Maybe ST_X, ST_Y and ST_Z ? Hugues. ________________________________
De : postgis-users-boun...@postgis.refractions.net [mailto:postgis-users-boun...@postgis.refractions.net] De la part de Ed Linde Envoyé : mardi 30 octobre 2012 11:14 À : PostGIS Users Discussion Objet : Re: [postgis-users] Problem with 3D polygon intersection test Hi Nicolas, Not quite sure what to make of the output from ST_DumpPoints, how do I transform it to just raw x,y,z coordinates? select st_astext(geomtext) from small_tris where id=0; st_astext ------------------------------------------------------- POLYGON Z ((10 10 805,20 10 809,10 20 814,10 10 805)) (1 row) bounds=# select id, st_dumpPoints( geomtext ) from small_tris where id=0; id | st_dumppoints ----+---------------------------------------------------------------------- 0 | ("{1,1}",0101000080000000000000244000000000000024400000000000288940) 0 | ("{1,2}",0101000080000000000000344000000000000024400000000000488940) 0 | ("{1,3}",0101000080000000000000244000000000000034400000000000708940) 0 | ("{1,4}",0101000080000000000000244000000000000024400000000000288940) (4 rows) Thanks,Ed On Tue, Oct 30, 2012 at 11:05 AM, Ed Linde <edoli...@gmail.com> wrote: Ok thanks! On Tue, Oct 30, 2012 at 11:04 AM, Nicolas Ribot <nicolas.ri...@gmail.com> wrote: st_dumpRings will return the rings (closed linestrings) composing the polygon (exterior first, then interiors) and st_dumpPoints will return all the points forming the rings, in the right order. Nicolas On 30 October 2012 10:56, Ed Linde <edoli...@gmail.com> wrote: Ok, for a polygon, is there a good postgis function that can return the edges to me in the right sequence? Or at least the points that constitute the polygon in the right order, so I can generate the edges in a script? Thanks, Ed On Tue, Oct 30, 2012 at 10:46 AM, Ed Linde <edoli...@gmail.com> wrote: Ah drat! Ok then I have to basically do edge intersection tests by myself. Ah well. bad news! :( On Tue, Oct 30, 2012 at 10:44 AM, Nicolas Ribot <nicolas.ri...@gmail.com> wrote: Hi, st_intersection is only suitable for 2D operations. Third dimension is not taken into account. Nicolas On 30 October 2012 09:44, Ed Linde <edoli...@gmail.com> wrote: Hi All, Is there a simpler test I can do? I am quite sure that I am probably not using the right function in my SQL, or not doing the intersection test correctly. Is there any simpler way to test this 3D intersection? Am waiting on the postgis gurus to come along and give me some ideas, coz I am at my wits ends on this one! :) The polygons look good to me when I visualize them, but don't get how all triangles are found as intersecting? Anyway will wait. Cheers, Ed On Tue, Oct 30, 2012 at 9:00 AM, Ed Linde <edoli...@gmail.com> wrote: Hi All, I am having some troubles getting the ST_Intersect function to work with 3D polygons. I have a table to hold triangles as polygons in "small_tris" Another table for holding the polygonal faces of a 3D voronoi diagram in "vfaces" So now I am trying to do an intersection between the triangles and the voronoi faces to get the triangles that intersect with the faces. And it seems that *ALL* triangles are intersecting. I have attached a PDF where I have plotted the triangles and the voronoi cells. so the box around in red and blue with a major face going through is the voronoi diagram. The Voronoi partition in 3D is shown at the bottom too for clarity Can someone please help and let me know what am I doing wrong here? Is the select assuming something? So the polygons are flat and the