[GRASS-user] Create 3d models of buildings for use in Google Earth

Hamish hamish_nospam at yahoo.com
Mon Aug 13 23:55:20 EDT 2007

Intengu Technologies wrote:
> I have seen the following posts,
> http://grass.itc.it/pipermail/grassuser/2006-May/034214.html and
> http://grass.itc.it/pipermail/grass-dev/2006-June/023820.html
> I have access to orthorectifed high res imagery of towns and would
> like to start creating 3d models of buildings - would actually prefer
> to automate this process as much as possible.
> I do not have access to polygons of buildings with height.

you need to extract building footprints as 2D polygons then assign a
height to each.

- load imagery into GRASS.
- run a edge detection filter over imagery to automatically make polygons.
   (?? I'm unsure of which module to use, other than custom r.mfilter)
- v.clean to remove small areas (false positives)
- v.digit with ortho image as backdrop for more cleaning (delete non-
- add a "stories" column to 2D polygon vector
- give data or start as all as one column
- v.extrude as in above URL.

> Once models are created they will be viewed on GoogleEarth.

from above URL:
 v.out.ogr format=KML type=face

GRASS 3D vector building NVIZ screenshots:


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