On 07/01/2011 05:58 PM, Brian Sanjeewa Rupasinghe wrote:
Hi,
I am using following SQL query to retrieve the coordinates of the first
vertex of the first multipolygon in the
table Building_Poly.
select X(pointN(ExteriorRing(GeometryN(the_geom,1)),*1*)),
On 11/02/2010 01:48 PM, Jan Saalbach wrote:
Dear All,
is there a function to easily subtract a polygon from a polygon. Both
are rectangles.
The scenario:
Two overlapping polygons identified by ST_INTERSECTS.
Creating a third one from the overlapping area via ST_INTERSECTION.
Subtract the
On 08/18/2010 02:51 PM, Mauricio Miranda wrote:
1) Create the geometry_column as generic type GEOMETRY. It will allow you
to store any kind of geom.
Related question: is it possible to create a geometry index on such a
column ?
--
Maxime
___
On 07/28/2010 10:15 PM, Jeff Adams wrote:
OK, I finally have it down to a manageable use case. Union these 16
linestrings, you get a topology exception. Remove any one of them, you
don't. What the heck can I do about this? Simplifying and snapping to
grid, at any reasonable precision, did
On 05/10/2010 05:32 PM, Charles Galpin wrote:
I searched the archives and saw this asked in 2005 but it didn't appear to
have a resolution then. I have two points in a multipoint geometry which
represent the start and end point of road segments that I need to extract the
points back out
On 04/15/2010 01:37 PM, Marc Jansen wrote:
Hi Birgit,
I can confirm your results on
To help tracking down the bug: I have the same problem (areas
0.001953125 or 0 for the query on the pastebin) on :
PostgreSQL 8.4.3 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC)
4.4.3 20100316
Paul Ramsey wrote:
Last message from 2009, the videos of sessions have been linked into
the main website now and are all online, have a look, especially at
the State of PostGIS :) http://blip.tv/file/2788616/ Sydney was a
grand conference, I hope all you members of the PostGIS family are
Paul Ramsey wrote:
Other planets could be handled when arbitrary SRID values are allowed.
So, it's an obvious extension, but one which someone is going to
probably have to step up and fund. However, even with the current
version, you could support Mars or Venus at compile time, easily
enough,
Paul Ramsey wrote:
Well, if they're fictive, then there's no reason you can't use WGS84.
Fun, who gets to be Slartibartfast and design your world :)
I don't get the point. Doesn't WGS84 only apply to the Earth ?
--
Maxime
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postgis-users mailing
Rick wrote:
WGS84 defines an ellipsoid that is used for a reference to approximate
the shape of the earth. If you are talking about a fictional planet,
you can use anything, a sphere.
A real planet, at least one that is out of round enough, and with data
good enough, for the data available
Paul Ramsey wrote:
Last message from 2009, the videos of sessions have been linked into
the main website now and are all online, have a look, especially at
the State of PostGIS :) http://blip.tv/file/2788616/ Sydney was a
grand conference, I hope all you members of the PostGIS family are
Paul Ramsey wrote:
Martin++. If you don't mind the complexity of writing your own little
query engine, having all the features in memory, as JTS
PreparedGeometries, with an STRTree on top of them (assuming your
collection is more than a few items) you'll get better performance
than in
Paul Ramsey wrote:
Use ST_Centroid() then. It's just the mid-point of the bbox, so it's
fast to calculate.
It might be outside the polygon though.
--
Maxime
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postgis-users@postgis.refractions.net
Marco Lechner - FOSSGIS e.V. wrote:
is there a function that returns the number of points of a geometry?
LINESTRING(9.6567389 47.8442843,9.6572511 47.8443736,9.6570058
47.8449885,9.6565007 47.8449207,9.6567378 47.8442853) = 5
LINESTRING(8.9289313 48.6910326,8.9289313 48.6910326) = 2
...
Marco Lechner - FOSSGIS e.V. wrote:
exactly. thnx. by the way: what's the difference between st_numpoints()
and st_npoints()? The results in my case are the same
From the doc of ST_NumPoints :
« From 1.4 forward this is an alias for ST_NPoints which returns number
of vertexes for not just line
G. van Es wrote:
I want to have a list of wich geometry of a certain type is touching or
crossing another type.
Can someone point me in the right direction?
