[GRASS-dev] convert 3D polygons or Tins to a DEM?

[Helena Mitasova]

I tested it with the nc_spm data set on an older Mac (~500MB RAM)
and it ran fine with
elev_lid792_randpts (6000 points)
subset of elev_lid792_bepts within the rural_1m region (~45000 points)
and crashed with the full elev_lid792_bepts (319000 points)
with the following message:

GRASS 6.3.cvs (nc_spm_05):~ > v.delaunay -r elev_lid792_bepts  
out=tintest_bebig
v.delaunay(182) malloc: *** vm_allocate(size=8421376) failed (error  
code=3)
v.delaunay(182) malloc: *** error: can't allocate region
.
v.delaunay(182) malloc: *** error: can't allocate region
v.delaunay(182) malloc: *** set a breakpoint in szone_error to debug
node.c:48: failed assertion `n'
Abort trap

It may run with that data set on a bigger machine but it is obvious that
there is a problem with the triangulation as you have suggested.
I am not sure how difficult the fix would be and whether it is worth  
the effort
if it is going to be replaced with something more general,

Helena

On Jan 30, 2008, at 4:07 AM, Maris Nartiss wrote:

> As topology building for large vector datasets works slowly but
> correctly, I would blame delaunay module for generating garbage. I
> interupted v.delaunay run during topology building phase and was able
> to display resulting vector map as lines instead of areas and still it
> made sense only for first 1/3 of map. IMHO it means, that module
> chokes somewhere before requesting to Vect_build_partial
> (vector/v.voronoi/dt_main.c:108).
>
>
> Just my 0.002,
> Maris.
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