[postgis-users] line simplication

Paul Ramsey pramsey at refractions.net
Mon Jan 6 16:47:21 PST 2003

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 out
> 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 storage
> space needed for a particular geometry.  But I suspect it may be at the cost
> of speed.
> However if I wanted to store the simplified version such as in your number 2
> 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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