Thanks Leo, for the code fragment. Re. storing multiple geometries in one column, I found the following caveat --
[http://lists.refractions.net/pipermail/udig-users/2009-March/000553.html] Briefly, is it possible that programs such as QGIS/uDig, etc. would get confused about which column to draw? Does that concern still apply? On Mar 7, 2011, at 11:50 PM, Paragon Corporation wrote: > Puneet, > > Something like this? This is a bit old. We have some example in our book > using Common Table Expressions (CTEs) in chapter 8. You can download the > code to see those as well. http://www.postgis.us/chapter_08 > > http://www.bostongis.com/postgis_translate.snippet > > As far as storing two geometry columns in one table. Yes -- Just do it by > creating another column that is geometry (or using AddGeometryColumn > function). We do it all the time. > > Leo > http://www.postgis.us > > > > -----Original Message----- > From: postgis-users-boun...@postgis.refractions.net > [mailto:postgis-users-boun...@postgis.refractions.net] On Behalf Of Mr. > Puneet Kishor > Sent: Monday, March 07, 2011 11:13 PM > To: PostGIS Users Discussion > Subject: [postgis-users] Creating a grid purely in SQL > > Given a top-left starting point [ulx, uly], and a cell width 'w' and height > 'h', is it possible to create a table entirely in SQL populated with rows > increasing from left to right up to X and top to bottom up to Y. The table > schema would be something like -- > > CREATE TABLE cells ( > cell_id INTEGER NOT NULL, > xmid DOUBLE PRECISION, > ymid DOUBLE PRECISION, > the_geom GEOMETRY, > CONSTRAINT cells_pkey PRIMARY KEY (cell_id) ); > > where xmid = (xmin + xmax) / 2 and ymid = (ymin + ymax) / 2, [xmin, ymin, > xmax, ymax] being the corners of each cell. > > A bonus question -- is it possible to store two geometry columns in one > table? For example, if I wanted to store the geometry for both the center > points [xmin, ymid] as well as the box [xmin, ymin, xmax, ymax], would that > be possible? Would that even be recommended (for example, to speed up > queries/drawing, etc.). > > Puneet. > _______________________________________________ > 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