[postgis-users] selected aligned tiles in pgraster between several large raster tables.

[Graeme B. Bell]

> Have you considered storing your rasters outside the database with
> raster2pgsql's -R flag? I usually recommend this if the rasters are
> readonly. This also minimizes the amount of information stored within
> the database to just the metadata of the out-db rasters.
> 
> -bborie

Hi bborie,

Thanks very much for your reply, but unfortunately I feel in-DB vs out-DB is orthogonal to the issue I'm talking about. 

It makes no real difference here whether the rasters are stored in-DB or out-of-DB from the point of view of the SQL interface. 

The question I'm asking is about how you can best use an SQL and PostGIS interface to perform comparisons or calculations using *equivalent tiles* of *logically distinct rasters* through PostGIS - without resorting to lumping them together as bands in a single raster. 

Graeme.