Hi Puneet, I used Python to create a list of centroid coordinates based on the specified size of each cell, then i used the ST_Envelope to create the walls of each grid cell. Like this: UPDATE priogrid SET cell=geometry(ST_MakeEnvelope(xcoord-"+str(xhalf)+", ycoord-"+str(yhalf)+", xcoord+"+str(xhalf)+", ycoord+"+str(yhalf)+", 4326));
2011/3/8 Paragon Corporation <l...@pcorp.us> > 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: postgis-users-boun...@postgis.refractions.net > [mailto:postgis-users-boun...@postgis.refractions.net] On Behalf Of Mr. > Puneet Kishor > Sent: Monday, March 07, 2011 11:54 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: 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 > > > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users >
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