[postgis-users] merging geometries of buffer on large data set

I was wondering if there is a good (or best practice) approach on how to merge geometry features that are touching or overlapping and have one common value in one table field. Here is what I was trying to do: given a large dataset such as the (detailed NHD data layer) of rivers in California I

Re: [postgis-users] PostGIS Raster ST_Value ST_SetValue performance (Bborie Park)

Dear, Thank you for your answers. I think that Bborie option is the best for me. I must wait for next postgis version. Regards, -- MIGUEL ANGEL MANSO CALLEJO Universidad Politecnica de Madrid ___ postgis-users mailing list postgis-users@lists.osgeo

Re: [postgis-users] [OT] How to construct and float8[][] array?

Hi Steve, did you try execute the most nested subquery and the upper one to see which one causes the ERROR? There is also an array_cat function that support multidimensional arrays. http://www.postgresql.org/docs/9.1/static/arrays.html best regards, Humberto Cereser Ibanez Em Sex, 2013-06-28

[postgis-users] [OT] How to construct and float8[][] array?

Hi all, This is a little bit off topic but I'm trying to create a nxn array like the following in SQL: {{0,1,2,3},{1,0,3,2},{2,3,0,4},{3,2,4,0}} select array_ndims('{{0,1,2,3},{1,0,3,2},{2,3,0,4},{3,2,4,0}}'::float[][]); -- 2 select array_dims('{{0,1,2,3},{1,0,3,2},{2,3,0,4},{3,2,4,0}}'::flo

[postgis-users] Cleaning up a text import

Hi I imported some text using the Quantum GIS dxf2postgiswhich somehow became distorted through the import. What should have been imported was TK-208. What I got was %%UTK-208%%U. Perhaps I did something wrong while using dxf2postgis? Otherwise, I can trim the text using - select trim (both

Re: [postgis-users] PostGIS Raster ST_Value ST_SetValue performance

Hey Miguel, If you're on PostGIS 2.0, there aren't faster alternatives for ST_SetValue() and ST_Value(). PostGIS 2.1 (hopefully released in the next several weeks) brings ST_SetValues() and ST_DumpValues(). As for your specific implementation, You could consider the use of ST_MapAlgebraFct() wher

Re: [postgis-users] st_difference results

ups forget the ss Em 28-06-2013 13:20, Pedro Costa escreveu: Hi people, I'm trying to make an st_difference with polygons and lines. But the result is a thousand of features because i get the difference between each polygon on the left side and ALL of the linestrings on the right. I want o

[postgis-users] st_difference results

Hi people, I'm trying to make an st_difference with polygons and lines. But the result is a thousand of features because i get the difference between each polygon on the left side and ALL of the linestrings on the right. I want only simple linestrings (not multi) that don't intersect the po

Re: [postgis-users] PostGIS Raster ST_Value ST_SetValue performance

Hello, I'm not sure to understand the problem, but I'll give a try. You can try to reproduce Oracle's steps and make a plpg function that 1. first create a new table, or a multidimentionnal array, where you can store columnx, rowy (this can be done since you know the origin and cell size, cal

[postgis-users] PostGIS Raster ST_Value ST_SetValue performance

Good morning, It's my first comment to the email-list. I'm developing a PLSQL-procedure that generate a raster band counting points of a geometry table/layer that are included in a cell. This can be seen as a simple clustering algorithm. To do it, i'm using a cursor and determining the row a