Hi,
If I understand your problem you want to find for each geometry in your
table which geometries intersect with it ?
This can be
Michael Smedberg wrote:
You can use the astext function to get the WKT (well known text.)
E.g. you could do something like:
SELECT astext(the_geom) FROM library.dgm_process
which would return a textual representation of the geometries.
ST_GeomFromText is the opposite of astext- it'll
Bob Pawley wrote:
The geometry comes up true for st_isvalid and yes the points are
covering the geometry and beyond.
Did you try with other functions like ST_Intersecs or ST_Covers ?
--
Maxime
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Bob Pawley wrote:
Hi
I have a table holding a number of rows of points which I want to
translate from covering Box 1 to covering Box 2.
When I use the following all of the points are translated to the same
central position (200 points stacked upon each other)
insert into fluids
Bob Pawley wrote:
select st_astext(graphics.point_grid.the_geom)
from graphics.point_grid, library.dgm_process
where library.dgm_process.process_number = '1'
and st_within(graphics.point_grid.the_geom, library.dgm_process.the_geom);
Any thoughts would be appreciated.
Hi,
From the
Bob Pawley wrote:
I have tried it with the point and geometry reversed with the same result.
Perhaps, I am not looking at this the right way.
According to the manual
st_within Returns TRUE if geometry A (points) is completely inside
geometry B ( geometry).
If it scans the list of
Bob Pawley wrote:
Funny this does work when I include st_box2d as in -
st_within( graphics.point_grid.the_geom,
st_box2d(library.dgm_process.the_geom))
However, this will include points within the box yet outside of the
actual geometry.
It's hard to help without some additionnal data.
Bob Pawley wrote:
Hi
In order to have only one row, I have a number of points stored in a
table as st_union.
Is there a method of breaking the points out of the st_union geometry
so that I can access the points individually.
I want to use the points as a reference for st_within.
Simon Greener wrote:
Did you move to PostGIS from any other spatial database like Oracle
Locator/Spatial?
No I didn't. Before choosing PostGIS I read what was said here and there
about various geospatial databases. I was convinced once I gave a try to
PostGIS : so simple to install et to get
Juergen Lorenz Simon wrote:
Hi,
I have a nut to crack and i'm not finding anything suitable in the
PostGIS documentation. The problem is as follows:
I have a POLYGON G and a POINT P. I'd like to find the closest point to
P on G (not in, ON). Is there a quick way of doing this with the
Daniel Grum wrote:
The SQL-Skript:
UPDATE einheiten_und_bewegungen
SET the_geom = (SELECT
ST_Line_SubString(ST_LineMerge(line.the_geom),(1-((Length(line.the_geom)-1000)
/Length(line.the_geom))),1)
FROM public.einheiten_und_bewegungen line
WHERE
eehab hamzeh wrote:
SELECT asEwkt(ST_Multi(ST_Union(ARRAY(SELECT the_geom FROM faces_obj;
Hi,
Did you try to simply do :
SELECT ST_Multi(ST_Union(the_geom)) FROM faces_obj;
The ST_Union function will merge polygons if it is possible.
BTW, some of you polygons are invalid (check them
eehab hamzeh wrote:
SELECT ST_Multi(ST_Union(the_geom)) FROM faces_obj;
MULTIPOLYGON(((-14161.75 1941.76 2750,-14161.75 2241.76 2750,-9336.75 2241.76
2600,-9336.75 1941.76 2750,-14161.75 1941.76 2600)))
these polygons are representing 3D box
i need them to be as one record (mutlipolygon
Tuomas Ruohonen wrote:
Compare two rows in table, when result changes more than 2 query shows
only those rows. In this case query ignores 25,25,25,24,23 and shows
only 26,24 and 21. There should be always one number only if the number
is same, like 24 and 24, shows only one 24.
Is this even
On 09/22/09 13:44, Tuomas Ruohonen wrote:
Hi all,
How I can get POINT where two linestrings are crossing ? I am now using
st_crosses to linestrings.
Hi,
ST_Intersection seems to be what you're looking for :
http://postgis.refractions.net/documentation/manual-1.4/ST_Intersection.html
--
On 09/21/09 18:50, eehab hamzeh wrote:
Hello
Is there are any command work like st_makeline to create a multipolygon.
