On 3/4/12 12:44 AM, Mark Robinson wrote:
> What is SRTM . DEMS and DTED
SRTM - Shuttle Radar Topographic Mission - THey built a precision
interferometric Synthetic Aperture Radar that mounted in the shuttle's
cargo bay and had a 60m(?) boom sticking out, with precision metrology,
to hold a second antenna.
They basically mapped most of the earth's non-polar area surface at an
accuracy finer than 10meters horizontal resolution, 1 meter vertical
resolution. Quite an achievement in many ways. (the proverbial
truckload of data tapes were brought back down, and they spent several
years processing them)
DTED - Digital Terrain Elevation Data - gridded elevation data at a
specified precision and resolution
DEM - Digital Elevation Model - essentially the same thing, gridded
elevation data Historically, USGS produced DEMs and DoD produced DTEDs.
The grids are either "fixed distance between posts" (e.g. 30meters) or
"fixed angle between posts" (e.g. 1 arc second of lat/lon).
>
>
> Mark N1UK
>
>
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