of pixels in class) setting

3
+25

The singleband pseudocolor dialogue has an 'equal interval' option on which you can set the # of classes and the colours themselves:

enter image description here

Is that what you're after?

  • thanks for your comment. I want to set the intervals such that the amount of pixels in each bin is the same. I believe this is a percentile or quantile approach. I cuurently calculate the quantile (5 classes) scores using python and copy them into Qgis but this should be easier. – RutgerH Mar 21 '16 at 20:37
  • I can't see what you're describing in ArcMap... are you able to post a screen shot of what you're after? When I use the same settings dialogue box you're describing, it's doing the same thing the QGIS dialogue is doing above... – DPSSpatial Mar 21 '16 at 20:44
  • 2
    Seems like PostGIS Raster might have a solution, at least for figuring out the breaks: postgis.net/docs/RT_ST_Quantile.html given the result, you could set your symbols manually... but yeah, maybe a feature request for QGIS to have a few more raster symbology methods? – DPSSpatial Mar 21 '16 at 21:20
  • 2
    There's also a GRASS solution: grass.osgeo.org/grass70/manuals/r.quantile.html to at least compute the breaks... – DPSSpatial Mar 21 '16 at 21:20
  • 2
    I haven't seen anything, but I would suggest a feature request for QGIS... seems like a logical addition to the symbol categories... – DPSSpatial Mar 23 '16 at 13:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.