I think uDig still has that problem last we checked, but I don't think QGIS does. QGIS lets you pick the column.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Mr. Puneet Kishor Sent: Monday, March 07, 2011 11:54 PM To: PostGIS Users Discussion Subject: Re: [postgis-users] Creating a grid purely in SQL 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: [email protected] > [mailto:[email protected]] 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 > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
