On 19 May 2010 13:06, Marcus Wolschon <mar...@wolschon.biz> wrote: > Hello, > > what projections do you use to calculate distances (in meters) in postgis? > I have some code here that tried to use 27700 but that is not defined > on all inhabited continents of this planet. > An error of at most 25% would be acceptable as tis is just about search > -areas and not street-length. >
It all depends what kind of distance you are trying to get. One easy way is to use the FindUTM of the area you are looking for http://trac.osgeo.org/postgis/wiki/UsersWikiplpgsqlfunctionsDistance The next possible trick is to switch your column type to geography if you have postgis 1.5. It would mean that all postgis function relating to length and areas would start reporting data in meters. Emilie Laffray
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