[postgis-users] Spatial linking or selection

Giuseppe Broccolo g.broccolo.7 at gmail.com
Fri May 15 05:00:30 PDT 2020


Hi Shao,

Il giorno ven 15 mag 2020 alle ore 11:56 Shaozhong SHI <
shishaozhong at gmail.com> ha scritto:

> Hi, Nicolas,
>
> Thanks.
>
> That is very interesting.  I will test it.
>
> I could not find information on how distance is defined.  0.01 stands on
> what unit?
>
> https://postgis.net/docs/ST_DWithin.html
>

Have a look to this statement in the doc you linked:

"""
For geometry: The distance is specified in units defined by the spatial
reference system of the geometries. For this function to make sense, the
source geometries must both be of the same coordinate projection, having
the same SRID.

For geography units are in meters and measurement is defaulted to
use_spheroid=true, for faster check, use_spheroid=false to measure along
sphere.
"""

Giuseppe.
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