Hi Joaquim, GMT surface probably has all the features that I need. I followed the tutorial and managed to run surface demos, now I just need to learn how to use my own data as input.
-Jukka- -----Alkuperäinen viesti----- Lähettäjä: Joaquim Manuel Freire Luís <jl...@ualg.pt> Lähetetty: keskiviikko 20. marraskuuta 2019 0.30 Vastaanottaja: Even Rouault <even.roua...@spatialys.com>; gdal-dev@lists.osgeo.org Kopio: Rahkonen Jukka (MML) <jukka.rahko...@maanmittauslaitos.fi> Aihe: RE: [gdal-dev] Gdal_grid and lake bathymetry The GMT surface program has two (well 3) options that are of interest to this. -One, the -Lu<upper> that serves to limit the upper value in the interpolated grid -The other is the option -D that lets you set a soft-breakline (your shorelines). Soft-breaklines are lines whose vertex end up in the grid nodes closest to them. They are called "soft" in contraposition to the hard-breaklines that do not let the interpolation algorithm go across them. Imagine interpolation a terrain with vertical cliffs. Unfortunately that -D option is missing on the html man page but is described on the surface on line help. -Finally, option -M lets you mask the outside lakes region https://docs.generic-mapping-tools.org/latest/surface.html Joaquim -----Original Message----- From: gdal-dev <gdal-dev-boun...@lists.osgeo.org> On Behalf Of Even Rouault Sent: Tuesday, November 19, 2019 10:13 PM To: gdal-dev@lists.osgeo.org Cc: Rahkonen Jukka (MML) <jukka.rahko...@maanmittauslaitos.fi> Subject: Re: [gdal-dev] Gdal_grid and lake bathymetry On mardi 19 novembre 2019 22:03:29 CET Rahkonen Jukka (MML) wrote: > Hi, > > I would like to get some hints about using gdal_grid or some other > utility for lake bathymetry. What I have is typically rather sparse > point data of depths and the shoreline that includes the islands as in > the attached image. The shoreline and all the area that is not lake > basin should have the altitude of zero in the resulting DEM. It means > that interpolation should not overshoot across the shoreline over the dry > land. > > Gdal_grid seems to miss an option for handling the shoreline so I made > a test by converting the vertices of the polygon rings into depth > points. I also filled area around the lake with a gridded points of > zero altitude but the method feels stupid and tedious and the result > was not so fine when it comes to keep the shoreline and land area near it > totally flat. > Postprocessing with gdalwarp -cutline to set to zero non-lake areas ? -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
