Re: [OctDev] signed distance of point from polygon

[JuanPi <aj...@gm...>]

On Mon, Sep 10, 2012 at 1:01 PM, c. <car...@gm...> wrote:
> Hi,
>
> I need to compute the "signed distance" of a point P from a polygon Q,
> i.e., the distance of P from the polyline including Q with a "+" sign if
> the point is inside the polygon and a "-" sign if it is outside.
>
> I see "distancePointPolygon" in the geometry package computes the distance
> but always returns a positive number. Is there already a function to do
> what I need?
>
> If not, any idea where I can look-up the algorithm to modify "distancePointPolygon"
> according to my needs?
>
> Thanks,
> c.

Hi,

I would not modify the function, but use it together with inpolygon
(in the core geomtry package).

I guess this is what you want
http://agora.octave.org/snippet/FRXH/

Let me know



-- 
JuanPi Carbajal
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"The bad economist pursues a small present good, which will be
followed by a great evil to come, while the true economist pursues a
great good to come, at the risk of a small present evil." - Frédéric
Bastiat
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http://ailab.ifi.uzh.ch/carbajal/