Hi all,
I wrote code years ago in C that would take a cloud of 3D points insert
them into a Delaunay triangular surface, then slice the surface
triangles with a plane(s) into intersecting edges and then composite
rings from the edges. It seems like we are very close to being able to
do this in PostGIS. I'm not sure if we have the Delaunay
triangularization yet.
I'm thinking of something like:
select b.z, a.* from
st_buildarea(
st_collect(
intersection(
delaunay_triangles(
select the_geom from points),
st_translate(
st_expand(select extents(the_geom) from points, 0.1),
0.0, 0.0, b.z
)
)
)
)
) as a,
(select 1.0 * generate_series(2, 10, 2) as z) as b
group by b.z;
So I'm thinking of something like this is the use case, where this would
create contour rings for Z at 2, 4, 6, 8, and 10 based on the
triangulated surface created from the points. My SQL is probably broken,
but it is only to present the idea.
So any ideas on how to do this now?
Or if Delaunay triangularization will get added to PostGIS or GEOS?
Thanks,
-Steve
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