[Freegis-list] Re: terrain database, how?

[yxu]

Thanks for the information.  Do you know any existing toolkits for
creating and managing the multi-level detailed terrain data?

Thank you,

yxu 



On Tue, 01 Mar 2005 16:11:16 +0100, Simon Chenery <schenery at cosiro.de> wrote:
> 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.
> 
> 
> 
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