Thanks a bunch Paul. I did arrive those findings after I posted the query. Now I am thinking how to do what I want to do if I want the polygon to be with the great circles in postgis.
Any pointers. Regards, Mahesh On 13 June 2011 17:49, Paul Ramsey <[email protected]> wrote: > And relatedly, here's why Google Earth gives the wrong visual answer. > > http://blog.opengeo.org/2010/08/10/shape-of-a-polygon/ > > P. > > On Mon, Jun 13, 2011 at 9:47 AM, Paul Ramsey <[email protected]> wrote: > > You're thinking in straight lines, not great circles. Here's what your > > "box" actually looks like > > > > > http://www.gcmap.com/mapui?P=10N+170E-10N+0E%2C%0D%0A10N+170E-5N+170E%2C%0D%0A5N+170E-5N+0E%2C%0D%0A5N+0E-10N+0E&MS=wls&DU=mi > > > > I can see how that could hit your Russian foot print. > > > > P. > > > > On Mon, Jun 13, 2011 at 6:54 AM, Mahesh Ghule <[email protected]> > wrote: > >> Hello Guys, > >> After lot of head scratching I have decided to post this email. > >> We have a PostGIS 1.5.1 on PostgreSQL 8.4 > >> select > >> > ST_AsText('0105000020E6100000010000000102000000020000009FAEEE586C8C5240029CDEC5FBF94D406B44300E2EDB5140D591239D81D14C40'::geography) > >> as TextFootPrint, > >> > >> > > ST_Intersects('0105000020E6100000010000000102000000020000009FAEEE586C8C5240029CDEC5FBF94D406B44300E2EDB5140D591239D81D14C40'::geography, > >> ST_GeographyFromText('POLYGON((0 10,170 10,170 5,0 5,0 10))')) as > >> Intersects; > >> yields following result > >> TextFootPrint > >> | Intersects > >> > ------------------------------------------------------------------------------------------------------------------- > >> MULTILINESTRING((74.194113 59.952996,71.424686 57.636768)) | > t > >> > >> Which as I understand is not correct. The footprint is a line string > >> somewhere over Russia and the Polygon is a band in north hemisphere just > >> above equator. > >> Also when I visualise the both geographies as KML in google earth I can > see > >> them thousands of miles apart. > >> This is just one example footprint where I have tens of thousand more in > my > >> DB like this. > >> Please help me understand what is going on? > >> > >> Regards, > >> Mahesh > >> > >> _______________________________________________ > >> 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 >
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