On 15/04/17 05:31, Vaclav Petras wrote: > Back to filling holes in lidar data, I also think that the "fill in the > gaps" approach is quite promising, so I ported the r.fill.gaps module to G7:
Great! I have read the diff and that was very helpful for me. I can see that the old and new raster APIs have only minimal differences. Porting seems very straight-forward. I hope that r.fill.gaps will be useful for others. I did not have LiDAR in mind when I wrote it, but now it seems so obvious that LiDAR processing is an important domain of application for the module. Cheers! Ben > > https://grass.osgeo.org/grass72/manuals/addons/r.fill.gaps.html > > I didn't review the code, but the documentation is very nice and > detailed. I did some mostly formatting updates for the current > submitting guidelines and added complete example with lidar data. > > On Tue, Mar 21, 2017 at 7:29 AM, Benjamin Ducke <bendu...@fastmail.fm > <mailto:bendu...@fastmail.fm>> wrote: > > > I just realized that I have never committed "r.fill.gaps" > to the add-ins repo. > > > Really nice module, please, find more of these in your shelf :-) > > Thanks! > Vaclav > > > > I have just done that now: > > http://grasswiki.osgeo.org/wiki/AddOns/GRASS_6#r.fill.gaps > <http://grasswiki.osgeo.org/wiki/AddOns/GRASS_6#r.fill.gaps> > > Its purpose is filling small gaps in otherwise dense > data using IDW with a pre-computed weights matrix. > It works on rasterized data, so you simply use v.to.rast > on your vector points first. Make sure to set the > cell size small enough so that you don't get many > vector points falling into the same cell. The result > will be an oversampled raster with a lot of small > "no data" cells. That's exactly the intended input for > r.fill.gaps! > > This is not multi-core code, (parallelizing > interpolation algorithms is hard, because you need to > segment the data and then you need to deal with the > seams between the segments), but it is very, very fast, > as long as you keep the IDW radius small. > > The code is optimized to death, which makes it very > hard to read. Another drawback is that it was written > for GRASS 6 (but converting it to GRASS 7 should not > be hard, since it uses only the basic raster API). > > r.fill.gaps is not useful for filling large gaps, both > in terms of performance (for large IDW radii) and > interpolation quality (it's IDW -- enough said). > > > -- Dr. Benjamin Ducke {*} Geospatial Consultant {*} GIS Developer Spatial technology for the masses, not the classes: experience free and open source GIS at http://gvsigce.org _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user