[postgis-users] Circle

[pcreso at pcreso.com]

See ST_buffer at http://postgis.refractions.net/docs/ch06.html#id2594743


Buffer generates a buffer zone around an existing geometry a specified distance out (or in if -ve) using a specified number of points. A buffer around a point is a circle if you use enough points, if you could buffer a point with 4 points, you'd get a square centred on the point instead of a circle.


Cheers

  Brent Wood


--- On Sat, 6/14/08, Bob Pawley <rjpawley at shaw.ca> wrote:

> From: Bob Pawley <rjpawley at shaw.ca>
> Subject: Re: [postgis-users] Circle
> To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
> Date: Saturday, June 14, 2008, 11:54 AM
> Is that the only function of the buffer - to create a
> circle?
> 
> Can the buffer modify other functions. If so - what is the
> criteria?
> 
> Bob
> ----- Original Message ----- 
> From: "Paul Ramsey"
> <pramsey at cleverelephant.ca>
> To: "PostGIS Users Discussion"
> <postgis-users at postgis.refractions.net>
> Sent: Friday, June 13, 2008 4:33 PM
> Subject: Re: [postgis-users] Circle
> 
> 
> > Try it and see :)
> > It constructs a circular-shaped polygon around the
> point.
> > P
> >
> > On Fri, Jun 13, 2008 at 4:23 PM, Bob Pawley
> <rjpawley at shaw.ca> wrote:
> >> I'm interested in what the buffer actually
> does.
> >>
> >> Bob
> >>
> >> ----- Original Message ----- From: "Paul
> Ramsey" 
> >> <pramsey at cleverelephant.ca>
> >> To: "PostGIS Users Discussion"
> <postgis-users at postgis.refractions.net>
> >> Sent: Friday, June 13, 2008 3:46 PM
> >> Subject: Re: [postgis-users] Circle
> >>
> >>
> >>> ST_Buffer(ST_MakePoint(x,y),r)
> >>>
> >>> On Fri, Jun 13, 2008 at 3:35 PM, Bob Pawley
> <rjpawley at shaw.ca> wrote:
> >>>>
> >>>> What is the best way of creating a circle?
> >>>>
> >>>> Mu PostgreSQL Developes Handbook susy it
> should be - point and radius.
> >>>>
> >>>> Postgis doesn't seem to have this
> function.
> >>>>
> >>>> Bob
> >>>>
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