[postgis-users] geos based spatial queries

[David Blasby]

strk wrote:
> dblasby wrote:
> 
>>Peter Aberline wrote:
>>
>>
>>>select count(*)
>>>from points
>>>where within(points.the_geom, (select the_geom from states where
>>>state_name = 'BigState')) = true;
>>
>>try:
>>
>>SELECT count(*) FROM points WHERE
>>  within(points.the_geom, (select the_geom from states   where 
>>state_name = 'BigState')  AND
>>points.the_geom && (select the_geom from states   where  state_name = 
>>'BigState')
> 
> 
> I'd try:
> 
> SELECT count(*) FROM points p, states s
> 	WHERE s.state_name = 'BigState' -- a btree here
> 	AND p.the_geom && s.the_geom -- a GiST here
> 	AND within(p.the_geom, s.the_geom); -- is really needed ?
> 
> --strk;

The within() is important - "&&" is only bounding box, while 'within()' 
is peformed on the actual geometry.

You could also do a "distance(p.the_geom,s.the_geom) <=0" instead of the 
within.

dave