NASADEM Slope and Curvature Global 1 arc second

PI: Sean Buckley


The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) Digital Elevation Model (DEM) version 1 (NASADEM_SC) dataset, which provides global slope and curvature elevation data at 1 arc second spacing.

NASADEM data products were derived from original telemetry data from the Shuttle Radar Topography Mission (SRTM), a collaboration between NASA and the National Geospatial-Intelligence Agency (NGA), as well as participation from the German and Italian space agencies. SRTM’s primary focus was to generate a near-global DEM of the Earth using radar interferometry. It was a primary component of the payload on space shuttle Endeavour during its STS-99 mission, which was launched on February 11, 2000, and flew for 11 days.

In addition to Terra Advanced Spaceborne Thermal and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) Version 2 data, NASADEM also relied on Ice, Cloud, and Land Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS) ground control points of its lidar shots to improve surface elevation measurements that led to improved geolocation accuracy. Other reprocessing improvements include the conversion to geoid reference and the use of GDEMs and Advanced Land Observing Satellite Panchromatic Remote-sensing instrument for Stereo Mapping (PRISM) AW3D30 DEM, and interpolation for void filling.

NASADEM are distributed in 1 degree latitude by 1 degree longitude tiles and consist of all land between 60° N and 56° S latitude. This accounts for about 80% of Earth’s total landmass.

NASADEM_SC data product layers include slope, aspect angle, profile curvature, plan curvature, and an updated SRTM water body dataset (water mask). A low-resolution browse image showing slope is also available for each NASADEM_SC granule.

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Collection and Granule


Characteristic Description
File Size~164.6 MB
Temporal ResolutionMulti-Day
Temporal Extent2000-02-11 to 2000-02-21
Spatial ExtentGlobal (60°N to 56°S, 180°W to 180°E)
Coordinate SystemGeographic Latitude and Longitude
File FormatRAW
Geographic Dimensions1 degree lat x 1 degree lon


Characteristic Description
Number of Science Dataset (SDS) Layers5
Columns/Rows3601 x 3601
Pixel Size~30 m

Layers / Variables

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
SLOPE Slope derived from merged hgt Degree 16-bit unsigned integer 0 NaN Non-negative 0.01
ASPECT Slope aspect angle derived from merged hgt Degree 16-bit unsigned integer 0 NaN Non-negative 0.01
PLAN (PLANC)¹ Plan curvature derived from merged hgt Meters 32-bit real 0 NaN N/A N/A
PROFILE (PROFC)¹ Profile curvature derived from merged hgt Meters 32-bit real 0 NaN N/A N/A
SWBD Updated SRTM water body data (i.e., water mask) Class 8-bit unsigned integer N/A N/A 0 land, 255 water N/A

¹Units for PLAN and PROFILE layers are inverse meters.

About the image

NASADEM Slope and Curvature data over the Grand Canyon, 2000.

View full-size image


User Guide
Shuttle Radar Topography Mission (JPL) Webpage

Using the Data

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