Hi,
Can Grass GIS create a 3D unstructured grid based on a 3D point data set ?
thanks
F
What do you mean? Like a 3D mesh?
You can use Meshlab, ClouCompare or Paraview to do that, and then exporting it back to GRASS as 3D faces.
C
···
On Sat, Sep 29, 2018 at 5:44 PM, Francois Chartier <fra.chartier@gmail.com> wrote:
Hi,
Can Grass GIS create a 3D unstructured grid based on a 3D point data set ?
thanks
F
grass-user mailing list
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–
Prof. Carlos Henrique Grohmann
Institute of Energy and Environment - Univ. of São Paulo, Brazil
- Digital Terrain Analysis | GIS | Remote Sensing -
http://carlosgrohmann.com
http://orcid.org/0000-0001-5073-5572
Can’t stop the signal.
On Sat, Sep 29, 2018 at 4:45 PM Francois Chartier <fra.chartier@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
Hi,
Sorry to hijack the discussion related to GRASS. But, we are working a new library to handle mesh data. MDAL is currently supported in QGIS. But the idea is to make it generic so other OS GIS application can handle the mesh layer through a generic library similar to GDAL. Here is more info about MDAL:
https://lutraconsulting.github.io/mdal-web/
You can find some example of the formats supported there too.
Regards
Saber
That seems very interesting! Any plans to support PLY?
Carlos
···
On Tue, Oct 2, 2018 at 9:32 AM, Saber Razmjooei <saber.razmjooei@lutraconsulting.co.uk> wrote:
Hi,
Sorry to hijack the discussion related to GRASS. But, we are working a new library to handle mesh data. MDAL is currently supported in QGIS. But the idea is to make it generic so other OS GIS application can handle the mesh layer through a generic library similar to GDAL. Here is more info about MDAL:
https://lutraconsulting.github.io/mdal-web/You can find some example of the formats supported there too.
Regards
SaberOn Tue, 2 Oct 2018 at 03:01, Vaclav Petras <wenzeslaus@gmail.com> wrote:
On Sat, Sep 29, 2018 at 4:45 PM Francois Chartier <fra.chartier@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
grass-user mailing list
grass-user@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/grass-user–
Saber Razmjooei
www.lutraconsulting.co.uk
+44 (0)7568 129733
grass-user mailing list
grass-user@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/grass-user
–
Prof. Carlos Henrique Grohmann
Institute of Energy and Environment - Univ. of São Paulo, Brazil
- Digital Terrain Analysis | GIS | Remote Sensing -
http://carlosgrohmann.com
http://orcid.org/0000-0001-5073-5572
Can’t stop the signal.
The purpose of MDAL is slightly different from 3D meshes such as PLY. In 3D mesh, you store just elevation (either face or corners) and some type of materials. But in MDAL, the aim is to store quantities on top of the mesh (e.g. a mesh for ground elevation and water depth on top over a period of time). So in essence, it is more like 2.5D (+time).
Cheers
Saber
···
On Tue, Oct 2, 2018 at 9:32 AM, Saber Razmjooei <saber.razmjooei@lutraconsulting.co.uk> wrote:
Hi,
Sorry to hijack the discussion related to GRASS. But, we are working a new library to handle mesh data. MDAL is currently supported in QGIS. But the idea is to make it generic so other OS GIS application can handle the mesh layer through a generic library similar to GDAL. Here is more info about MDAL:
https://lutraconsulting.github.io/mdal-web/You can find some example of the formats supported there too.
Regards
SaberOn Tue, 2 Oct 2018 at 03:01, Vaclav Petras <wenzeslaus@gmail.com> wrote:
On Sat, Sep 29, 2018 at 4:45 PM Francois Chartier <fra.chartier@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
grass-user mailing list
grass-user@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/grass-user–
Saber Razmjooei
www.lutraconsulting.co.uk
+44 (0)7568 129733
grass-user mailing list
grass-user@lists.osgeo.org
https://lists.osgeo.org/mailman/listinfo/grass-user
–
Prof. Carlos Henrique Grohmann
Institute of Energy and Environment - Univ. of São Paulo, Brazil
- Digital Terrain Analysis | GIS | Remote Sensing -
http://carlosgrohmann.com
http://orcid.org/0000-0001-5073-5572
Can’t stop the signal.
Saber Razmjooei
www.lutraconsulting.co.uk
+44 (0)7568 129733
Amazing! If you data represents a property (K) that is given for the top elevation (Z) at which it is identified in the database.
With v.vol.rst, are you able to assign that property downwards until the next property value.
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?
Le lun. 1 oct. 2018 à 22:01, Vaclav Petras <wenzeslaus@gmail.com> a écrit :
On Sat, Sep 29, 2018 at 4:45 PM Francois Chartier <fra.chartier@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
On Tue, Oct 2, 2018 at 9:38 PM Francois Chartier <fra.chartier@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@gmail.com> a écrit :
On Sat, Sep 29, 2018 at 4:45 PM Francois Chartier <fra.chartier@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
Hi Vaclav,
Question:
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?
thanks,
Francois
Le jeu. 4 oct. 2018 à 22:48, Vaclav Petras <wenzeslaus@gmail.com> a écrit :
On Tue, Oct 2, 2018 at 9:38 PM Francois Chartier <fra.chartier@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@gmail.com> a écrit :
On Sat, Sep 29, 2018 at 4:45 PM Francois Chartier <fra.chartier@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
Hi Vaclav,
other questions:
how many data points did you use, and
how many grid cells in the 3d grid ?
Le lun. 1 oct. 2018 à 22:01, Vaclav Petras <wenzeslaus@gmail.com> a écrit :
On Sat, Sep 29, 2018 at 4:45 PM Francois Chartier <fra.chartier@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
On Wed, Oct 10, 2018 at 8:34 PM Francois Chartier <fra.chartier@gmail.com> wrote:
Hi Vaclav,
Question:
1-can the value remain constant until the next underlying data point?
v.vol.rst is for interpolation, but a constant value can be achieved with r.to.rast3elev or r.to.rast3, but I think in your case you will likely need some prereprocessing to get the right rasters from your irregular points.
https://grass.osgeo.org/grass74/manuals/r.to.rast3elev.html
https://grass.osgeo.org/grass74/manuals/r.to.rast3.html
I think there was some addon or script for working with soil types (which is how your case sounds). Perhaps somebody knows more about it.
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?
Yes, 3D points (XYZ tuples) and (regular) 3D raster (grid).
if that is the case, how does the value in the raster determined?
v.vol.rst is interpolating the value using “regularized spline with tension” aka RST, i.e. it is applicable to properties which are a real number, but it is not suitable for categorical data.
Is it an interpolated value between the points that fall with in the raster cell footprint?
The interpolation happens for the raster cells (or you can think of them as grid locations in the middle of the raster cell). Usually, there would be much more raster cells than vector points, but the RST interpolation works the same way in all cases.
thanks,
FrancoisLe jeu. 4 oct. 2018 à 22:48, Vaclav Petras <wenzeslaus@gmail.com> a écrit :
On Tue, Oct 2, 2018 at 9:38 PM Francois Chartier <fra.chartier@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@gmail.com> a écrit :
On Sat, Sep 29, 2018 at 4:45 PM Francois Chartier <fra.chartier@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