[postgis-users] Simple question: How to get projected distance?

[Gustavo Henrique Sberze Ribas]

> I know this is another discussion, but my original first thought on solving
> this mapping problem was to derive, either numerically or in closed form, a
> formula for dx/dlong and integrate it to find relative displacement values.
> For example, a 10 degree shift in longitude at 50 degrees latitude may be
> equal to 100km.  Of course, this is probably what some of these
> parameterizations are accomplishing, but I just haven't looked into it
> enough.
 
 Actually its equal to 716.423km. You can try using distance_spheroid
to achieve what you want.

select distance_spheroid('SRID=4326;POINT(0 50)','SRID=4326;POINT(10 50)','SPHEROID["WGS 84",6378137,298.257223563]');

--
Gustavo
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