Thanks Ben, I will give that a try. I am finding that the Interpolation algorithm is taking forever on a small data set.
Doesn't the Postgres PDAL extension handle point data like this? Would there be a benefit of putting the data in PostGIS? Thanks, Calvin On Fri, Apr 20, 2018 at 1:10 PM, Benjamin Ducke <[email protected]> wrote: > Hi Calvin, > > On 20/04/18 18:46, Richard McDonnell wrote: > > Calvin, > > > > Under Processing Toolbox, Type interpolation into the search bar, the > > tool you want can be found there. > > None of the typical GIS interpolation tools will be > of much help here, since they have all been optimized > to work with relatively sparse data. They will be > too inefficient for high-resolution geomagnetic data. > > You data is already dense, with some gaps. So you need > something that is fast and efficient for small > interpolation radii, and will not produce too many > artefacts. > > If you can use the GRASS7 plug-in from within QGIS, > than this is a good processing path: > > 1. Rasterize your data points, using a cell size > small enough so that you don't have too much information > loss (i.e. not too many occurrences of more than one data > point per cell). This might take a little trial and error > to find good settings. You should end up with a raster > where you have gaps of max. 1-3 empty cells between cells > with measurement data. > > Now you need to fill these relatively small gaps. > > 2. Use r.fill.stats from current GRASS 7.4: > > https://grass.osgeo.org/grass74/manuals/r.fill.stats.html > > ... because that has been designed exactly for the > purpose. Set the interpolation radius as small as > possible, so that it just manages to fill the gaps. > With a small radius, r.fill.stats is very fast and > memory efficient, even on very large raster datasets. > > Note that r.fill.stats is part of GRASS 7 only since > version 7.4. If your QGIS ships with an earlier > version, then you might have to update your GRASS 7 > binaries manually. > > Best, > > Ben > > > Regards, > > > > Richard. > > > > On 20/04/2018 16:42, C Hamilton wrote: > >> I don't know how many of you have worked with archaeological > >> magnetormetry data, but I have been asked to help with magnetometry > >> data of the ancient Mound Builders in North America. I am looking for > >> some suggestion on how to best turn the irregular magnetic data points > >> into an image. > >> > >> I see an Interpolation plugin that perhaps is the solution, but I also > >> see that it is not part of QGIS 3. Is this because it has not been > >> ported yet, or is not going to be porter, or is there a better solution? > >> > >> I don't know if any of the Lidar tools would work for this or not. > >> LASTools is a commercial product and the locked version only works > >> with small data sets and adds noise unless you purchase a license. At > >> least that is how it was the last time I used it. > >> > >> Thanks for any suggestions. > >> > >> Calvin > >> > >> > >> _______________________________________________ > >> Qgis-user mailing list > >> [email protected] > >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > > > > -- > > *_Richard McDonnell_* > > *GIS Specialist PgD GIS AssocSCSI* > > *OPW FRM Data Management* > > *52 Stephens Green, Dublin 2.* > > TEL: 01 6476543 > > > > <http://www.opw.ie/> > > > > > > > > Email Disclaimer: http://www.opw.ie/en/disclaimer/ > > > > > > _______________________________________________ > > Qgis-user mailing list > > [email protected] > > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > > > > > > -- > Dr. Benjamin Ducke > Deutsches Archäologisches Institut (DAI) > Zentrale Berlin, IT-Referat > * Projekt "Stunde Null" * > _______________________________________________ > Qgis-user mailing list > [email protected] > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >
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