Re: [postgis-users] ERROR: ptarray_area_spheroid: cannot handle ptarray that crosses equator

2011-07-24 Thread Ben Madin
G'day Sarah I'm afraid I'm no expert on geography types, but yes, in some cases st_area can process invalid geometries (like you have described), but they are after all invalid geometries, so it returns 0 . For example, looking at your second example : =# SELECT ST_AREA(the_geom), ST_ISVALID(t

[postgis-users] Geometry almost-equality

2011-07-24 Thread Brendan Morley
Hi all, On my machine the following query gives a "non intuitive" result. What do other people get as a result here? select '010120E610CC2555DBCD206340130F289B72693BC0' = '010120E610B4E386DFCD2063407217618A72693BC0', '010120E610CC2555DBCD206340130F289B72693BC0'::

Re: [postgis-users] ERROR: ptarray_area_spheroid: cannot handle ptarray that crosses equator

2011-07-24 Thread Sarah Berke
I've figured out a little more detail about my ST_Area problem, perhaps this might help someone give me some advice for troubleshooting. To provide a little more background, I've generated several thousand polygons using ST_ConvexHull from collections of points (I've tried both ST_ConvexHull(ST_Col