gmane.comp.gis.postgis

Re: relationship functions not working well

William Kyngesburye — 2008-12-05T02:50:34

Sounds right, given the way these functions appear to behave. Ack! Pretty complex for what should be a simple, and basic, operation. Maybe I'm trying to make it too complex? Is there a simple way to select all features within a rectangle? There should be, it's a common thing to do. ----- William Kyngesburye http://www.kyngchaos.com/ "We are at war with them. Neither in hatred nor revenge and with no particular pleasure I shall kill every ___ I can until the war is over. That is my duty." "Don't you even hate 'em?" "What good would it do if I did? If all the many millions of people of the allied nations devoted an entire year exclusively to hating the ____ it wouldn't kill one ___ nor shorten the war one day." "And it might give 'em all stomach ulcers." - Tarzan, on war

Re: relationship functions not working well

Martin Davis — 2008-12-05T01:23:46

It sounds like you want the relationship "intersects-and-not-touches" - does that sound right? This relation has quite a complex expression in terms of the IM pattern languge. It is: [T********] or [*T*******] or [***T*****] or [****T****] and not ( [FT*******] or [F**T*****] or [F***T****] ) This is equivalent to: not ([FF*FF****] or [FT*******] or [F**T*****] or [F***T****] ) Unfortunately I don't think there is a "closed-form" or single-string pattern for this which can be used with the boolean relate function. The intersection-matrix-returning version of relate will be needed - but even then testing these patterns is going to be tricky. I've had some thoughts in the past that what is required is a more complete pattern-matching language for relate, so that the above logic could be specified and evaluated. Or, a matches_IM_pattern function could be provided, which would allow evaluation of boolean combinations of patterns against the IM string returned from relate. Another option would

relationship functions not working well

William Kyngesburye — 2008-12-04T18:17:00

When I was debugging my invalid geometry problem, I needed to select a small area to view. The data is divided up into 1 degree tiles (it's the SRTM SWBD shapefiles imported). I figured selecting by whole integer degrees would be simple to deal with. I started with st_overlaps(), as it was mentioned in the wiki I think, or somewhere online (this was a few weeks ago, and don't remember the details). But it was not selecting very much at all in a large area. I looked at the PostGIS documentation to see what other functions would work, but their descriptions are not plain english and and tried them all. And there was a pointer to: http://lin-ear-th-inking.blogspot.com/2007/06/subtleties-of-ogc-covers-spatial.html that helped a little. But none of the ones I tried gave me what I want - polygon areas completely inside the box boundary and area, and not polygons where only the boundary touches the box boundary. Snapshots: http://www.kyngchaos.com/wiki/gallery:gis:temp:index ST_Over

RE: RE: WKT Raster project: call for fundings

Burgholzer,Robert — 2008-12-04T16:36:20

I realize that it would only be a drop in the bucket, but would seeking Google Summer of Code funds be a helpful avenue? Robert W. Burgholzer Surface Water Modeler Office of Water Supply and Planning Virginia Department of Environmental Quality rwburgholzer< at >deq.virginia.gov 804-698-4405 Open Source Modeling Tools: http://sourceforge.net/projects/npsource/ -----Original Message----- From: postgis-users-bounces< at >postgis.refractions.net [mailto:postgis-users-bounces< at >postgis.refractions.net] On Behalf Of Pierre Racine Sent: Thursday, December 04, 2008 10:07 AM To: Sandro Santilli; postgis-devel< at >postgis.refractions.net; postgis-users< at >postgis.refractions.net Subject: [postgis-users] RE: WKT Raster project: call for fundings Hi all, For myself, I will start to work on the project about 15 hours per week in march 2009. At this rhythm, we won't have a beta before winter 2010. This is why help would be welcome. So two programmers would be working on the project if someone can fund Sandro. One full time (Sandro), o

WKT Raster project: call for fundings

Sandro Santilli — 2008-12-04T11:21:28

Hi all, As some of you may know, I've been working the past two years on the GNU Flash Player [1], something I've felt the need for since I've been doing flash maps for a few years w/out a fully free stack supporting the result (playback). Now Gnash is good enough for use when authors are willing to target it, and sponsorship reduced, so I'm back lurking in the GIS field. Doing so, I've found the new WKT-raster thread started by Pierre Racine [2] and tought that's something I might be available to work on, given enough fundings can be found. The first steps in that direction would be: - Define a new RASTER postgresql type. - Implement canonical input and output SQL routines. - Implement an importer producing a table of RASTER tiles from a single raster file. - Implement an SQL aggregate to return a jpeg from a set. - Overlap operator and simple inspectors (bounds, pixels, bands, sizes). I'm working with Pierre to further refine those steps, but you get the idea. It would take about 6 months

Re: relationship functions not working well

William Kyngesburye — 2008-12-04T21:25:23

There's only 1 table. Is Qgis, I added a where clause to the connection: where ST_Intersects(wkb_geometry, SetSRID('BOX3D(-162 55,-161 56)'::box3d,4326)) Qgis takes care of the rest of the details, but it probably comes out as something like: select * from swbd where ST_Intersects(wkb_geometry, SetSRID('BOX3D(-162 55,-161 56)'::box3d,4326)); ----- William Kyngesburye http://www.kyngchaos.com/ "Oh, look, I seem to have fallen down a deep, dark hole. Now what does that remind me of? Ah, yes - life." - Marvin

Re: problems cleaning geometry - other options?

