I'm currently aggregating multiple viewshed rasters keeping only the maximum value from each cell. When using r.series like shown below, the produced result is incorrect with added no data values. Why?

How I set up r.series: enter image description here

The 7 different rasters I'm aggregating looks like this: raster0 raster1 raster2 raster3 raster4 raster5 raster6

And the aggregated results looks like this: Aggregated_maximum

And as you can see above, the aggregated raster is definitely not aggregating maximum values, and on top of that adding no data values.

Is this a bug in r.series or is there something wrong with my data? I've also tried SAGA GIS Mosaic function which provides a more accurate result, but since some sort of nearest neighbor interpolation takes place, the results isn't 100% correct but much better then r.series: SAGA-GIS

Can anyone provide a work-around or point out what's wrong? Smaller clip of the data I'm using, style included. If anyone wants to try and reproduce the error?

  • I can't replicate your problem from QGIS or GRASS, seems correct looking at the values. – Anna Sep 27 '17 at 20:08
  • Thanks for trying Anna! So strange, if there's nothing wrong with the data - what could be causing the error for me? r.series maximum worked perfect two days ago. Do you happen to know a work-around in raster calc? – johlund Sep 27 '17 at 22:43
  • I've spent too many hours eliminating error sources to live with the 95 % correct interpolated Saga-gis mosaic results. Shouldn't be impossible to aggregate seven layers with the same extent, keeping only the maximum value of each cell!? – johlund Sep 27 '17 at 22:51
  • I can't replicate the problem on my Mac running QGIS either, the results are correct there. I even tried to reinstall QGIS completely on this Windows machine I'm using right now, but no luck. Still the same results with errors and no data values. – johlund Sep 28 '17 at 10:33

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