LP DAAC GDEM Distribution Milestone / Re-distribution Update

October 06, 2009
By: LP DAAC

The Land Processes (LP) Distributed Active Archive Center (DAAC) distributed over 1 million ASTER Global Digital Elevation Model (GDEM) scenes since release on June 29th, 2009. Please visit the ASTER GDEM one-pager for additional information.

The LP DAAC has created an FAQ clarifying the ASTER GDEM re-distribution policy, which is as follows:

No charge data access is subject to the following redistribution and citation policies. To order ASTER GDEM, users must agree to redistribute data products only to individuals within their organizations or projects of intended use, or in response to disasters in support of the GEO Disaster Theme. Additionally, when presenting or publishing ASTER GDEM data, users agree to include a citation stating that "ASTER GDEM is a product of METI and NASA."

"Because there are known inaccuracies and artifacts in the data set, please use the product with awareness of its limitations. The data are provided "as is" and neither NASA nor METI/ERSDAC will be responsible for any damages resulting from use of the data."

ASTER GDEM Redistribution

Why are there restrictions on the redistribution of the ASTER GDEM?

The ASTER GDEM is a joint contribution by NASA and the Ministry of Economy, Trade and Industry of Japan (METI) to the Global Earth Observation System of Systems (GEOSS). As such, both METI and NASA desire to understand the uses of the ASTER GDEM, expressed as one the GEOSS applications themes: disasters, health, energy, climate, water, weather, ecosystems, agriculture or biodiversity. This requires both the registration of users, and restrictions on redistribution, to capture the intended use in terms of the GEOSS themes. These few restrictions on the ASTER GDEM commenced with the public distribution of tiles on June 29, 2009 and will continue through the life of the mission. Public access to the ASTER GDEM requires registration and acknowledgement of these restrictions at both the US and Japan server locations. All registration is kept confidential and is used solely for distribution metrics and possible notification of updates to the ASTER GDEM.

What restrictions apply to the redistribution of data?

The general principle is one of reversibility: If someone can recover the original x-y-z values from the new product, then that new product can NOT be re-distributed. This can also be defined as lossless recovery.

What are some examples of derived products that can NOT be re-distributed?

Transforming the data from GeoTIFF format to ESRI format

Mosaicking or subsetting the data at the native (1 arc-second) or better resolution to serve up areas different than the original 1x1 degree tiles

Changing the units from meters to feet
What are some examples of derived products that are re-distributable?

Re-projection that involved re-sampling, including nearest neighbor in cases where the reprojection involves more than a simple translation of an integer number of GDEM pixels.

Creating a slope map

3-D perspective visualizations
Can “flyover” movies created using ASTER GDEM data be re-distributed?

Flyover movies may be re-distributed if the final product is produced in a format that will not allow the recovery of the original data (e.g., avi, Quicktime, wmv).

Can images created for publication or Web 2.0 applications (e.g., Wikipedia) using ASTER GDEM data be re-distributed?

Images that are created using GDEM data may be re-distributed through publications or social media applications. Papers citing such articles may be re-distributed as well.

Please contact LP DAAC User Services, if additional information is required or for any further inquiries.

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