[OSM-talk] all POIs within a specific radius

[Frederik Ramm]

Hi,

On 08/02/11 14:13, kenneth gonsalves wrote:
> actually I am looking for an sql query.

That would typically be done using the st_dwithin function. That 
function internally makes a bounding box comparison, thereby taking 
advantage of any geographic indexes you might have, and only then checks 
the actual distance.

But note that the "actual distance" is always in projection units, i.e. 
if you have spherical mercator then it will be approximately meters, but 
not really meters.

If you want proper meters, look up st_distance_sphere and 
st_distance_spheroid and/or think about converting from geometry to 
geography data type.

Bye
Frederik