All tiles of a same coverage should be stored in the same table. One tile per row.
There is a variant of ST_SummaryStats working on such a table as a whole. You have to pass the name of the table and the name of the raster column. Pierre > -----Original Message----- > From: [email protected] [mailto:postgis-users- > [email protected]] On Behalf Of Joan > Sent: Tuesday, November 08, 2011 12:14 PM > To: PostGIS Users Discussion > Subject: Re: [postgis-users] Tiles > > In a case where I use ST_SummaryStats I would like to have statistics of the > coverage, so I should have the coverage as one tile. Isn't it inconvenient > for a > user to have several tables of the same coverage? > > > On 8 November 2011 18:01, Pierre Racine <[email protected]> wrote: > > > Briefly the ST_Intersection(rast, geom) vectorize the raster in order > to > make a standard vector/vector intersection afterward. Since vectorizing is a > slow process, a query involving ST_Intersection() is always more efficient > with > smaller tiles. > > Pierre > > > > -----Original Message----- > > From: [email protected] [mailto:postgis- > users- > > [email protected]] On Behalf Of Joan > > > Sent: Tuesday, November 08, 2011 11 <tel:2011%2011> :56 AM > > To: PostGIS Users Discussion > > Subject: Re: [postgis-users] Tiles > > > > > Yes, I have been doing an analysis with the same raster file but > different tile sizes > > and I get different results e.g st_intersects(rast, geom) . I would > like to > know > > what the tile size has to do with the query results or performance. > > > > > > > > > On 8 November 2011 17 <tel:2011%2017> <tel:2011%2017> :30, > Pierre Racine > > > <[email protected]> wrote: > > > > > > I guess you mean "raster tile"? > > > > > -----Original Message----- > > > From: [email protected] > [mailto:postgis- > > users- > > > [email protected]] On Behalf Of Joan > > > > Sent: Tuesday, November 08, 2011 10 <tel:2011%2010> > <tel:2011%2010> :19 AM > > > > To: PostGIS Users Discussion > > > Subject: [postgis-users] Tiles > > > > > > > > Hello, > > > > > > I would like to know what the idea behind tiles is. > > > > > > Regards > > > > > > Joan M > > > > _______________________________________________ > > 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
