[gdal-dev] Gdal_grid and lake bathymetry

[Rahkonen Jukka (MML)]

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.

If there are any specialists on bathymetry reading I am eager to learn how to handle my data.

-Jukka Rahkonen-
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