AST14DEM v003

ASTER Digital Elevation Model


PI: U.S./Japan ASTER Science Team

Description

The ASTER Digital Elevation Model (AST14DEM) product is generated using bands 3N (nadir-viewing) and 3B (backward-viewing) of an ASTER Level 1A image acquired by the Visible and Near Infrared (VNIR) sensor. The VNIR subsystem includes two independent telescope assemblies that facilitate the generation of stereoscopic data. The band 3 stereo pair is acquired in the spectral range of 0.78 and 0.86 microns with a base-to-height ratio of 0.6 and an intersection angle of 27.7 degrees. There is a time lag of approximately one minute between the acquisition of the nadir and backward images.For a better understanding, refer to this diagram depicting the along-track imaging geometry of the ASTER VNIR nadir and backward-viewing sensors.

The accuracy of the new LP DAAC produced DEMs will meet or exceed accuracy specifications set for the ASTER relative DEMs by the Algorithm Theoretical Basis Document (ATBD). Users likely will find that the DEMs produced by the new LP DAAC system have accuracies approaching those specified in the ATBD for absolute DEMs. Validation testing has shown that DEMs produced by the new system frequently are more accurate than 25 meters root mean square error (RMSE) in xyz dimensions.

Characteristics

Improvements/Changes from Previous Versions

Starting in early summer of 2006, LP DAAC has implemented new production software for efficiently creating quality DEMs. Based on an automated stereo-correlation method, the new software generates a relative DEM without any ground control points (GCPs). It utilizes the ephemeris and attitude data derived from both the ASTER instrument and the Terra spacecraft platform. The new ASTER DEM is a single band product with 30 meter horizontal postings that is geodetically referenced to the UTM coordinate system and to the Earth's geoid using the EGM96 geopotential model. Compared to ASTER DEMs previously available from the LP DAAC, users likely will note some differences in ASTER DEMs produced by the new system. These differences are due to the DEMs no being produced automatically with no manual editing. Larger water bodies are detected and typically have a single value, but they no longer are manually edited. Any failed areas, while infrequent, remain as they occur. Cloudy areas typically appear as bright regions, rather than as manually edited dark areas.

Collection and Granule

Collection

Characteristic Description
CollectionTerra ASTER
DOI10.5067/ASTER/AST14DEM.003
File Size~12 MB
Temporal ResolutionOther
Temporal Extent2000-03-06 to Present
Spatial ExtentGlobal
Coordinate SystemUniversal Transverse Mercator (UTM)
DatumWorld Geodetic System (WGS84)
File FormatGeoTIFF
Geographic Dimensions~60 km x 60 km

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers1
Columns/RowsVaries by scene
Pixel Size30 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor Additional Offset
Band 1 Digital Elevation Model Meters 16-bit signed integer N/A N/A -32768 to 32768 N/A N/A

Documentation

Using the Data

E-Learning

View from NASA Terra's Zoom Lens: All About the ASTER Sensor

Data In Action

Highlights from the NASA DEVELOP National Program Summer 2017 Term

Highlights from the Literature: October to December 2016

Tools

Citation

DOI: 10.5067/ASTER/AST14DEM.003

About the Image