[postgis-users] degrees between points

[Nicholas Lan]

Thanks for your response. However, this is also not giving the answer I
expect. As the input you show illustrates, this input gives a response of 45
degrees, whereas the answer should be 90 degrees if 90 90 corresponds to the
north pole and 0 0 a point on the equator. I have also tried this with a
point 89 89 with a similar problem. A point 90 0 does however give the
correct result of 90 degrees. Do I still have the wrong idea about what the
function should do?

Regards
Nicholas Lan

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Nicolas
Ribot
Sent: Wednesday, January 16, 2008 6:07 PM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] degrees between points

> The following function seems to be the one:
>
> ST_azimuth(geometry, geometry)
> Returns the azimuth of the segment defined by the given Point
> geometries, or NULL if the two points are coincident. Return value is
> in radians.
>

Or azimuth():

select azimuth(geomfromtext('POINT (0 0)', 4326),
geomfromtext('POINT(90 90)', 4326));
      azimuth
-------------------
 0.785398163397448
(1 row)

or
select degrees(azimuth(geomfromtext('POINT (0 0)', 4326),
geomfromtext('POINT(90 90)', 4326)));
      degrees
-------------------
 45
(1 row)

Nicolas
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