[postgis-users] countries with more than one srid ?

[Paragon Corporation]

Roman,
 
I think you will want to stay away from ellipsoid for now or at least until
PostGIS 2.0 (or 1.5 comes out).  Those in current PostGIS just deal with
point geometries and not terribly well.
 
I think your best bet is to find a spatial ref that covers all of Nigeria.
It won't be quite as accurate but will save you having to worry about
dealing with 2 or 3 sets of spatial refs.
 
These links might help
http://lists.maptools.org/pipermail/proj/2008-December/004145.html
 
http://www.spatialreference.org/ref/?search=africa
 
You could formulate your own from proj constructs that is more accurate than
above (and covers the 2 srids you mentioned), but that's not my strength
 
 
Leo

  _____  

From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Smith
Roman
Sent: Thursday, August 06, 2009 3:21 AM
To: Users Postgis
Subject: Re: [postgis-users] countries with more than one srid ?



Hi everyone,

Since I intend placing all my states data in one table, are u suggesting
that I leave my data in wgs 84 (lon & lat) then do my distance calculations
on the WGS 84 ellipsoid ? 

How can this be done in postgis ? The distance calculations I need to do in
my application are nearest neighbour and where are my queries. 

A sample query for doing distance calculations on the ellipsoid in postgis
will be helpful. 

Cheers,

Roman


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