[postgis-devel] Dropped DM (Time) dimension with intersections

[Paul Ramsey]

On Tue, Oct 7, 2008 at 10:57 AM, Kevin Neufeld <kneufeld at refractions.net> wrote:

> Consider a simple 4-point Polygon ((0 0 0, 0 1 0, 1 1 1, 1 0 0)) where the
> third coordinate is raised up to (1 1 1) instead of at (1 1 0).  The surface
> no longer makes sense.  It's actually two triangles (0 0 0, 0 1 0, 1 0 0)
> and (0 1 0, 1 1 1, 1 0 0) on different planes intersecting along the
> breakline from (0 1 0) to (1 0 0).

Or, it's two triangles, joining along the line from (0 0 0) to (1 1
1). Hence the confusion.

P.