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I am trying to create a 3D bathymetry surface from xyz data.

There is approximately 300,000 points with lat, long and z (depth data). The data is sonar point data similar to LiDAR data.

I want to use GRASS and I'm looking around for the right functions.

I can import the data to grass with v.in.ascii -z and I tried using v.extrude which killed my computer (must be the number of points).

I might be able to create contours in QGIS and use v.to.rast and r.surf.contour but I think I'll lose resolution if it works at all.

I'm not familiar with GRASS and I guess that, this is probably a relatively easy thing to do but I've hit a wall with it. I would imagine someone has encountered this before.

marked as duplicate by Andre Silva, Mapperz Dec 3 '16 at 22:58

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.


Please explain a bit more what you mean with 3D bathymetry surface.. I suppose that you mean the equivalent of a digital elevation model?

You may want to check these two Wiki pages:

  • Hi MarkusN,Yes basically the data is xyz only the z data is negative (below surface). I'm looking at the r.in.xyz function but as yet have had no luck. Thanks for the above suggestions. – user21228 Aug 20 '13 at 14:51
  • r.in.xyz is more a filter based import than interpolation. You can use it to create a raster map from an assemblage of many coordinates using univariate statistics. See here for some related examples: sites.google.com/site/hamishbowman/grassfiles#xyz – markusN Aug 20 '13 at 20:10
  • Thanks for the link markusN. I didn't get r.in.xyz to do the job for me and had to leave it for other work. I'm looking at v.in.ascii and then to rasterise it. I'm having another go today. cheers – user21228 Aug 22 '13 at 10:02

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