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For dry land, we recognize
two basic types
of
DEM:
Digital Terrain Models (DTMs) describing
"bare-earth" terrain, and Digital Surface Models (DSMs)
describing "full-featured" surfaces that include
vegetation and infrastructural features.
We also understand the benefits of applying a similar
treatment to sub-marine
bathymetric DEMs.
We are experienced with ...
- format conversion,
- horizontal and vertical datum
adjustment,
- interpolation applied to
...
- resolution reduction, no-data-hole filling,
feature removal, contour generation,
- cartography, and
3D Geo-animation,
from the following data sources
...
- GTOPO30,
Global Topography with 30 arc second ( ~1,000 m)
DTM with a vertical accuracy of LE90 = 30 m. Archive
coverage is Global.
- SRTM,
(Shuttle Radar Topography
Mission) 3 arc second (~ 93
m) DTM with a vertical accuracy of LE90 = 16 m. Archive
coverage is Global.
- Stereo Satellite Imagery, DTM
and DSM options with spatial resolution ranging from 3 m to 30 m
and vertical accuracy ranging from LE90 = 3 m to 10 m.
Global archive coverage from ASTER only,
DEMs derived from all other systems may likely require special tasking.
-
NED,
(National Elevation Dataset):
1 arc second (10 m) DTM with an overall vertical accuracy of LE90
= 5 m. Archive coverage includes all US territories.
- Lidar,
(Light Detection and
Ranging): DTM and DSM
options with sub-meter spatial resolution and vertical accuracy
down to LE90 = 15 cm. Limited commercial and public
archives. Project tasking likely.
- Sonar, (Sound
Navigation and Ranging): we are developing a multi-modal
bathymetric surveying and post processing system for surveys
down to 80 meters below sea level.
Click here for a
definition of LE90.
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