William Kyngesburye — 2008-12-04T18:46:52

I wonder if there is a way for a postgres function to see what the actual kind of validity error is (it just comes up as a NOTICE: in the sql output)? I ran thru the whole database to see how many invalid polys there are (10700 of 625000) and what they are (and how long it will take just to test validity... 5m, not bad), and I see more than just this one case I first ran into (hole outside shell): NOTICE: Hole lies outside shell at or near point x y [not many of these] NOTICE: Nested shells at or near point x y [lots of these] NOTICE: Holes are nested at or near point x y [lots of these] NOTICE: Self-intersection at or near point x y NOTICE: Ring Self-intersection at or near point x y NOTICE: Interior is disconnected at or near point x y [a few of these] It would be nice if the cleangeometry function could use the right combination of geometry operations depending on the type of geometry error. ----- William Kyngesburye http://www.kyngchaos.co

Re: problems cleaning geometry - other options?

Kevin Neufeld — 2008-12-04T07:02:02

Have you tried updating the geometry with a new polygonized polygon constructed from the linework? UPDATE swbd SET wkb_geometry = ST_BuildArea(ST_Boundary(wkb_geometry)) WHERE cell = 145018 AND wb = 353; Cheers,

Re: relationship functions not working well

Nicolas Ribot — 2008-12-04T20:11:19

Hi William, Did you try st_relate() the the appropriate DE-9IM matrix ? I can't give you the pattern that will express your need exactly as I read your email rapidely, but looking here may surely help: http://postgis.refractions.net/documentation/manual-svn/ST_Relate.html (also following the intersectionPatternMatrix link) This presentation may also help: http://www.foss4g2007.org/presentations/view.php?abstract_id=117 Nicolas

Re: relationship functions not working well

William Kyngesburye — 2008-12-04T20:57:11

I was wondering about that function. Unfortunately postgis 1.3 documentation doesn't have that handy link about the intersectionPatternMatrix that's in the svn documentation. I'll look at that, thanks. ----- William Kyngesburye http://www.kyngchaos.com/ "Oh, look, I seem to have fallen down a deep, dark hole. Now what does that remind me of? Ah, yes - life." - Marvin

Re: problems cleaning geometry - other options?

William Kyngesburye — 2008-12-04T14:56:19

That works. It looks essentially the same as what's in the cleangeometry function from the wiki, but much simpler. There's st_union and st_multi in there betwen the buildarea and boundary functions, probably to handle other invalid stuff. On Dec 4, 2008, at 1:02 AM, Kevin Neufeld wrote: ----- William Kyngesburye http://www.kyngchaos.com/ First Pogril: Why is life like sticking your head in a bucket filled with hyena offal? Second Pogril: I don't know. Why IS life like sticking your head in a bucket filled with hyena offal? First Pogril: I don't know either. Wretched, isn't it? -HitchHiker's Guide to the Galaxy

Re: relationship functions not working well

Dylan Beaudette — 2008-12-04T21:07:57

Can you show us your queries? Some of these examples look a little funny -- i.e. did you query contain the ST_xxx() function in the JOIN condition and the gometry construction?

Re: problems cleaning geometry - other options?

Kevin Neufeld — 2008-12-04T20:33:12

Yes, very new and still in discussion amongst the development team, but it's possible to do this with the development branch (svn head) of PostGIS. postgis=# SELECT ST_IsValidReason( 'POLYGON (( 0 0, 0 4, 4 4, 4 0, 0 0 ), ( 3 5, 2 5, 2 6, 3 6, 3 5 ))'::geometry); st_isvalidreason ------------------------------- Hole lies outside shell [3 5] (1 row) test=# SELECT ST_IsValidReason( 'POLYGON (( 0 0, 0 4, 4 4, 4 0, 0 0 ), ( 2 2, 2 3, 3 3, 5 2, 2 2 ))'::geometry); st_isvalidreason --------------------------- Self-intersection [4 2.5] (1 row) Cheers, Kevin

NAD conversion problem

Peter N. Schweitzer — 2008-12-04T20:19:22

Hello, I have two PostgreSQL installations. One uses 8.3.3 with PostGIS 1.3.3, GEOS 3.0.1, and PROJ 4.6.1 (with proj-datumgrid-1.4). With it I am able to run a command like update county set nad27_geom=ST_Transform(the_geom,4267); My newer installation uses 8.3.5 with PostGIS 1.3.4, GEOS 3.0.3, and PROJ 4.6.1. With this system I get the error message WARNING: transform: -38 (failed to load NAD27-83 correction file) ERROR: transform: couldn't project point: -38 (failed to load NAD27-83 correction file) I know that proj-datumgrid-1.4.zip must be unzipped in the nad/ directory of proj-4.6.1 PRIOR to running configure. I have done this. I have also recompiled and reinstalled proj, GEOS, and PostGIS in that order, running ldconfig at the end of each step. The directory /usr/local/share/proj on each of these systems is identical. I've tried recreating the database cluster, starting and stopping the database instance, rebooting the machine, dropping and rebuilding the spatial database, all to no avai

Re: problems cleaning geometry - other options?

