[postgis-users] Rasters - world wide SRTM dataset for altitude profile?

[Frederik Ramm]

Hi,

    forgive me for barging in with little background knowledge. I'm a 
regular PostGIS user but haven't used rasters with PostGIS yet, and I 
was hoping that you could give me a quick "reality check" on the 
following idea.

In OpenStreetMap we sometimes have the requirement to generate altitude 
profiles for a route. There's a 4-year-old summer of code project that 
imports SRTM data into Postgres, by creating a two-column table of 
quadtile location code (bigint) and altitude (int), and then 
step-by-step assembling height values for a given route geometry.

Importing SRTM data into that structure takes quite long and needs a lot 
of storage space.

I wonder if, with PostGIS raster support, I could:

* simply import a world-wide SRTM data set (I'm sure people must have 
done that already?)
* and then efficiently query the nearest raster values for a given 
linestring geometry, thereby getting an altitude profile?

Without having checked the limits of PostGIS raster support, it sounds 
to me as if this could be much simpler than the old approach. Can you 
see any obvious problems with that idea, or should I go ahead and try it?

Bye
Frederik