[postgis-users] Randomized PointOnSurface?

[Obe, Regina]

Not that I know of - but I think you can probably simulate it with the
Postgresql random() function and modulo operator (%).  Something along
the lines of

SELECT
ST_PointN(geom_exterior,CAST(random()*ST_NumPoints(geom_exterior)*1000
As integer) % ST_NumPoints(geom_exterior) + 1)
FROM
(SELECT ST_ExteriorRing(ST_GeometryN(the_geom,generate_series(1,
ST_NumGeometries(the_geom)))) As geom_exterior 
	FROM sometable) As sometableexterior



Where sometable.the_geom is either a POLYGON or MULTIPOLYGON

Hope that helps,
Regina

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Webb
Sprague
Sent: Monday, October 15, 2007 2:59 AM
To: PostGIS Users Discussion
Subject: [postgis-users] Randomized PointOnSurface?

Is there a randomized (I guess uniformly) function like PointOnSurface
- such that if you call it repeatedly it will give you different
points in the polygon?  it would be cool for dot maps and other
simulation things.

I looked a little bit, I promise.

-W
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