[postgis-users] Problem with convex hulls that cross the dateline

[Paul Ramsey]

On Tue, Sep 6, 2011 at 10:18 PM, Paragon Corporation <lr at pcorp.us> wrote:
>  Sarah,
>  >  I'm having trouble making convex hulls that cross the international
> dateline. Imagine 4 points making a square with the international dateline
> running down the middle--I would like the convex hull to be that square, but
> instead I get a giant rectangle that goes across the entire planet. I've
> done some reading, and it sounds like GEOS generally has a hard time dealing
> with the dateline--is that accurate?
> Yes GEOS  only deals with planar coordinates.  Geography is the only
> geodetic aware type and there is no ConvexHull function for it.

Although you could hack one up easily enough by copying the ideas in
ST_Buffer(geography)

P