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I tried to solve the following issue by myself but without success. On the one hand I have a raster file which is the result of the processing "shapes to grid" tool. On the other hand I have a boundary vector file. Now I wanted to use the zonal statistic tool via processing toolbox. But the result isnt correct. The mean value is not what it should be. The metadata (grid file proberties) shows me the correct mean value. The crazy thing is, when I convert the raster into a shape file again and then converting this shape into a raster file once more the zonal statistics tool works fine.

Could please anyone check this for me? I'm using QGIS 2.2. The files are here (EPSG 25833): Link

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  • I believe that it is a bug of some sort... QGIS 2.4 calculates wrong statistics too. 'Raster' package in R calculates statistics correctly.
    – SS_Rebelious
    Commented Sep 2, 2014 at 11:39
  • Should I open a ticket?
    – Pimpel
    Commented Sep 2, 2014 at 13:34
  • 1
    Yes please open a ticket with the sample data and post a link to the ticket as an answer to this question.
    – underdark
    Commented Sep 2, 2014 at 16:29
  • have you checked the internal pixel size of the analysis. I don't know exactly how the resampling is done with QGIS, but in ArcGIS there is often a downsampling when the extent is large.
    – radouxju
    Commented Jan 29, 2015 at 13:36
  • Here is also some info about incorrect zonal statistics, i dont know if its related. FYI: osgeo-org.1560.x6.nabble.com/…
    – Rutger Kassies
    Commented Jan 29, 2015 at 14:27

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Here is the ticket: Ticket

Is this issue maybe related to this problem (Bug report)?

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