ASTER Global Digital Elevation Map

Geschrieben von am .

Das Höhenmodell ASTER GDEM ist aus Stereobildern berechnet, die vom Messinstrument ASTER (offizielle Seite der NASA) des Erdbeobachtungssatelliten Terra aufgenommen worden.

Die Daten sind für nichtkommerzielle Nutzung kostenlos verfügbar.

Qualität:

Jonathan de Ferranti hat auf viewfinderpanoramas.org die ASTER-GDEM-Daten ausführlich besprochen.

Download:

Die Seite earthexplorer.usgs.gov stellt (u.a.) auch die ASTER-GDEM-Daten bereit. Bis zur Voransicht kommt man anonym, für den Download ist eine Registrierung erforderlich.

Das GeoTIFF enthält 3601×3601 Werte für in meinem Beispiel die Breiten +51°00'00" bis +50°00'00" mit einer Schrittweite von 1" und die Längen +7°00'00" bis +8°00'00" mit einer Schrittweite von 1".

Eine Bogensekunde (1') ist in Nord-Süd-Richtung etwa 30m (Erdumfang 40.000km ÷ 360° ÷ 60' ÷ 60").
In West-Ost-Richtung nimmt der Wert mit dem Cosinus der Breite zu den Polen hin ab; innerhalb Deutschlands reicht der Cosinus von 0.7 bis 0.6, 1' entspricht also etwa 20m.

Man kann bestimmte Download-Seiten auch direkt aufrufen:
http://earthexplorer.usgs.gov/metadata/4220/ASTGDEMV2_0N50E007/

Lizenz:

Die Nutzungsbedingungen zu den ASTER-Daten muss man sich zusammensuchen:

Projekt-Seite: asterweb.jpl.nasa.gov

Die Unterseite Get ASTER Data der offiziellen Webseite enthält einen Link zum Earth Explorer mit diesem Hinweis:

Free ASTER data for all users: ASTER L1B data over the U.S. and territories, the ASTER GDEM, and NAALSED products.

Free klingt vielversprechend … steht aber nur™ für free of charge.

Download-Seite: earthexplorer.usgs.gov

Wählen wir im Earth-Explorer unter Data Sets im Bereich Digital Elevation den Punkt ASTER GLOBAL DEM aus, bekommen wir einen Teil der Bedingungen (are not limited to) zu sehen:

Data Set Message

EarthExplorer Aster Global DEM

You have selected a dataset that has data restrictions. These data are subject to terms and conditions as specified by the data provider. Restrictions include but are not limited to:

  1. ASTER Global DEM (GDEM) data are subject to redistribution and citation policies. Before ordering ASTER GDEM data, 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.
  2. When presenting or publishing ASTER GDEM data, users are required to include a citation stating, "ASTER GDEM is a product of METI and NASA."
  3. 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.

The USGS will not be held responsible or liable for misuse or misrepresentation by the end users and is not required to enforce these provisions beyond communicating them to the user. It is the responsibility of the user to adhere to these terms and conditions.

If you agree to these terms, click OK to proceed.

Arbeiten wir uns bis zum Download vor (Registrierung erforderlich), bekommen wir den nächsten Lizenz-Happen: 

Land Processes Distributed Active Archive Center
(LP DAAC)

ASTER Global DEM (GDEM) data are subject to redistribution and citation
policies. Before ordering ASTER GDEM data, 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.

When presenting or publishing ASTER GDEM data, users are required to include a
citation stating, "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.

Users will not use the GDEM data for purposes of monetary reward by means of the
sale, resale, loan transfer, hire or other form of commercial exploitation;

Users accessing the data may generate derived products and re-distribute such
derived products only if someone cannot recover the original x-y-z values from
the new product;

It is the responsibility of the user to adhere to these terms and conditions.

Archiv-Seite: lpdaac.usgs.gov

Am Ende der Seite Get ASTER Data findet sich der Hinweis:

For additional information on ASTER data access, distribution, and citation policies, please visit the LP DAAC ASTER Policies page.

Der Link ist tot; die Fehlerseite aber schlägt ASTER Policies vor, und da finden wir die ASTER Data Redistribution Policies:

ASTER Global DEM (GDEM) data are subject to redistribution and citation policies. Before ordering ASTER GDEM data, 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. When presenting or publishing ASTER GDEM data, users are required to include a citation stating, "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.

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?

  1. Transforming the data from GeoTIFF format to ESRI format
  2. 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
  3. Changing the units from meters to feet

What are some examples of derived products that are re-distributable?

  1. Reprojection 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
  2. Creating a slope map
  3. 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.

Die Frage was darf ich weitergeben, wird beantwortet: Schummerungen und Höhenlinien sind erlaubt. Zur kommerziellen Nutzung steht hier nichts.☹