Hello everyone,

I am working on a weather application and I've been looking over the
internet for topographic image of the entire US but to no avail. I am
posting here to see if I can get some help from the GIF experts out
there to get what I want...

    * Topographic image of the entire United States
    * Format: DEM or BIL
    * Filesize should not exceed 200 MB (the smaller the better)

The closest I have found:
http://www.weather.gov/geodata/catalog/topo/html/ustopo.htm

This map is 80% of the way there, however, it is not high enough
resolution at "30 arcsec". I am assuming 15 or 10 "arcsec" would be
exactly what I need.

I know there are many websites which have extremely high resolution
data, but we can only download one state at a time. I want the entire
United States or at least the mainland USA in one file.

Any recommendation will be much appreciated.

Thanks!
Elizabeth

ebethys@gmail.com writes:
> The closest I have found:
> http://www.weather.gov/geodata/catalog/topo/html/ustopo.htm
>
> This map is 80% of the way there, however, it is not high enough
> resolution at "30 arcsec". I am assuming 15 or 10 "arcsec" would be
> exactly what I need.

That page says their image was "derived from National Geophysical Data
Center (NGDC) DTM [30 arcsec]" which makes it sound quite possible the
source data was higher resolution.

I see the source data seem to be here (in various forms):

    http://www.ngdc.noaa.gov/mgg/topo/globeget.html

and the file sizes seem bigger, so perhaps it is higher resolution.

-Miles

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Religion, n. A daughter of Hope and Fear, explaining to Ignorance the nature
of the Unknowable.