[postgis-users] Seamlessly handling lat/long coordinates

Craig Miller craig.miller at spatialminds.com
Fri Aug 26 10:22:03 PDT 2005


In order for Lat/Long calculations to be done accurately it requires that
the calculations be done on an ellipsoid (3D).  Projected coordinates are
projected onto a 2D cartesian plane allowing for all the calculations to be
done using simple Cartesian geometry.  Computations on an ellipsoid are both
more difficult to implement, and slower due to their complexity.

 

--Craig

 

 

  _____  

From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Lance
Arlaus
Sent: Friday, August 26, 2005 2:06 AM
To: 'PostGIS Users Discussion'
Subject: [postgis-users] Seamlessly handling lat/long coordinates

 

All-

 

I wanted to follow up on a thread from the other week.  I don't know if this
question is appropriate for this list or if it belongs on devel instead.

 

I'm new to GIS, but I can't help wondering what it would take to enable
PostGIS to easily handle lat/long coordinates.  It seems like such a common
use case that I'd really like to understand what the hurdles are.  It would
be great to have the ability to get distances, create buffers, and perform
boolean operations without going through intermediate transformations.

 

Can someone give me some more insight into the problem?  DB2 Geodetic was
mentioned as a product that already accomplishes this, so it sounds like
it's possible.

I hope this doesn't come off as obnoxious - that's certainly not the intent.

 

Thanks,

Lance

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