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- #DIGITAL TERRAIN MODEL DOWNLOAD MANUAL#
- #DIGITAL TERRAIN MODEL DOWNLOAD ARCHIVE#
- #DIGITAL TERRAIN MODEL DOWNLOAD SOFTWARE#
As an on-demand product, the ASTER DEM is available to users via FTP-Pull only. ASTER DEMs are available from the LP DAAC through the EOS Data Gateway (EDG) as an on-demand product only.ĭistribution Media. ASTER DEMs are available from the LP DAAC in GeoTif format only. ASTER DEMs produced by the LP DAAC are referenced to the Earth's geoid using the EGM96 geopotential model. The ASTER DEM available from the LP DAAC is strictly an on-demand product.
#DIGITAL TERRAIN MODEL DOWNLOAD ARCHIVE#
The previously existing ASTER DEM archive is no longer available. For best results and to the extent possible, users are reminded to select high-quality, cloud-free Level-1A data as input for generating DEMs they order.ĪSTER DEM Archive Eliminated. Cloudy areas typically appear as bright regions, rather than as manually edited dark areas. Any failed areas, while infrequent, remain as they occur. Larger water bodies are detected and typically have a single value, but they no longer are manually edited.
#DIGITAL TERRAIN MODEL DOWNLOAD MANUAL#
Compared to ASTER DEMs previously available from the LP DAAC, users likely will note some differences in ASTER DEMs produced by the new system, because DEMs now are produced automatically, with no manual editing. Users likely will find that the DEMs produced by the new DAAC system have accuracies approaching those specified in the ATBD for absolute DEMs. Demand for the previously available ASTER absolute DEM was very low, and product accuracies frequently were diminished by poor quality user-supplied GCPs. LP DAAC no longer produces an ASTER absolute DEM (i.e., those produced with user-supplied GCPs). In addition to higher production throughput and improved accuracy of the relative DEM, users need to be aware of other important characteristics of ASTER DEM generation at the LP DAAC: Important Characteristics of the LP DAAC ASTER DEM Product Validation testing has shown that DEMs produced by the new system frequently are more accurate than 25 meters RMSExyz. The accuracy of the new DEMs meets or exceeds accuracy specifications set for the ASTER relative DEMs by the applicable Algorithm Theoretical Basis Document (ATBD).
#DIGITAL TERRAIN MODEL DOWNLOAD SOFTWARE#
The new software implemented and released on has the capability to produce 50 or more ASTER relative DEMs per day in batch mode operation. That decision followed an extensive assessment of the accuracy of ASTER relative DEMs produced by a variety of ASTER DEM generation software, and was made in response to a desire by NASA management to increase the rate of ASTER DEM production at the LP DAAC. In late 2005, the decision was made to change the ASTER DEM production software at the LP DAAC. In addition, the LP DAAC became aware of an apparent degradation in the accuracy of its ASTER relative DEM over time.ĭecision to Change the ASTER DEM Production Software The ASTER relative DEM turned out to be one of the most popular ASTER data products among users, and the backlog of orders for that product grew very large. The ASTER DEMs were the only higher-level products that were archived and available for ordering by all users. Unlike other ASTER standard data product generation systems, the DEM generation system was designed to produce only one or two DEMs per day. Two versions of the product were available: a relative DEM, production of which required no ground control points (GCPs), and an absolute DEM, which required user-supplied GCPs. Since April 2001, the LP DAAC has offered a digital elevation model (DEM) produced from ASTER Level-1A data as a standard data product. From LP DAAC: Change in the ASTER DEM Production Software at the LP DAAC