On Thu, Oct 19, 2006 at 09:31:40PM +0530, Sandeep Kumar Jakkaraju wrote:
> I use postgis to wipe my ASS ...
> no good documentation ...
If you find the documentation lacking then please consider posting
to postgis-users with suggestions for improving it. Even better,
submit a patch :-)
> in what units is the result of distance(geometry,geometry)..
http://postgis.refractions.net/docs/ch06.html#id2526205
"Return the cartesian distance between two geometries in projected units."
If the geometries are in degrees then distance() returns degrees;
if they're in meters then distance() returns meters; if they're in
cubits then distance() returns cubits.
> what is distance_sphere(geometry,geometry)..
http://postgis.refractions.net/docs/ch06.html#id2528534
"Returns linear distance in meters between two lat/lon points."
> when u give same geometry as both parameters it gives a non-zero
> value ....
test=> SELECT distance(GeomFromText('POINT(12 34)'), GeomFromText('POINT(12 34)'));
distance
----------
0
(1 row)
test=> SELECT distance_sphere(GeomFromText('POINT(12 34)'), GeomFromText('POINT(12 34)'));
distance_sphere
-----------------
0
(1 row)
If you're getting unexpected behavior then please post a test case
to postgis-users.
--
Michael Fuhr