On 10/29/2009 8:28 AM, clipka wrote:
> With 16 bit depth, however, you can represent...
>
> ... the entire earth's topology (including ocean floors) to a vertical
> resolution of ca. 30 cm, or 1'0".
>
> ... the entire earth's continental topology (i.e. above ocean level) to
> a vertical resolition of about 15 cm, or 6".
>
> ... a section of the Grand Canyon to a vertical resolution of about 2,5
> cm, or 1".

Artifacts would be noticable if, say, your were rendering an image of a 
lizard with the Grand Canyon visible in the background. But, you're 
right, that level of precision wouldn't make much of a difference in the 
majority of heightfields. It *would* make a difference if you wanted 
smooth transitions between scales on a spherical, isosurface model of 
the Earth. But isosurfaces aren't based on bitmap data...

Mike

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> Artifacts would be noticable if, say, your were rendering an image of a 
> lizard with the Grand Canyon visible in the background.

Man, you'd need some kind of supercomputer to model the entire grand canyon 
in enough detail to do a close-up of a lizard on it...

Use some kind of level of detail scheme (ie further away parts are modelled 
at lower resolution) - then you'll find that 16 bits of vertical resolution 
is plenty for the scene you mention.

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