I have a table with a different record of polygon. I need to create
multipolygon from them
Any hint or directions
SELECT ST_Union(geom) FROM table;
This will perform the
Hi,
On 08/19/09 15:11, Ben Madin wrote:
Thanks Fred,
I have also had this problem, but I don't understand how to handle the
'set' that is returned.
ST_Dump should return a two-column list :
# SELECT ST_Dump('MULTILINESTRING((0 0, 10 10, 20 20), (100 100, 200 200, 300
300))');
On 08/19/09 16:24, Andrea Peri 2007 wrote:
Hi Frank,
thx for suggestion.
I try with ST_Dump using:
(ST_Dump(geom)).geom
But unfortunately it give me again all segments with only 2 vertex :(
So from 1 MultiLineString with 2 parts each with 20+ vertex give me many
LineStrings with
On 08/15/09 15:34, tommy408 wrote:
I'm about to insert a polygon into a large table. Whats the fastest way to
find if this polygon will overlap another polygon inside the table?
Hi,
What do you mean exactly by 'overlap' ? Has it to totally cover another
polygon ? Or just simply intersect
On 08/05/09 12:46, Paragon Corporation wrote:
Mark,
To add I think Simon's dataset was too big to go thru 1.3 at a decent time
(as I recall think its about 3000 polygons he's dealing with). I think I
have run into some of these issues myself in my torture tests but ignored
them since they
On 08/04/09 17:39, Kevin Neufeld wrote:
Nice. I posted your function to the trac ticket for this function.
(http://trac.osgeo.org/postgis/ticket/76)
I am a little concerned about scalability, but we'll see what the team
thinks.
Good work.
Thanks. However Robe (cf ticket) and you are
On 08/05/09 14:47, Maxime van Noppen wrote:
Thanks. However Robe (cf ticket) and you are right, there is a
scalability issue. For the sake of the test I've implemented the ST_Dump
function in plpgsql with a recursive call (as my_ST_DumpPoints is) and
in some very bad cases it's very slow
On 07/31/09 20:20, Kevin Neufeld wrote:
Unfortunately, I think your solution is overly simplistic.
Of course, it is a little function dedicated to a specific use case for
my program.
I think the
community is after something that mimics the ST_Dump and ST_DumpRings
functionality.
I agree.
Hi,
Is there a function similar to what ST_Dump does for MULTI* geometries
on simple geometries ? Something that would behave like :
# SELECT ST_SimpleDump('LINESTRING(0 3, 1 4, 1 5)');
st_simpledump
POINT(0 3)
POINT(1 4)
POINT(1 5)
I
On 07/31/09 18:00, Fred Lehodey wrote:
Hi Maxime,
http://postgis.refractions.net/documentation/manual-svn/ST_PointN.html
Hi,
ST_PointN doesn't work as stated. I must iterate over points to get them
all which I wish I could avoid.
--
Maxime
On 07/31/09 18:36, Kevin Neufeld wrote:
Unfortunately, not yet. ST_DumpPoints is on the TODO list as it would
definitely be useful.
http://trac.osgeo.org/postgis/browser/trunk/TODO?rev=3485#L31
http://trac.osgeo.org/postgis/ticket/76
Cheers,
Kevin
I was looking to PostGIS source code
On 07/24/09 15:49, Kevin Galligan wrote:
I'm sure there's something simple I'm missing here, but we've hit the
pull hair out stage, so I'm hoping there's a kind soul out there
that can clear things up.
I've ran the example you give that you give as example and get results :
# select
On 07/11/09 18:57, Paragon Corporation wrote:
Maxime,
ST_AsText does not produce the fidelity of the geometry. It truncates
floating points and I think where they truncate between GEOS and PostGIS is
different. GEOS and PostGIS do not share the same WKT writers.
My question is -- have
Hello,
I've got a strange issue. When I print a polygon from PostGIS (v1.3.6)
thanks to the AsText() function I get a different result than if I read
the WKB into a geos (v3.1.0 and v3.1.1) geometry object and than write
it with geos::io::WKTWriter.
When asking PostGIS to check the geometry's
On 07/05/09 10:49, tommy408 wrote:
thank you Mike and Kevin
There is another solution (that I use) to iterate over the points of a
Polygon. Via the ST_ExteriorRing function one can get the LineString of
the exterior ring and therefore use ST_PointN.
--
yabo
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