[GRASS-user] 3D unstructured Grid

Francois Chartier fra.chartier at gmail.com
Wed Oct 10 17:34:16 PDT 2018

Hi Vaclav,

1-can the value remain constant until the next underlying data point?
2-by "the output is a regular grid"  does that mean that the points
(vector) can be unstructured, but in the end the raster or mesh is a
regular grid?  if that is the case, how does the value in the raster
determined? Is it an interpolated value between the points that fall with
in the raster cell footprint?


Le jeu. 4 oct. 2018 à 22:48, Vaclav Petras <wenzeslaus at gmail.com> a écrit :

> On Tue, Oct 2, 2018 at 9:38 PM Francois Chartier <fra.chartier at gmail.com>
> wrote:
>> For example, in the example on the webpage, there is a 3D raster for soil
>> moisture; if the soil moisture is measured only for the top of a cylinder
>> along your vertical hole, the next moisture measurement is taken at a lower
>> depth, and the intervals (cylinder length) are not the same along that
>> vertical axis?
> Yes, all are (can be) different. The values are interpolated in between.
> The input are arbitrary places points. The output is a regular grid. Note,
> you may need to explore zscale parameter of v.vol.rst because of the how
> your data looks like.
>> Le lun. 1 oct. 2018 à 22:01, Vaclav Petras <wenzeslaus at gmail.com> a
>> écrit :
>>> On Sat, Sep 29, 2018 at 4:45 PM Francois Chartier <
>>> fra.chartier at gmail.com> wrote:
>>>> Can Grass GIS create a 3D unstructured grid based on a 3D point data
>>>> set ?
>>> All data and visualizations at the following website were created in
>>> GRASS GIS including a 3D regular grid (3D raster in GRASS GIS) interpolated
>>> from a set of 3D points (vector which is 3D, i.e. with z, in GRASS GIS).
>>> Points were soil properties measurement at different depths, 3D raster is
>>> then continuous representation of a selected property.
>>> https://geospatial.ncsu.edu/geoforall/multidim-geovis.html
>>> Module used for interpolation was v.vol.rst:
>>> https://grass.osgeo.org/grass74/manuals/v.vol.rst.html
>>> Vaclav
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