[GRASS-user] Extraction 3D vectors ridges/Thalweg from raster DEM ?

[Markus Neteler]

On Fri, Dec 13, 2013 at 4:47 PM, Micha Silver <micha at arava.co.il> wrote:
> As far as I know, the shapefile format does not really support 3D vectors.

To my knowledge you can write out the 3D SHAPE file right away:

http://grass.osgeo.org/grass64/manuals/v.out.ogr.html
-z Create 3D output if input is 3D (applies to Shapefile output only)

EXAMPLES
-> Export to Shapefile
--> Export 3D faces from GRASS vector map to Shapefile format,
automatic 3D setting:

   v.out.ogr input=objects_3d type=face dsn=faces_3d.shp -z

hope this helps,
Markus