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Use ASTER GDEM distribution site
- This page explains the use of ASTER GDEM site and features of ASTER GDEM.
For features of ASTER GDEM, go to the following page.
ASTER Global Digital Elevation Model(GDEM) Features
- The use of ASTER GDEM distribution site
ASTER GDEM distribution site is easy to use for all users.
1.Data search
When clicking [Search] menu, map screen appears.
You can select tiles with one of following 4 search methods; [Select tiles directly], [Select tiles by polygon], [Select tiles by shape file] and [Select tiles by coordinates]. For map manipulation, click [Map Manipulation] button in Search page.
After selecting tiles, Login page or Agreement page appear. If you click [Agree] button, Download page appears, and you can download tiles.
2.User registration
To download ASTER GDEM, you need to register.
For user registration, you need to enter your individual information such as name, organization name, as well as your username and password.
3.Login
To download ASTER GDEM, you need to register and login.
You can login with registered username and password.
- Restriction for site use
In this site, some restrictions are set to avoid downloading troubles caused by heavy access traffic.
1.Access restriction
Simultaneous download is not possible by using the same client IP address.
Note that the tool for batch download by multi-session is not usable for high speed download.
In addition, note that if multiple PCs try to download from the same gateway address, they are regarded as one PC.
2.Bandwidth control
Bandwidth control is also set for website access.
Bandwidth control is set in service unit so that download is possible when the server is busy.
- Download
1.Number of simultaneous access
Up to 16 users can simultaneously download ASTER GDEM both in real-time download and backlog download. If the access number exceeds 16, the 17th download does not start until there is another opening.
2.Limit number of data download
The maximum tile number for a single download is 100. If you select more than 100 tiles and try to download them, the first 100 tiles are immediately downloaded while the 101st or later tiles are recorded in backlog, and downloaded by ftp later. In backlog download, the maximum tile number for a single download is also 100. For example, 200 backlogged tiles are downloaded in twice. Also, after the first 100 tiles are downloaded, download of the remaining 100 tiles is re-placed at the end of the download waiting list.
3.Limitation of backlog download
You can confirm the rough schedule to download the first 100 backlogged tiles on “Backlog reference” page. However, please note that if your PC is not ready to download in your turn, the download is re-placed at the end of the waiting list. In addition, if another user is placed on the last line of the waiting list, your order may be brought forward. However, even in this case, if your PC is not ready to download in your turn, the download is re-placed at the end of the waiting list.
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