[postgis-users] getting a square/rectangle arround a point

[Daniel Grum]

Daniel Grum schrieb:
> Pavel Iacovlev schrieb:
>> st_intersection(st_envelope(st_buffer(t1.the_geom, $radius)), t2. 
>> the_geom)
>>
>> 2009/8/18 Daniel Grum <daniel.grum at unibw.de>:
>>  
>>> Dear Mailing-List,
>>>
>>> I want to create a square/rectangle around a point-->via 
>>> box2d(geometry) or
>>> buffer(geometry, double precision) for example.
>>>
>>> If I have this rectangle I want to intersect this with another 
>>> polygon-->
>>> saved in the (geodata) table: wald_by column: the_geom, to get 
>>> information
>>> about the area the the "lumberjack" can dig.
>>> The point in the middle of the rectangle = the point that is saved in a
>>> table in my database in the table: holzfaeller in the column the_geom!
>>>
>>> Is this possible to solve?
>>> Do I have to save this calculated square/rectangle in an extra/own 
>>> table?
>>>
>>> Thanks for every help.
>>>
>>> Daniel
>>> _______________________________________________
>>> postgis-users mailing list
>>> postgis-users at postgis.refractions.net
>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>
>>>     
>>
>>
>>
>>   
> I try solve the problem with your message:
>
> SELECT st_intersection(st_envelope(st_buffer('holzfaeller.the_geom', 
> 10, 'quad_segs=8')),wald_by.the_geom);
>
>
> I get this error message:
>
> FEHLER:  parse error - invalid geometry
>
> ********** Fehler **********
>
> FEHLER: parse error - invalid geometry
> SQL Status:XX000
>
> What do you think is the problem in this case.
> Is there a understaning mistake in my SQL order.
>
> Thanks,
> Daniel
>
I thing I solved the problem:

SELECT st_intersection(st_envelope(st_buffer(a.the_geom,1)),b.the_geom)
FROM public.holzfaeller a, public.wald_by b
(WHERE a.gid=3);   //not necessary

Thank You Pavel for the fast answer!