Daniel Grum schrieb:
Daniel Grum schrieb:
Pavel Iacovlev schrieb:
st_intersection(st_envelope(st_buffer(t1.the_geom, $radius)), t2.
the_geom)
2009/8/18 Daniel Grum <[email protected]>:
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
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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!
The problem now:
this order calculates a lot of points and the intersection with the
layer "wald_by" can't be solved because the geo data typ is:
GEOMETRYCOLLECTION.
I tried to generate a rectangle with ST_GeomGromText instaead of the
st_buffer that generates a circle:
ST_GeomFromText('POLYGON((st_x(a.the_geom)-2.0
st_y(a.the_geom)+2.0,st_x(a.the_geom)+2.0
st_y(a.the_geom)+2.0,st_x(a.the_geom)+2.0
st_y(a.the_geom)-2.0,st_x(a.the_geom)-2.0
st_y(a.the_geom)-2.0,st_x(a.the_geom)-2.0 st_y(a.the_geom)+2.0))')
PostgreSQL don't alerted me with a mistake, but if I would look for the
generated data, PostgreSQL isn't able to do this and said "Bricht ab".
What can be the reason for this?
Thanks
Daniel
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