ASTER Global Digital Elevation Model (GDEM)
About ASTER GDEM
ASTER GDEM is an easy-to-use, highly accurate DEM covering all the land on earth, and available to all users regardless of size or location of their target areas.
Anyone can easily use the ASTER GDEM to display a bird’s-eye-view map or run a flight simulation, and this should realize visually sophisticated maps. By utilizing the ASTER GDEM as a platform, institutions specialized in disaster monitoring, hydrology, energy, environmental monitoring etc. can perform more advanced analysis.
The ASTER Global Digital Elevation Model (ASTER GDEM) is a joint product developed and made available to the public by the Ministry of Economy, Trade, and Industry (METI) of Japan and the United States National Aeronautics and Space Administration (NASA). It is generated from data collected from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), a spaceborne earth observing optical instrument.
The first version of the ASTER GDEM, released in June 2009, was generated using stereo-pair images collected by the ASTER instrument onboard Terra. ASTER GDEM coverage spans from 83 degrees north latitude to 83 degrees south, encompassing 99 percent of Earth’s landmass.
The improved GDEM V2 (released October 17, 2011) adds 260,000 additional stereo-pairs, improving coverage and reducing the occurrence of artifacts. The refined production algorithm provides improved spatial resolution, increased horizontal and vertical accuracy, and superior water body coverage and detection. The ASTER GDEM V2 maintains the GeoTIFF format and the same gridding and tile structure as V1, with 30-meter postings and 1 x 1 degree tiles.
Version 2 shows significant improvements over the previous release. However, users are advised that the data contains anomalies and artifacts that will impede effectiveness for use in certain applications. The data are provided “as is,” and neither NASA nor METI/Japan Space Systems (J-spacesystems) will be responsible for any damages resulting from use of the data.
Comparison with other DEMs
10 m mesh digital elevation data
|ASTER||Space shuttle radar||From organizations around the world that have DEM data||1:25,000 topographic map|
Generation and distribution
|2009 ~||2003 ~||1996 ~||2008~|
Data acquisition period
|2000 ~ ongoing||11 days (in 2000)|
DEM accuracy (stdev.)
|83 degrees north ~ 83 degrees south||60 degrees north ~ 56 degrees south||Global||Japan only|
Area of missing data
|Areas with no ASTER data due to constant cloud cover (supplied by other DEM)||Topographically steep area (due to radar characteristics)||None||None|
Areas of DEM application
1. Stereoscopic visualization of satellite and other two-dimensional images
2. Automated calculation of slope direction and angle, catchment area, faults, etc.
As a contribution from METI and NASA to the Global Earth Observation System of Systems (GEOSS), ASTER GDEM V2 data are available free of charge to users worldwide from the Land Processes Distributed Active Archive Center (LP DAAC), NASA Reverb and J-spacesystems.
Step-by-Step ASTER GDEM Download
Below I will explain to you as simple as I can How to download ASTER GDEM for an area of interest using J-spacesystems’ website.
Visit J-spacesystems website
Exact URL: http://gdem.ersdac.jspacesystems.or.jp/
Click “Login” at the left sidebar if you already have an account or click “Register & Modification”
At the next screen the system ask you to confirm user information. If it’s correct click “Register”, otherwise click “Back” and correct any errors.
If anything is ok, your next screen is the homepage of J-spacesystems but there is one difference now, you can see your username up in the right of the frontpage. This means you are already logged into the system so you don’t have to “Login” again.
Click “Search” from the sidebar in the left.
You have four methods to select your area of interest:
- Select tiles directly
- Select tiles by polygon (You have to draw a polygon)
- Select tiles by shapefile (You have to upload the shapefile)
- Select tiles by coordinate (You must enter coordinates)
Let’s see how to select tiles directly.
1. Click Select tiles directly.
2. Use zoom bar to zoom in at your area of interest.
3. Click “Grid” to view the grid on the map.
4. Click “Start” button and then click as many tiles as you need to cover your area of interest on the map…
5. When you are ready click “Next”…
At the next screen you can see all the selected tiles as zip files ready to be downloaded. You can also unselect some of them if you don’t really need them. If everything is ok click “Next”
Before downloadng ASTER GDEM tiles, firstly choose a category from the pulldown menu below. Then, you are required to agree to the “ASTER GDEM Policy”.
At the final step (screen) you can see again all the selected tiles as zip files and a download button at the right. Click them to download the zipped raster files.
Source: J-spacesystems & NASA