<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7652.24">
<TITLE>RE: [postgis-users] Dateline and polar regions and any other spatialgotchas</TITLE>
</HEAD>
<BODY>
<!-- Converted from text/plain format -->
<P><FONT SIZE=2>Pauk --<BR>
<BR>
Thanks for the advice ... it seems as if getting a decent SRID (or set of them) will be a major part of the battle, then, but it sounds as if the underlying GEOS suite doesn't have issues if it is handed sensible data.<BR>
<BR>
Greg W.<BR>
<BR>
-----Original Message-----<BR>
From: postgis-users-bounces@postgis.refractions.net on behalf of Paul Ramsey<BR>
Sent: Wed 6/27/2007 10:06 AM<BR>
To: PostGIS Users Discussion<BR>
Subject: Re: [postgis-users] Dateline and polar regions and any other spatialgotchas<BR>
<BR>
There are definitely issues with dateline and poles when working in<BR>
4326, since the coordinates are treated as planar, not polar.<BR>
Workarounds for the dateline are relatively easy to do, usually in the<BR>
form of double-entry inserts (we should probably write a standard<BR>
trigger for doing that (if something crosses the dateline, insert it<BR>
twice, once on each side of the plane)). The poles I think are a harder<BR>
problem.<BR>
<BR>
P<BR>
<BR>
Gregory Williamson wrote:<BR>
> Most of the work our company (GlobeXplorer) has done with postGIS has<BR>
> been in US markets where such things as dateline math isn't much of an<BR>
> issue. We use SRID 4326 to store the data in.<BR>
><BR>
> We (DigitalGlobe) are evaluating PostgreSQL and Oracle for a largish<BR>
> project using data all over the planet, and before I make any bald<BR>
> assertions I thought I'd ask and see if there are:<BR>
><BR>
> a) know issues with datelines or other gnarly parts of the world ?<BR>
><BR>
> b) workarounds ?<BR>
><BR>
> Thanks for any info ... tried trolling the website and didn't find any<BR>
> caveats, but the mail list archive isn't really searchable so I am<BR>
> hoping this is not a FAQ (if it is, point me at it!).<BR>
<BR>
<BR>
--<BR>
<BR>
Paul Ramsey<BR>
Refractions Research<BR>
<A HREF="http://www.refractions.net">http://www.refractions.net</A><BR>
pramsey@refractions.net<BR>
Phone: 250-383-3022<BR>
Cell: 250-885-0632<BR>
_______________________________________________<BR>
postgis-users mailing list<BR>
postgis-users@postgis.refractions.net<BR>
<A HREF="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>
<BR>
</FONT>
</P>
</BODY>
</HTML>