[postgis-users] simplify a linestring to n points

[Obe, Regina]

Richard,

I'm curious why you want to do this?

The answer is I think NO, but someone correct me if I am wrong.  I think
the tolerance argument of ST_Simplify is the max distance allowed
between any 2 closest points of the original and simplified.  Though
that's a bit vague to me.

Also I would recommend using ST_SimplifyPreserveTopology if you are
running 1.3.3 with Geos 3+ over ST_Simplify.

I suppose if you insist on min number of points, you could play around
with a combination
of ST_LineMerge and ST_Line_SubString and maybe even throw in a low
number for ST_Simplify

As described here
http://postgis.refractions.net/documentation/manual-svn/ST_Line_Substrin
g.html

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
richard -rw- weinberger
Sent: Friday, November 21, 2008 8:35 PM
To: postgis-users at postgis.refractions.net
Subject: [postgis-users] simplify a linestring to n points

hi list!

does postgis provide a method to reduce/simplify a linestring to a
specific number of points?
i'm aware of st_simplify() but i have to set an lower limit.

thanks,
//richard
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