ASTER and ETM+ data update (long)
Rick Wessels
rwessels at usgs.gov
Wed Mar 12 11:56:37 MST 2003
Hi,
It has been a good year for ASTER acquisiton as much data is currenly
available for most regional centers. In addition to some ASTER
acquisition stats, I want to update you on several important issues
related to finding and ordering available ASTER and Landsat 7 data.
(Sorry for the long note, but there is a lot to say : )
1. ASTER acquisition and processing stats
2. Signing up for free ASTER data as a NASA collaborator
3. Tools for finding ASTER data
4. Landsat 7 data available for ftp download
1. ASTER acquisition and processing stats
Our local ASTER database shows the total number of all ASTER scenes
globally with unique date/times at EDG are: 460,000 L1A and 95,000 L1B
(+ 2818 special GLIMS L1B from EDC)
Of the total L1A,
53,500 any season or quality intersect our GLIMS STARs
33,782 of these are daytime scenes with a NOR or LOW gain setting ( no
cloud assessment)
18,661 of the above are listed with <= 30% scene cloud cover
1362 of 1632 GLIMS STARs (83%) intersect at least one of the 18,661 L1A
scenes
Of the total L1B (totals include the 2818 EDC processed L1B scenes not
available in the EDG. These will eventually be available at on an EDC
ftp site),
11,440 any season or quality intersect our GLIMS STARs
7,960 of these are daytime scenes with a NOR or LOW gain setting ( no
cloud assessment)
7,705 of the above are listed with <= 30% scene cloud cover
1323 of 1632 GLIMS STARs (81%) intersect at least one of the 7355 L1B
scenes.
The majority of the non-acquired STARs are Antarctic wide-pointing,
Central Asia, Russia, Southern South America, and South Alaska/W. BC.
The most troubling issue is that many the 15,000+ scenes that are listed
with a scenecc > 30% are likely cloud-free. Conversely, roughly 25% of
the listed low-cloud scenes are actually cloudy. Manual assessment is
currently the only way to know for sure. As the above numbers suggest,
there may be another 6000 to 8000 L1A scenes that may be good enough to
be processed to L1B, but currently are not. Most of these lie in the
Arctic and Antarctica. As I understand it, EDC plans to process much of
the older L1A global archive to L1B over the coming year, so many of the
useful L1A scenes will eventually become L1B.
2. Signing up for free ASTER data as a NASA collaborator
After several months of waiting and testing, we have come to the
conclusion that NASA will grant free ASTER data to our GLIMS colleagues
for our glacier mapping efforts. According to NASA: "
* ASTER data will be provided at no cost to current NASA-funded
researchers and affiliated users. Investigators who receive funds
directly from NASA through a Grant, Contract, or Cooperative
Agreement will be eligible to receive the data without charge.
Affiliated users including researchers who receive NASA research
funds through a third party, researchers from interagency and
international partners affiliated with NASA through joint
projects, and education users (including NASA-sponsored and
non-NASA-sponsored) should submit a request to be granted access
to data without distribution charge to oescomm at mail.hq.nasa.gov
<mailto:oescomm at mail.hq.nasa.gov> using the form at
http://edcdaac.usgs.gov/aster/application.html
<http://edcdaac.usgs.gov/aster/application.html>."
When you submit an application include the items:
Project PI: Jeff Kargel (replacing PI- Hugh Keiffer)
Project Title: Global Land Ice Measurement from Space (GLIMS)
NASA program affiliation: NASA ESE Pathfinder
Research description:
"The project GLIMS (Global Land Ice Measurements from Space) is one of
the ASTER Science projects. GLIMS aims at - for the first time -
inventorying and monitoring the world's glaciers from space. GLIMS is
based on data from ETM+ and ASTER. The current GLIMS-PI is Jeff Kargel,
USGS Flagstaff AZ, Hugh Kieffer, also of the USGS Flagstaff, cofounded
GLIMS as an U.S. ASTER Science team member.
Cf. www.glims.org, jkargel at usgs.gov
The present applicant is part of GLIMS in the following ways:
(1) ##YOUR NAME## is the (##RC chief, Steward, RC assistant, etc##) for
GLIMS, and in this function
responsible for mapping ##YOUR RC's## glaciers from space.
(2) any research or contribution details that you may want to add.
The above activities rely on free access to a significant number of
ASTER scenes. Continued free access to ASTER data for the applicant
would, therefore, substantially support the above activities, and also
lead to further promotion of ASTER and GLIMS."
NOTE: Some of our testers received an email response within two days
and others never received a response, but found that free access was
indeed granted. When you place an order for ASTER data as a NASA user,
you must always use the email address that you submitted with your
application. After the order is submitted, you will get two immediate
email responses: one shows your total cost as 'number of scenes times
$55 per scene', the other says that NASA will pay for it and your total
cost is $0.00. If you do not receive a "NO COST" email with your order,
you should contact EDC.
3. Tools for finding ASTER data:
There are several tools available for finding ASTER scenes over your
areas of interest.
a. ASTER browse viewer: http://edcdaac.usgs.gov/aster/glovis.html
New java based viewer that shows many ASTER VNIR decorrelation
browse images in one map view. These L2 browse images are a bit larger
than the standard L1 browses. The main limitation is that <10,000 of
the nearly 500,000 ASTER scenes acquired are currently available via
this interface. EDC and Japan are currently working to create larger
browse images for all products. Stay tuned ...
b. EOS Data Gateway: http://edcimswww.cr.usgs.gov/pub/imswelcome/
The standard place for finding and ordering ASTER data. A bit
slow, but it works...
c. GLIMS interactive scene finder: http://www.glims.org/astermap.html
Shows scene footprints of all ASTER scenes over glaciers. Can
do simple queries to generate GranuleID lists that may be ordered using
option "b" above.
d. The shapefiles displayed in c. above are often available on our
anonymous ftp site at:
ftp://ftpflag.wr.usgs.gov/pub/outgoing/rwessels/ASTERDB if you want to
create more sophisticated searches using your local GIS tools.
4. Landsat 7 data available for ftp download
A reminder that we have over 150 Landsat 7 ETM+ scenes now available
online. John Dwyer and others at the EROS Data Center (EDC) have
constructed an anonymous ftp site with Landsat data sorted into
directories for each regional center. The FTP data directories contain
ETM+ data and browse images. The general structure is an over-arching
GLIMS directory, under which exists a subdirectory for each RC. Under
the RC subdirectories are an ASTER and a Landsat7 subdirectory. We're
populating the Landsat7 subdirectory with each band as a separate file
that has been Gzip-compressed. There is a Readme file, and a browse
image, for each scene. Most of the scenes are in Geotiff format (except
for some of Alaska, W. Canada, and lower US).
To access the data:
1. ftp edcsgs16.cr.usgs.gov (or
ftp://edcsgs16.cr.usgs.gov/orders/glims using internet explorer)
2. User=anonymous, Password=Your_email_address
3. cd /orders/glims
4. ls (to list the Regional Center subdirectories)
5. cd RC__ (to the RC of interest)
6. cd Landsat7
7. binary (set to binary for transfer)
If you have any other ETM+ data that you would be willing to share,
please let me know. We may be able to buy a few more scenes this year,
so please inform us if you have identified any new or critical scenes.
As always, if you have any questions, we will do our best to get back to
you with a useful answer.
Warm Regards,
Rick Wessels
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Rick Wessels, Ph.D. rwessels at usgs.gov
Arizona State University / U.S. Geological Survey
2255 N. Gemini Drive Phone(928)-556-7022
Flagstaff, AZ 86001 FAX -7014
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