[Tiling] compact tile format anyone

[Mateusz Loskot]

On 23/12/10 10:43, Oliver Tonnhofer wrote:
> If we go the single file SQL DB route but we can't agree on a
> specific file format, we still could design a SQL schema
> specification. That way it would be easy to convert between
> different implementations (e.g. from H2 to SQLite).

There is SpatiaLite which is a PostGIS for SQLite.
If we assume PostGIS as a reference implementation for vectors in
database, perhaps we could consider it as an exemplar for raster
data too. Here we go:

http://trac.osgeo.org/postgis/wiki/WKTRaster

This initiative is mature in terms of its specification and,
I'm not afraid to say that, in implementation too.
I'd say it's ready for use in production.
It integrates very well with the PostGIS GEOMETRY type.
It supports overviews and various configurations of raster.
It is open for further improvements and development.
It is not only about storage, but also about raster processing
(see ST_MapAlgebra function).
It has a huge potential.

I'd suggest to take a look at specification of the PostGIS RASTER
(formerly known as WKTRaster) and see if it would fit the ideas and
needs discussed here. If something is missing, I believe the spec can be
improved and PostGIS will benefit as well.
Once the spec is made "portable", it's a matter of implementing it for
SQLite (perhaps with collaboration of SpatiaLite).

There is RasterLite, brother (or sister) of SpatiaLite, but IMHO its
data model doesn't scale well for large number of use cases.

> PS: We have a student that we like to sponsor to do some research in
> that direction in his bachelor theses, but that would start not
> until next summer.

I've started praying for the Community here to find the WKTRaster
interesting :-)

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
Member of ACCU, http://accu.org