[GRASS-dev] GV_VOLUME: does it exist?

[Hamish]

Benjamin Ducke wrote:
> could anybody enlighten me about the status of the GRASS 3D
> geometry type "GV_VOLUME"? I assume this is meant to be the equivalent
> of the 2D "GV_AREA", i.e. GV_KERNEL + GV_FACE(S)?

AFAIU it is only really used by NVIZ so far for displaying 3D vector
volumes*, but I think it is important to keep it in a state ready to be
implemented :) 

[* e.g. v.in.dxf (not -f) -> nviz
 http://bambi.otago.ac.nz/hamish/grass/screenshots/nyc3d_nviz3_midtown.png
]

> Is there some actual Vect library level support for processing
> such geometries or does GV_VOLUME just exist as a symbol for
> completeness' sake? So far I could not spot it in the "type="
> option of any GRASS module.

not much as far as I've found, but hopefully that will change one day.
better defining it's purpose would definitely help.

one question I've always had: do kernels exist as centroids within a
closed volume (center of empty soccer ball), or one of the surface of
every 3D face? (ie on on each hexagonal/pentagonal patch of the soccer
ball)


Hamish