Dear list,
I have a 2D polygon file containing building data which is associated with height values (within attribute table). Is it possible to create a 3D-vector/raster file from that file. And how to do it? Hence I would like to drape it over a DEM both in 3D!
Any suggestions?
Regards
Christian
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On Mon, Sep 15, 2008 at 10:38 AM, christian Brandt
<chrisbrandt74@hotmail.com> wrote:
Dear list,
I have a 2D polygon file containing building data which is associated with
height values (within attribute table). Is it possible to create a
3D-vector/raster file from that file. And how to do it? Hence I would like
to drape it over a DEM both in 3D!Any suggestions?
Sure (example for North Carolina data set):
Note: v.extrude requires polygons as input to extrude to 3D house blocks:
v.extract P079215 out=bldg_resid where="layer='BLDG_RESID_BL'"
v.extract P079215 out=bldg_cmcl where="layer='BLDG_COMMER_BL'"
# convert lines to boundaries (may not be needed in your case)
# add centroids (may not be needed in your case):
v.type bldg_resid out=bldg_resid_bnd type=line,boundary
v.centroids bldg_resid_bnd out=bldg_resid_pol
v.type bldg_cmcl out=bldg_cmcl_bnd type=line,boundary
v.centroids bldg_cmcl_bnd out=bldg_cmcl_pol
# add height of the building:
g.region rural_1m -p
v.extrude -t bldg_resid_pol out=bldg_resid_3d height=10 \
elev=el_D792_6m
v.extrude -t bldg_cmcl_pol out=bldg_cmcl_3d height=15 \
elev=el_D792_6m
# showcase:
nviz elev_lid792_1m col=ortho_2001_t792_1m vect=bldg_resid_3d,bldg_cmcl_3d
The result should be similar to the lower right image in
http://www.grassbook.org/gallery/chapters/images.html
Markus