Hi, I am interested in seeing that TPS interpolation in action. I have been playing a bit with depth data from echo sounders and that kind of data has some special features that make trouble for most interpolation methods that I have been trying. Perhaps the best experience so far is from the “surface” method of GMT https://docs.generic-mapping-tools.org/latest/surface.html.
What makes echo sounder data difficult is that the density of data points is high along the lines ……… (like 1 point per meter) but the survey lines are for example 50-150 meters apart. A wide search radius is smoothing too much along the lines and real details are lost, but a small search radius tends to make big false humps between the lines. I placed some test data into http://latuviitta.org/downloads/depth_data.zip * 14.851.1.001.csv depth data, EPSG:3067 * shapefile about the shoreline * rendered dem * rendered hillshade The DEM is not too bad but it has enough linear artefacts to show the need for improvements. Shoreline is included and it was given for the surface method as a breakline with constant height=0. GRASS has similar method v.surf.rst v.surf.rst - GRASS GIS manual (osgeo.org)<https://grass.osgeo.org/grass78/manuals/v.surf.rst.html>. I have also used a non-open software that gives nice results but I only know that it is using TIN method with some special smoothing. -Jukka Rahkonen- Lähettäjä: Eric <eric.openj...@thefactory.io> Lähetetty: keskiviikko 2. joulukuuta 2020 16.31 Vastaanottaja: jump-pilot-devel@lists.sourceforge.net Aihe: Re: [JPP-Devel] New project/new plugin Congratulations for these great results and these ports Peppe! I really like the colours of your raster interpolations -- they are quite refreshing / juicy :) I don't know if this would be of interest to you but I developed in the past a TPS (Thin Plate Spline) interpolation [1] in order to create contour lines (vector) from a layer of XYZ points/coordinates for example. I even developed a quick OJ plugin to visually test the results but I never released it. If you're interested to add this kind of interpolation, I could release the code in open source somewhere. It should be relatively straightforward to compute an image from it, as once the TPS parameters have been estimated, it's possible to compute any z value for a given (x, y), and therefore to attach this value to your GridExtent / Raster. Just let me know if are interested. Best, Eric On 02/12/2020 13:14, Giuseppe Aruta wrote: Greetings OpenJUMPs I started a new project to create an interpolation plugin for OpenJUMP The plugin takes scattered points loaded in OpenJUMP which have a xyz coordinates and transform them into a raster grid, as Sextante raster. OpenJUMP has already some interpolation plugins via Sextante toolbox (linear regression, Nearest Neighbor, IDW and some Krigings). My plugin tries to extend this capability reusing external codes from other projects which recently are "starving" of development: AdbToolbox, a clone of OpenJUMP, and the good WhiteBox GAT from John Lindsey. Note that, among the others, the TIN interpolation algorithm is my first try to port an imageJ plugin to OpenJUMP with a with unexpected and fast results: it required few modification to port and it is the faster and less memory-eater among the others You can find detail of my project and a link to download the plugin here: https://sourceforge.net/p/opensit/wiki/Interpolation%20Tools/ The plugin uses MultiInputDialog from OpenJUMP which allows to use part of the dialog for user information where you can find info on how to use each algorithm of interpolation. The project is an external plugin as it is still on developing and testing. The day that it will mature enough I plan to port it to OpenJUMP. Best regards Peppe _______________________________________________ Jump-pilot-devel mailing list Jump-pilot-devel@lists.sourceforge.net<mailto:Jump-pilot-devel@lists.sourceforge.net> https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel
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