Re: [gdal-dev] Wondering gdal_grid moving average interpolation
On 13.03.2018 09:54, Rutger wrote: It looks alright to me. The moving average algorithm searches (for each pixel) for points within the specified radius, and then averages the values of all those points. "gdal_grid" also supports inverse distance or linear interpolation if you want a more smooth result. It is perhaps surprising that QGIS only exposes a small subset of gdal_grid's capabilities. Yes, you're right, I was just a bit flabbergasted that it looked so bad. There's nothing to make it smooth. The QGIS "bindings" to GDAL are a bit limited, perhaps there hasn't been much interest in expanding them from the initial commits(?). I believe there are also some things that could be thought as bugs - I did a PR(*) a year ago which was not merged (but the issue has been fixed since) - I think a good review of them would be useful. I fixed one issue recently(**) but it is a rather slow process. Ari *) https://github.com/qgis/QGIS/pull/4220 **) https://github.com/qgis/QGIS/pull/6564 ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] Wondering gdal_grid moving average interpolation
It looks alright to me. The moving average algorithm searches (for each pixel) for points within the specified radius, and then averages the values of all those points. "gdal_grid" also supports inverse distance or linear interpolation if you want a more smooth result. It is perhaps surprising that QGIS only exposes a small subset of gdal_grid's capabilities. -- Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
[gdal-dev] Wondering gdal_grid moving average interpolation
I'm translating things on QGIS and now looking at GDAL tool rasterizing point data set with moving average interpolation. That's making a call to gdal_grid with -a average. I've got the attached result from a point set (circles with red border and inside inverse grayscale with interpolated value). The call was gdal_grid -l INPUT -zfield suuntap -a average:radius1=8000.0:radius2=8000.0:angle=0.0:min_points=0:nodata=0.0 -ot Float32 -of GTiff INPUT.shp OUTPUT.tif I'm wondering is that the expected since it looks like the raster cell value is determined by point locations. I would have expected a much more smooth surface without any obvious circular shapes. To me it looks like the computation was not done cell by cell but instead point by point. What am I missing or misunderstanding? Ari ps: This tool is in group 'Raster analysis'. In my opinion it should be in a group 'Point data tools' or something. ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
