[postgis-users] what is the units of distance parameter inthe buffer function

[Bruce Rindahl]

The third parameter defines how close to a circle the buffer will be.  There
is no “circle” in PostGIS (or most GIS software) – it is approximated by a
series of lines.  The default value of 8 means a circle will be approximated
by 32 line segments.  If you specified this as 1 you would get 4 points or a
square.  If the buffer value is very large you might need to increase the
value  to more than 8.

Bruce

 

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From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Pedro
Doria Meunier
Sent: Saturday, December 02, 2006 10:13 AM
To: 'PostGIS Users Discussion'
Subject: RE: [postgis-users] what is the units of distance parameter inthe
buffer function

 

Kumar,

 

If your geom is lat/lon 1=1 degree

As to the 3rd argument  it’s a mystery to me too


>From the manual:

The optional third parameter sets the number

of segment used to approximate a quarter circle (defaults

to 8).

 

What’s this good for?!

 

Pedro.

 

From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Sandeep
Kumar Jakkaraju
Sent: sábado, 2 de Dezembro de 2006 16:38
To: postgis-users at postgis.refractions.net
Subject: [postgis-users] what is the units of distance parameter in the
buffer function

 


what is the units of distance parameter in the buffer function  ...

buffer(geom,distance,[integer])   ---> buffer(GEOMFROMTEXT('POINT(28.0
79.0)'),1);

if my geom is in lat/lon ..... how much will be 1 !! 

can some one throw more light on the 3 rd optional parameter !!! the manual
is not clear !! 

-- 
Sandeep Kumar Jakkaraju 
WeBlog:
http://jakkarajus.blogspot.com  <http://jakkarajus.blogspot.com> 

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