I had similar problems with census Canada data. Some of them took over
a week to complete.
Loretta
Hello,
I am looking to take the standard Tiger/Line Shapefile of US counties, which
includes major waterways in the border of counties (especially an issue
around the Great Lakes) and truncate the c
You know this is a similar problem to what I was experiencing when I
asked what was the difference between ST_Union and ST_Collect. When I
got the topological errors thrown from the ST_Union, there was a NULL
result in the geometry field for each area that had an error. See
http://postgis.refract
o why you can collect just any geometries
> because the function doesn't care about what it is collecting. But
> whenit comes to melting the geometries together it is more tricky
> and the
> function has some demands for the algorithm to work.
>
> HTH
> Nicklas
>
Hi,
Yes, thanks Jamie, that is indeed what I meant. Didn't proofread the
message well enough!
Regards,
Loretta
- Original Message -
From: James DeMichele
Date: Friday, September 10, 2010 6:50 pm
Subject: Re: [postgis-users] ST_Union vs ST_Collect
> Hello, Loretta, when you said: " re
Hi Henri,
Did you try using ST_MULTI and then check the output? I have had
success with this.
Regards,
Loretta
Hello,
I have a collection of polygons none of which overlap except perhaps on parts
of their outer rings.
I have the impression this cannot be turned into a multipolygon because th
Well that was a marathon, but I think we have it licked! Thanks to
everyone for their suggestions. It probably would be simpler to use
Andrea's suggestion for using ST_CollectionExtract, but we are not on
PostGIS version 1.5 yet, so here is what I found worked in version 1.4
to get all intersecti
: Re: [postgis-users] Problem cleaning invalid geometries
> You could use ST_Dump() to split your multipolygon up and then run
> validity check/fix on the individual components...?
> P
>
> On Fri, Aug 20, 2010 at 9:44 AM, L Bogert-OBrien
> wrote:> Hi,
> >
> > I am
Hi,
Just another update for this. The scenario described first with 3 rows
for each census tract in the new table was for when there was a lake or
bay. I have also found that there can be many rows in the new table
when an island is surrounded by many polygons in the water file.
Thanks again fo
In a previous posting, I saw the following suggestion:
>
> ...you could do something like this:
> select count(*)
>from
> public.table1 as a,
>public._sample_extent as b
>where
> ST_Intersects(a.geom,b.geom)=true
>
I was wondering, doesn't
"WHERE
Hi,
I am just wondering if there is a way to minimize the extent on which
the cleangeometry() function will act, or rewrite it so that it only
checks out the parts of the multipolygon near the problem area, rather
than having to wait for it to check the validity of all the pieces of
the multipolyg
Just an update to let list users know that the call to cleangeometry()
did return after a very long time--almost 17 hours for one of my files
and more than a day for another.
Regards,
Loretta
>I am not sure what you are trying to say with this, but the geometry
>that I am trying to clean is a mul
I am not sure what you are trying to say with this, but the geometry
that I am trying to clean is a multipolygon, not a collection. Yes, it
is very big and has many points in the multipolygon, since it is the
Baffin region, but it is not a collection. ST_geometrytype returns
multipolygon for it.
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