[GRASS-user] 3D Geometry and multiple import

[Hans-Jörg Keiler]

aswin indraprastha schrieb:
> Sorry if my question is not quite clear.
> I want to build an campus area in GrassGIS. My primary 3Dmodelling is Sketchup.
> Since there is no detailed geo-referenced map in my case, I begin to
> develop base map by rectifying scanned map from existing vector map.
> It was campus site plan. So now, I have vector map of campus plan  in
> Grass GIS.
> How do I assign each building so that if I import into Grass, they fit
> exactly to their position in vector map (site plan)?Of course,
> SketchUp does not have coordinate system.
> It is important for me because I want to build attribute on each
> building using Postgresql connectivity (spatial database).
> I have not try v.transform yet.
> I had looked your NY map, how you import different 3D shape of
> building into Grass?
>
> Thank you again for your kind support.
> _______________________________________________
> grass-user mailing list
> grass-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/grass-user
>
>   
Hi,

I also tried to import some Sketchup data into GRASS. I know it is a 
mass that those dxf-files contain no xy-values ;-). Unfortunately, the 
only software I know solving this problem is ArcGIS, they have a 
sketchup-plugin for export and in Sketchup you can export your model as 
Esri-multipatch. This way, the data would not loose the xy-values and 
database connection (and it would contain texture-information), so each 
building on your campus area would fit on its place.

So the solution I know was posted to the mailing-list a few weeks ago:
- get 2D building polygons with heights as attribute column (v.in.ogr)
- get DEM (r.in.gdal)
- get orthophoto (r.in.gdal)
- interpolate dem to highres (I used 2m pixels) with r.surf.rst
- extrude 2D buildings to 3D (v.extrude, give building heights attribute
 column as option and 2m DEM as elevation)
- start nviz with  nviz dem2m vect=buildings3d col=orthophoto

I'm pretty knew to GRASS, so I'm sorry I can't help you much. I thought 
about trying with OssimPlanet, but as I learned Ossim requires 
gdal1.3.2, which means to deinstall gdal1.4, required for GRASS.... No 
way! ;-)

So I also think the only way handling this sketchup-data is to 
georeference each building / group of buildings, like it was already said.
Maybe there are any developement plans aiming in that direction (e.g. a 
sketchup or another 3D-modelling program plugin)?

Regards,

Hajo










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