[postgis-users] line simplication
Eric L. Blevins
eblevins at insight.rr.com
Wed Jan 8 08:10:53 PST 2003
The more I think of this idea the more I would like to see it!
A simplification function that accepts the geometry and a factor of how much
to simplify will be very usefull to anyone using applications like
With this function I think I could decrease the rendering time of my maps by
an order of magnitude while still producing quality maps.
Is there anyone out there who wants to help create this function?
I am willing to devote time to it.
Eric L. Blevins
----- Original Message -----
From: "Paul Ramsey" <pramsey at refractions.net>
To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
Sent: Monday, January 06, 2003 7:47 PM
Subject: Re: [postgis-users] line simplication
> Precisely correct (I think). The best way to the desired result should
> be to implement a Douglas simplification function, and then create a
> view which (a) uses attributes to reduce to just the features of
> interest (interstates, etc) and (b) uses the simplify() function to
> remove unnecessary vertices from the features.
> Eric L. Blevins wrote:
> > I use mapserver and postgis to render data derived from TIGER.
> > This idea is something I could definatly benefit from.
> > Being new to GIS stuff I'll just offer my simple though to the experts
> > there.
> > I would prefer to see something like a simple function.
> > simplify(geometry,simplification_factor)
> > A function that could simplify on the fly would reduce the amount of
> > space needed for a particular geometry. But I suspect it may be at the
> > of speed.
> > However if I wanted to store the simplified version such as in your
> > example below I could simply add a 2nd geometry column and do update
> > database set geom2 = simplify(geom,5);
> | Paul Ramsey
> | Refractions Research
> | Email: pramsey at refractions.net
> | Phone: (250) 885-0632
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> postgis-users at postgis.refractions.net
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