[postgis-users] RE: HELP 3d spatial bounding box

[ebcorder at rockwellcollins.com]

Thanks Steve,

That helps me to understand.  I have Matlab to handle the math.   I was
just hoping I could create 3d indexes with the database.   I still need a
database for its relationship capability.  I wanted the Database to hold
weather cell objects with the objective of tracking storm movement.   An
alternative for me would be a 2d-1d relationship thereby splitting 3d into
2d-1d.   I'll check out the modeling stuff.   This site has been great..
Thanks for the help.


Hi Elwood,

The fundamental problem here is that polygons are basically 2D planar
objects, even if they are draped over a 3D contour. While postGIS has
the ability to carry with these planar objects some additional
information like Z values and M values, all the implementation has
underlying assumptions that things are basically planar in nature.

If you need geometric/volumetric calculations in 3D then you probably
really need something that does solid modeling. Check out:

http://www.google.com/search?hl=en&q=solid+modelling+opensource&btnG=Google+Search

for some ideas, these may be what you need. I do not think postGIS will
even have something as simple as the 3D intersection of two plane that
results in a line, point or polygon unless they are coplanar and the Z
values are ignored.

-Steve W.
Elwood Cordery
Rockwell Collins
Contract Software Engineer
319-295-8248