Re: [postgis-users] ST_MinkowskiSum

2013-12-09 Thread Oliver Courtin
Le 8 déc. 2013 à 05:41, Stephen Mather a écrit : Hi Stephen, but I can't say I quite understand the product it is creating... . Did you have a look on: http://en.wikipedia.org/wiki/Minkowski_addition http://doc.cgal.org/latest/Minkowski_sum_2/index.html And i agree with you, this spatial

Re: [postgis-users] postgis.backend -- how to set?

2013-12-09 Thread Rémi Cura
I had a bug with this so be a little carefull ;-) Cheers, Rémi-C 2013/12/8 Stephen Mather step...@smathermather.com Awesome. Thank you. On Sun, Dec 8, 2013 at 12:53 AM, Bborie Park dustym...@gmail.com wrote: SET postgis.backend = geos; The docs for postgis.gdal_datapath have

[postgis-users] functions

2013-12-09 Thread Jonatan Malaver
Hello, I'm new to postgis/postgresql. I was wondering if anyone could tell me how to make a function out of this sql query: WITH RECURSIVE flow(gid, geom) AS ( SELECT e.gid, e.geom FROM electric_line e, fuses f WHERE ST_DWithin(ST_AsText(e.geom)::geometry, ST_AsText(f.geom)::geometry,

[postgis-users] help with the Union of 2 shp

2013-12-09 Thread J.Alejandro Martinez Linares
Hi People, i need your help, let say that i have 2 shapefiles 1-the first shapefile __ | | | | |1 | shp=B | | | | |_| One big

Re: [postgis-users] ST_Tesselate

2013-12-09 Thread Stephen Mather
Ah, very cool. So hard breaklines plus a point cloud could be fed in creating a DTM... . On Mon, Dec 9, 2013 at 3:26 AM, Oliver Courtin olivier.cour...@oslandia.com wrote: Le 8 déc. 2013 à 00:23, Stephen Mather a écrit : What does ST_Tesselate do? Triangulation, a constrained Delaunay

Re: [postgis-users] ST_Tesselate

2013-12-09 Thread Stephen Mather
From wikipedia: A *tessellation* is the tiling of a planehttps://en.wikipedia.org/wiki/Plane_%28mathematics%29using one or more geometric shapes, called tiles, with no overlaps and no gaps. I'd say a constrained Delaunay applies :D. On Mon, Dec 9, 2013 at 2:24 PM, Martin Feuchtwanger

Re: [postgis-users] postgis.backend -- how to set?

2013-12-09 Thread Stephen Mather
Thanks Remi, I'll proceed cautiously. Best, Steve On Mon, Dec 9, 2013 at 9:59 AM, Rémi Cura remi.c...@gmail.com wrote: I had a bug with this so be a little carefull ;-) Cheers, Rémi-C 2013/12/8 Stephen Mather step...@smathermather.com Awesome. Thank you. On Sun, Dec 8, 2013 at

Re: [postgis-users] ST_MinkowskiSum

2013-12-09 Thread Stephen Mather
I think the tricky part is under certain conditions, it is quite intuitive, but my intuition must be to simple because then there are real surprises... . This is a fun addition though-- although maybe I'll start with the 2D case and give my brain a rest. Best, Steve On Mon, Dec 9, 2013 at

Re: [postgis-users] help with the Union of 2 shp

2013-12-09 Thread J.Alejandro Martinez Linares
El 10/12/13 02:06, Stephen Mather escribió: Hi, Try pg 21 of this: http://presentations.opengeo.org/2011_FOSS4G/postgis-power.pdf That will give you the metacode. thanks for the answer but, i have no internet, i dont understand what do you mean, please Overlays. (he sighs.) Be glad

[postgis-users] Overlapping of polygons with SimplifyPreserveTopology

2013-12-09 Thread Luca Morandini
Folks, we noticed that, despite the use of ST_SimplifyPreserveTopology, non-adjacent polygons may overlap; this happens when there is a long and narrow water body of between them (think of a fiord), but this body is not itself a polygon. To solve this issue we came up with the idea of adding

Re: [postgis-users] functions

2013-12-09 Thread Jonatan Malaver
Thank you!!! Jon From: postgis-users-boun...@lists.osgeo.org [mailto:postgis-users-boun...@lists.osgeo.org] On Behalf Of tommaso Sent: Monday, December 09, 2013 12:57 PM To: PostGIS Users Discussion Subject: Re: [postgis-users] functions This should work: create or replace function

Re: [postgis-users] functions

2013-12-09 Thread Jonatan Malaver
Another question, what can I do to improve performance on the query? The query can take 2 seconds or more. From: postgis-users-boun...@lists.osgeo.org [mailto:postgis-users-boun...@lists.osgeo.org] On Behalf Of Jonatan Malaver Sent: Monday, December 09, 2013 8:52 PM To: PostGIS Users Discussion

Re: [postgis-users] Overlapping of polygons with SimplifyPreserveTopology

2013-12-09 Thread Paolo Cavallini
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Il 10/12/2013 04:49, Luca Morandini ha scritto: we noticed that, despite the use of ST_SimplifyPreserveTopology, non-adjacent polygons may overlap; this happens when there is a long and narrow water body of between them (think of a fiord), but

Re: [postgis-users] Overlapping of polygons withSimplifyPreserveTopology

2013-12-09 Thread Hugues François
Hello, You should also have a look at some functions made by Nicolas Ribot : http://trac.osgeo.org/postgis/wiki/UsersWikiSimplifyPreserveTopology Topology approach is also described. Hugues. -Original Message- From: postgis-users-boun...@lists.osgeo.org

Re: [postgis-users] functions

2013-12-09 Thread tommaso
Why do you do ST_AsText(e.geom)::geometry? This is equivalent to e.geom. Change the query so: SELECT e.gid, e.geom FROM electric_line e, fuses f WHERE ST_DWithin(e.geom, f.geom 0.01) AND f.gid=$1 . No sure if it does help, but you you can also try so: SELECT e.gid, e.geom FROM