[postgis-users] Tiles

[Joan]

Oh, I will try that out. Thank you.

Joan

On 8 November 2011 18:16, Pierre Racine <Pierre.Racine at sbf.ulaval.ca> wrote:

> 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: postgis-users-bounces at postgis.refractions.net [mailto:
> postgis-users-
> > bounces at postgis.refractions.net] 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 <Pierre.Racine at sbf.ulaval.ca>
> 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: postgis-users-bounces at postgis.refractions.net [mailto:
> postgis-
> > users-
> >       > bounces at postgis.refractions.net] 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
> >
> >       > <Pierre.Racine at sbf.ulaval.ca> wrote:
> >       >
> >       >
> >       >       I guess you mean "raster tile"?
> >       >
> >       >       > -----Original Message-----
> >       >       > From: postgis-users-bounces at postgis.refractions.net
> > [mailto:postgis-
> >       > users-
> >       >       > bounces at postgis.refractions.net] 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
> >       >
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> >       >
> >       >
> >
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> >
>
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