[postgis-users] WGS84 to meters

[Nicolas Ribot]

> Hi,
>
> Suppose we want to store geometries that are all over the globe, and we want
> to calculate their surfaces and their mutual distances, in (square)meters.
> The rounding of the globe may be disregarded.
> Can it be done?
>

Hi,
Yes for the distance, as Postgis provides both distance_sphere and
distance_spheroid functions (distance_spheroid is more accurate, taken
the "real" shape of earth into account, but takes a longer time to
execute.)
Distance is computed between points, not between geometries, so will
either have to take the centroid of your geometry, or compute the
distance for individual coordinates).

No for surfaces. You will have to project your data into a planar
projection system to do so (UTM for instance). This thread may be
useful in your case to find the correct UTM zone according to your
objects coordinates:

http://www.nabble.com/function-to-find-UTM-zone-SRID-from-POINT-td1772300.html

Nicolas