[Gdal-dev] terrain model from S-57 nautical chart?

[Thorsten Röllich]

Hello,

I'm building a 3D model of a coastal area in Germany and try to use S-57 datasets as a source.
First I used the program SeeMyDEnc from sevencs to open my datasets and it looked fine. By picking a position on the map, the program shows the primitive DEPARE (Depth Area Group) and the corresponding depth (DRVAL1 and DRVAL2).
This seems to be enough information for modeling a (rough) topography.
So I looked for a converter, that fits my needs... (Something, that converts S-57 to VRML elevation map would be ideal)
What I found was the ogr library and the tools ogrinfo and ogr2ogr.
So I will have to write the converter myself..
The plan was to translate S-57 to GML (which is more human readable) using ogr2ogr and parse all Polygons that describe an Area and the corresponding depth. 
The  translation to GML worked fine, but I could not find any depth information in the file. I tried it with many ogr2ogr options, but the 3rd dimension seems always to be lost.

Does anybody have an idea how to translate the topographic information from S-57 files to an elevation map, or how to extract the polygons and the depth of DEPARE fields?
Very thankful for any hints on this. Kindest regards / Thorsten

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