intersections should just be lines or points. I am under some pressure to get this to work, so if anyone needs more information to help, the please let me know! :) Cheers, Ed -- TABLE SCHEMAS bounds=# \d vfaces; Table "public.vfaces" Column | Type | Modifiers ----------+----------+----------- gen_id | integer | geomtext | geometry | bounds=# \d small_tris; Table "public.small_tris" Column | Type | Modifiers ----------+----------+----------- id | integer | not null v0 | integer | v1 | integer | v2 | integer | geomtext | geometry | Indexes: "small_tris_pkey" PRIMARY KEY, btree (id) "small_idx" gist (geomtext) -- TABLE CONTENT bounds=# select id, st_astext( geomtext ) from small_tris; id | st_astext ----+------------------------------------------------------- 0 | POLYGON Z ((10 10 805,20 10 809,10 20 814,10 10 805)) 1 | POLYGON Z ((10 20 814,20 10 809,20 20 819,10 20 814)) 2 | POLYGON Z ((20 20 819,30 10 809,30 20 812,20 20 819)) 3 | POLYGON Z ((30 10 809,20 20 819,20 10 809,30 10 809)) 4 | POLYGON Z ((30 20 812,30 10 809,40 10 826,30 20 812)) 5 | POLYGON Z ((20 20 819,30 20 812,20 30 827,20 20 819)) 6 | POLYGON Z ((10 20 814,20 20 819,20 30 827,10 20 814)) 7 | POLYGON Z ((10 40 805,10 30 814,20 30 827,10 40 805)) 8 | POLYGON Z ((10 50 804,10 40 805,20 40 807,10 50 804)) 9 | POLYGON Z ((20 30 827,20 40 807,10 40 805,20 30 827)) 10 | POLYGON Z ((30 30 817,20 40 807,20 30 827,30 30 817)) 11 | POLYGON Z ((30 40 816,20 50 809,20 40 807,30 40 816)) 12 | POLYGON Z ((20 40 807,20 50 809,10 50 804,20 40 807)) 13 | POLYGON Z ((10 30 814,10 20 814,20 30 827,10 30 814)) 14 | POLYGON Z ((30 30 817,20 30 827,30 20 812,30 30 817)) 15 | POLYGON Z ((30 20 812,40 20 823,30 30 817,30 20 812)) 16 | POLYGON Z ((40 20 823,30 20 812,40 10 826,40 20 823)) 17 | POLYGON Z ((40 20 823,40 10 826,50 10 803,40 20 823)) 18 | POLYGON Z ((30 30 817,40 20 823,40 30 814,30 30 817)) 19 | POLYGON Z ((40 20 823,50 20 808,40 30 814,40 20 823)) 20 | POLYGON Z ((50 20 808,40 20 823,50 10 803,50 20 808)) 21 | POLYGON Z ((40 30 814,50 20 808,50 30 816,40 30 814)) 22 | POLYGON Z ((30 30 817,40 30 814,40 40 800,30 30 817)) 23 | POLYGON Z ((30 40 816,40 40 800,30 50 813,30 40 816)) 24 | POLYGON Z ((30 40 816,30 30 817,40 40 800,30 40 816)) 25 | POLYGON Z ((30 50 813,40 40 800,40 50 817,30 50 813)) 26 | POLYGON Z ((30 40 816,30 50 813,20 50 809,30 40 816)) 27 | POLYGON Z ((50 40 821,40 50 817,40 40 800,50 40 821)) 28 | POLYGON Z ((50 50 809,40 50 817,50 40 821,50 50 809)) 29 | POLYGON Z ((50 40 821,40 40 800,50 30 816,50 40 821)) 30 | POLYGON Z ((40 30 814,50 30 816,40 40 800,40 30 814)) 31 | POLYGON Z ((30 30 817,30 40 816,20 40 807,30 30 817)) (32 rows) select st_astext(geomtext) from vfaces; st_astext ----------------------------------------------------------------------------------------------- POLYGON Z ((51 17.8 799,9 38.8 799,9 51 819.33333333333,19.4 51 828,51 35.2 828,51 17.8 799)) POLYGON Z ((51 17.8 799,9 38.8 799,9 51 799,51 51 799,51 17.8 799)) POLYGON Z ((51 35.2 828,19.4 51 828,51 51 828,51 35.2 828)) POLYGON Z ((9 9 799,9 38.8 799,51 17.8 799,51 9 799,9 9 799)) POLYGON Z ((51 17.8 799,9 38.8 799,9 51 819.33333333333,19.4 51 828,51 35.2 828,51 17.8 799)) POLYGON Z ((9 9 828,9 51 828,19.4 51 828,51 35.2 828,51 9 828,9 9 828)) (6 rows) select distinct a.id from small_tris a, vfaces b where st_intersects (a.geomtext, b.geomtext) order by a.id; id ---- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 (32 rows) _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
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