Redbeard wrote:
> 
> I'm looking for a heightfield for the entire US of A, or at least the contiguous
> 48 states.  Right now I appear to have two options.
> 
> I've done several searches and most of the time I get lots of USGS info... these
> are really to high a resolution for my needs.  But I *could* download *all* of
> the DEM files and stitch them together then reduce the resolution (ewww... I
> don't think I've got the HD space or the memory)
> 
> I could also take one of the higher res. whole earth pictures I've found and
> just cut out the US.  But the problem with that is two-fold.  1) too *low*
> resolution.  2) improper projection for a decent rendering of US (although I
> could cut from a mapped spherical isosurface)
> 
> Any suggestions?
> 

If 1 km resolution (which is already quite a lot for the whole US),
available at:

http://edcdaac.usgs.gov/gtopo30/gtopo30.html

is not enough, it is difficult, i think there is no free single data set
for the whole country.  

If you want to pay, there is for example:

http://edcnts12.cr.usgs.gov/ned/

Apart from that i right now only see the possibility of putting things
together manually.  A complete list of maps sorted by state is on:

http://edc.usgs.gov/glis/hyper/guide/1_dgr_demfig/states.html

If disk space is the problem, you can reduce size before putting them
together.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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