Hi Charles Thanks for your answer, i can understand a little, i will try to research more. One more time, i would like to say thank you with you and Nicklas.
Cheers On Tue, May 25, 2010 at 6:47 PM, Charles Galpin <cgal...@lhsw.com> wrote: > > On May 25, 2010, at 5:43 AM, nguyen liem wrote: > > > One more question, if i would like to use ST_DWithin in projection WGS84 > and the radius is in 1 meter, how to do that? > > As someone else said it depends on the latitude you are dealing with, but > you take the circumference of the earth at your location and divide by 360 > to get one degree. So at the equator one degree is roughly 69 miles or > 111km. So 0.00001 is 1m at the equator (but is .8m in NJ for example). > > hth, > charles > > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users > -- Liem Nguyen Developer Axon Active Corp. ---------------------------------------------------------------------------- Direct Line : +84 38 948 4645 Fax : +84 38 811 3489 Mobile Phone : +84 168 994 8897 Skype ID : liemnguyendl2204 Email : liem.ngu...@axonactive.net / liemnguye...@gmail.com Web Site : http://axonactive.vn Address : 87 Thang Long Street,Gate 2 Ward 4, Tan Binh District, HCM city, Vietnam.
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