[GRASS-user] 3D raster remove voxels above DEM

[Francois Chartier]

Thanks Moritz

My goal is to summarize the steps for 3d interpolation at the end of the
process. it took me a year to get here and still have a few more steps to
do which i will contact the User list for.
I am actually doing this as part of a 2nd master thesis with le Cnam in
Paris as continuing education, so i will formalize the process.

The voxels above the dem are not Null values in this interpolation as the
vvolrst interpolates the data within the full 'footprint' of the g.region;
is there a possibility to constrain the interpolation to in between the DEM
and lower surface, by setting a more customized Region than a Block?



On Feb 6, 2019 04:45, "Moritz Lennert" <mlennert at club.worldonline.be> wrote:

Hi François,

Thanks for sharing the solution you found. From your first mail it was
clear to me what these voxels above the DEM contained. NULL values ?

It would be great if you could summarize all your experience working on
3D data in GRASS GIS in the wiki, at least by amending
https://grasswiki.osgeo.org/wiki/Help_with_3D with your additions or
corrections ? This would be very helpful many others.

Moritz


On 6/02/19 03:46, Francois Chartier wrote:
> See attached screenshot, I was able to remove voxels above the DEM and
> below bedrock surface using r3.out.vtk and selecting export as
> *pointdata (p)* not voxels.  If exported as a Voxel from r3.out.vtk, the
> voxel file did not open properly in Paraview could be due to size of
> file. I changed option to export as points and it is working.
> grid resolution is 5 x 5 x 1 m over 4km x 4 km x 65 m thickness approx.
> (actual thickness varies between DEM and top of rock).
>
> r3.out.vtk -p -s input=jan27551tens100 at Toronto output=C:\Users\Francois
> Chartier\Documents\GeoModel\WorkingFile\Feb6_VTK_Pts top=GTADEM at Toronto
> bottom=rock at PERMANENT
>
> Le mar. 5 févr. 2019 à 21:20, Francois Chartier <fra.chartier at gmail.com
> <mailto:fra.chartier at gmail.com>> a écrit :

>
>     See attached screenshot, I was able to remove voxels above the DEM
>     and below bedrock surface using r3.out.vtk and selecting export as
>     *pointdata (p)* not voxels.  If exported as a Voxel from r3.out.vtk,

>     the voxel file did not open properly in Paraview could be due to
>     size of file. I changed option to export as points and it is working.
>     grid resolution is 5 x 5 x 1 m over 4km x 4 km x 65 m thickness
>     approx. (actual thickness varies between DEM and top of rock).
>
>     r3.out.vtk -p -s input=jan27551tens100 at Toronto
>     output=C:\Users\Francois
>     Chartier\Documents\GeoModel\WorkingFile\Feb6_VTK_Pts
>     top=GTADEM at Toronto bottom=rock at PERMANENT
>
>
>     Le dim. 3 févr. 2019 à 16:42, Francois Chartier
>     <fra.chartier at gmail.com <mailto:fra.chartier at gmail.com>> a écrit :

>
>         Hi,
>
>         I would like to remove voxels located at a higher elevation
>         than  DEM.
>         I have been trying r3.mapcalc without sucess.
>         Does the XY resolutions of both raster have to the same?
>         any ideas how to do this?
>         Thanks
>         Francois
>
>
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