[Freegis-list] terrain database, how?

[Simon Chenery]

Yxu,

 > Am 28. Feb 2005 um 11:38:27 schrieb yxu:
 >
 > > I am working on a terrain visualization software that is capable of
 > > visualizing huge areas. But I have no idea on how to organize the
 > > data. Should I organize the data in conventional way: that is to break
 > > up the whole area into lots of small files,  or to use database
 > > software such as mysql?
 >
 >
 > The general rule on such a problem is to use your own optimisations
 > and not a general purpose database.
 > This is because you know your problem and the constrains best
 > and can design the system (read only, buffering) fully according to
 > your application needs.
 >
 > So I probably would go with breaking the data up in tiles.

As you have a huge terrain raster database then it may be worthwhile
investigating if/how the software can access "pyramid layers".
 
Pyramid layers are lower resolution (1/2, 1/4, 1/8, ...) copies of the 
original
data.  Displaying a lower resolution pyramid layer instead of the original
image will greatly improve display speed when the user zooms out further
and further.

It is common in raster data visualisation applications to combine
image compression, tiling and pyramid layers for best performance.

 >
 >       Bernhard

Simon.