[GRASS-user] surface interpolation with breaklines

Vincent Bain bain at toraval.fr
Sun Feb 9 04:17:41 PST 2014

Hi Maciej,

Thank you for your reply.
I tested your suggestion but the process was /very/ long (v.trianlge
output was roughly 500 000 triangles). Perhaps a wiser solution would be
to v.to.point (i) contour lines, (ii) breaklines, then merge them in a
single raster an run r.surf.nnbathy.

Finally I found on the web a custom solution based on a nice little
python script named tin2raster, you can find it at the address bellow. I
tried to contact Antonio, the guy who wrote it, but did not get a
reply :


In my case it was very efficient and fast.
Do you think it could represent a potential new option that could be
applied to v.to.rast in order to handle 3d vector areas ?


Le dimanche 09 février 2014 à 12:53 +0100, Maciej Sieczka a écrit :
> W dniu 03.02.2014 18:55, Vincent Bain pisze:
> > Would anyone help me figure out how I could perform this conversion,
> > given that I would rely on a linear interpolation method within
> > triangles faces (the result would be close to what r.surf.nnbathy does,
> > except nor this addon does support breaklines).
> Can you rasterize the output triangle 3d sides, and use that as an input 
> for r.surf.nnbathy?
> r.surf.nnbathy should create a structure similar to v.triangle product, 
> since both use the same Shewchuk's "triangle" algorithm underneath.
> You may try if using only the triangle node vertices alone wouldn't 
> suffice, and extracting those from a 3d vector map should be very easy 
> (v.to.points -n ?).
> Maciek

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