If you can stand it, go slightly smaller than -90,90. do -89,89. That way the chords are < 180 degrees and go in the directions you expect.
Or, build your box of smaller chords, so go from -90 to -45 to 0 to 45 to 90. That will work too. The basic rule is: given two points in geography space, which (naturally) define a great circle, the arc they define is the smaller of the two arcs in the circle. P. On Mon, Jun 14, 2010 at 10:05 PM, <[email protected]> wrote: > > This is also an issue for geometries, but I'm looking for a geography > solution here. > > How can I create a geography that goes from -90 to 90 & crosses the dateline > vs one that goes the other way around the globe & crosses the 0 degree > meridian? > > Either/both is defined by: > > POLYGON((-90 10, -90 -10, 90 -10, -90 -10, -90 10)) > > How can I tell which one I'll get (apart from trying it out) & how do I get > the other, if that is what I want? > > I assume I can use intermediate points along the lines to coerce the > direction I want, but this has some problems in my use case. > > Thanks, > > Brent > _______________________________________________ > 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
