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<DIV dir=ltr align=left><SPAN class=136412622-06082009><FONT color=#0000ff
size=2 face=Arial>Roman,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=136412622-06082009><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=136412622-06082009><FONT color=#0000ff
size=2 face=Arial>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.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=136412622-06082009><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=136412622-06082009><FONT color=#0000ff
size=2 face=Arial>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.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=136412622-06082009><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=136412622-06082009><FONT color=#0000ff
size=2 face=Arial>These links might help</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=136412622-06082009><FONT color=#0000ff
size=2 face=Arial><A
href="http://lists.maptools.org/pipermail/proj/2008-December/004145.html">http://lists.maptools.org/pipermail/proj/2008-December/004145.html</A></FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=136412622-06082009><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV><FONT color=#0000ff size=2 face=Arial><A
href="http://www.spatialreference.org/ref/?search=africa">http://www.spatialreference.org/ref/?search=africa</A></FONT></DIV>
<DIV><FONT color=#0000ff size=2 face=Arial></FONT> </DIV>
<DIV><SPAN class=136412622-06082009><FONT color=#0000ff size=2 face=Arial>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</FONT></SPAN></DIV>
<DIV><FONT color=#0000ff size=2 face=Arial></FONT> </DIV>
<DIV><FONT color=#0000ff size=2 face=Arial></FONT> </DIV>
<DIV><SPAN class=136412622-06082009><FONT color=#0000ff size=2
face=Arial>Leo</FONT></SPAN></DIV>
<DIV><BR></DIV>
<DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left>
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<FONT size=2 face=Tahoma><B>From:</B>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <B>On Behalf Of </B>Smith
Roman<BR><B>Sent:</B> Thursday, August 06, 2009 3:21 AM<BR><B>To:</B> Users
Postgis<BR><B>Subject:</B> Re: [postgis-users] countries with more than one srid
?<BR></FONT><BR></DIV>
<DIV></DIV>
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<P>Hi everyone,</P>
<P></P>
<P>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 ? </P>
<P></P>
<P>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. </P>
<P></P>
<P>A sample query for doing distance calculations on the ellipsoid in
postgis will be helpful. </P>
<P></P>
<P>Cheers,</P>
<P></P>
<P>Roman</P></TD></TR></TBODY></TABLE><BR></BODY></HTML>