David, Consider using the GEOGRAPHY type if your queries are just going to be ST_DWithin style. That will remove all projection issues.
P. On Wed, Jul 7, 2010 at 11:19 AM, David Jantzen <[email protected]> wrote: > Hey All, > > It's been a couple years but happily I have a reason to work with PostGIS > again! I'm rusty, and this is pretty a basic question, so if you just > specify the chapter in TFM I'll happily go read it. > > I need to do simple point-and-radius searches for some properties in Germany. > Very soon I'll need to do this same thing across Europe and North America, > and some in Asia. My understanding is that the accuracy of such measurements > will degrade as I use projections covering larger and larger geographical > areas. > > So, some questions: > 1) Is there a single global projection that I could use for all such > calculations? How bad would the distortions be and where? > 2) Assuming the correct path is to switch projections depending on area of > focus, what are some strategies for this kind of dynamic switching in SQL > queries? > > Thanks for your help (and patience), > David > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
