Re: Question Regarding Geometric Operators/Function . . .

On Thu, Aug 29, 2002 at 15:51:13 -0400,
  "Peter E. Chen" <pchen3@jhmi.edu> wrote:
> Hey Everyone,
>
> Does anyone know if there is a geometric operator/function that will allow
> me to determine if a line segment and a point overlap?  By overlap I mean
> that the point lies on the line segment.  I can't seem to do this with the
> available geometric operators.

There probably isn't an operator to do this because those types are based
on floating point data and you won't be able to reliably determine this.

> Also, can someone explain to me the difference between how postgres defines
> overlap and intersect for its geometric operators/functions.

I am not an expert here, but typically an overlap is something that this
testable (and would be true or false), while an intersection is a set
(and would be some geometric object).