Kevin Neufeld — 2008-12-04T16:53:08

Correct. I assumed in your case that the rings do not need to be noded against eachother (that's what st_union is for), they just need to be sorted to determine the outer and inner rings (that's a task for BuildArea). Glad it works.

RE: WKT Raster project: call for fundings

Pierre Racine — 2008-12-04T15:07:15

Hi all, For myself, I will start to work on the project about 15 hours per week in march 2009. At this rhythm, we won't have a beta before winter 2010. This is why help would be welcome. So two programmers would be working on the project if someone can fund Sandro. One full time (Sandro), one half time (me). For now Sandro has very few money and I'll have few time. The main idea of WKT Raster is to treat raster tiles as much as possible like PostGIS geometries so we could query and analyse (intersection, overlay, interpolation, conversion, etc...) vectors and rasters seamlessly. WKT Raster is much simpler than Oracle Georaster and much more GIS oriented (like PostGIS is). A PowerPoint of the design is available at http://www.cef-cfr.ca/uploads/Membres/WKTRasterPostGIS.ppt Pierre

Re: problems cleaning geometry - other options?

Mark Cave-Ayland — 2008-12-04T10:44:17

Hi William, Which versions of PostgreSQL/PostGIS is this? Since the error message in question is only in the lwcurve curve, it sounds like an internal error. If you can extract a standalone test case and post it on the bug tracker, I'll take a look at it. ATB, Mark.

problems cleaning geometry - other options?

William Kyngesburye — 2008-12-04T00:08:45

I'm trying to fix some polygons-with-holes imported from shapefiles where the main polygon is not the first in the list, one of the hole polygons is, making them invalid. These are 3D multipolygons - imported from the SRTM SWBD shapefiles (with GDAL). (file w162n55n if anyone wants to try) The cleanGeometry funtion at: http://postgis.refractions.net/support/wiki/index.php?CleanPolygons isn't working, I get an error: =>select astext(cleangeometry(wkb_geometry)) from swbd where cell = 145018 and wb = 353; NOTICE: Hole lies outside shell at or near point -161.201 55.9992 0 CONTEXT: PL/pgSQL function "cleangeometry" line 15 at IF ERROR: Dimensions mismatch in lwcurve CONTEXT: PL/pgSQL function "cleangeometry" line 19 at assignment I tried forcing the geometry to 2D (st_force_2d()) and I get a different error: NOTICE: Hole lies outside shell at or near point -161.201 55.9992 CONTEXT: PL/pgSQL function "cleangeometry" line 15 at IF ERROR: Exception in LWGEOM2GEOS: curved geometry not suppor

Re: Re: Problem with MultiLineString

2008-12-03T23:38:23

- The reason is documented. The overhead for validating all geometries as entered is generally unecessary. For cases where it is appropriate, an insert trigger using isvalid() can be used to provide this capability. Cheers, BRnet Wood

Re: Problem with MultiLineString

Ken Southerland — 2008-12-03T21:17:52

Thank you! That's got to be it. I knew I just needed a third eye, didn't even see that. A followup question might be why is this geometry allowed to be created if it is then considered invalid by certain functions? Ken Michael Smedberg said: >It looks to me like maybe > >(491215.9577 532660.8051,491215.9577 532660.8051) > >is an invalid line because both points are identical, while > >(491215.957 532660.8051,491215.9577 532660.8051) > >is valid because the points aren't identical? Just a guess...

RE: Problem with MultiLineString

Michael Smedberg — 2008-12-03T20:46:31

It looks to me like maybe (491215.9577 532660.8051,491215.9577 532660.8051) is an invalid line because both points are identical, while (491215.957 532660.8051,491215.9577 532660.8051) is valid because the points aren't identical? Just a guess... -----Original Message----- From: postgis-users-bounces< at >postgis.refractions.net [mailto:postgis-users-bounces< at >postgis.refractions.net] On Behalf Of Ken Southerland Sent: Wednesday, December 03, 2008 12:22 PM To: postgis-users< at >postgis.refractions.net Subject: [postgis-users] Problem with MultiLineString This problem occurs on versions... POSTGIS="1.3.1" GEOS="3.0.0rc4-CAPI-1.3.3" PROJ="Rel. 4.5.0, 22 Oct 2006" POSTGIS="1.3.2" GEOS="3.0.0-CAPI-1.4.1" PROJ="Rel. 4.6.0, 21 Dec 2007" The first query gives... select st_isvalid( st_GeomFromText('MULTILINESTRING((491181.9816 532686.6037,491209.6059 532664.6521),(491215.9577 532660.8051,491215.9577 532660.8051))')); NOTICE: IllegalArgumentException: Number of points must be 0 or >3 st_isvalid ------------ f