Hi,
I have a TIN mesh from a simulation model that I want to bring in the GRASS. I was able to bring in the grid nodes in the vector map but am not sure how to create the triangles. I know GRASS has routines for triangulation, but couldn’t find how to to import a already triangulated mesh.
Would appreciate any help with this.
Thanks,
Jitu
Jitendra Kumar wrote:
I have a TIN mesh from a simulation model that I want to
bring in the GRASS. I was able to bring in the grid nodes
in the vector map
excellent.
run 'g.region vect=grid_point_map' then 'g.region -p' and
then 'g.region -a res=...'. Adjust the resolution so that
the rows x columns is about 2000 x 2000 (adjust for your
needs.
Finally use v.surf.rst to make a surface.
This will be a *huge* improvement over a TIN.
but am not sure how to create the triangles. I know GRASS
has routines for triangulation, but couldn't find how to to
import a already triangulated mesh.
Generally GRASS doesn't 'do' TINs because it doesn't need to.
It's raster surface engine has traditionally been its strongest
suit, and TINs grew out of a system with a strong vector engine
but a rather weak raster engine. i.e. they are a quick & dirty
kludge to compensate for lack of a strong raster engine. (ie
being able to efficiently handle massive grids on the fly)
none the less if you really want them have a look in the wiki &
addons, you might find some TIN tools there if you really want
them. see also the v.delaunay module for triangulation code.
Hamish