FTP Access to GLIMS Data

by John Dwyer, Land Processes Distributed Active Archive Center
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About the Data on the FTP Site

As part of the Global Land Ice Measurements from Space (GLIMS), we have established a suite of FTP directories containing the following data and information:

1. Winzip files (i.e. 0002to0040.zip) containing JPEG images of ASTER VNIR bands 3b, 2, and 1 as red, green, blue.
2. An Excel workbook (L1BfromL1A_GLIMS_list_mmddyr.xls) containing results from quality assessment of ASTER scenes.
3. README file (README.txt or README.pdf).
4. Regional Center subdirectories (RC1 through RC24, and UNKNOWN_Antarctica)

The GLIMS FTP directories are set-up with an over-arching GLIMS directory, under which exists a subdirectory for each RC. Under the RC subdirectories will be an ASTER, Landsat7 (ETM+), and/or and MRLC (Landsat 7 ETM+) subdirectory, depending on which data are available.

GLIMS
  RC__
    ASTER
    Landsat7
    MRLC

The reason for two different subdirectories for Landsat 7 ETM+ data is to distinguish between the two different product generation systems at EDC. Data under the Landsat7 subdirectory were ordered through the EOS Data Gateway and created on the Level-1 Product Generation system (LPGS). The file naming convention using a band 7 file as an example is:

Data under the MRLC subdirectory were ordered through Earth Explorer and created on the National Landsat Archive Production system (NLAPS). The file naming convention using a band 7 file as an example, is:

All ETM+ scenes are in the UTM projection, and each band is stored as a separate file that has been Gzip-compressed. ASTER data are provided in the HDF-EOS format.

Accessing the Data on the FTP Site

The data may be accessed as follows:

1. ftp edcsgs16.cr.usgs.gov
2. User=anonymous, Password=Your_email_address
3. cd /orders/glims (to retrieve ETM+ or ASTER data files)
   1. The spreadsheet is L1BfromL1A_GLIMS_list_date.xls
   2. The JPEG images are grouped in .zip files named according to their respective range of records (row numbers) in the Excel spreadsheet.
   3. AST_L1B_dbID - same as Data Granule ID in the EOS Data Gateway (EDG)
   4. FileName - name of the ASTER HDF-EOS file that is online under /orders/glims/RC/ASTER
   5. RegionNumber - indexed to the Regional Center number on the Map of GLIMS Regions (can also be accessed through the GLIMS Glacier Database)
   6. AcquisitionDate - self-explanatory
   7. AcquisitionTime - self-explanatory
   8. Center Lat (degrees) - self-explanatory
   9. Center Long (degrees) - self-explanatory
   10. Cloud Cover(%) - visual assessment performed by EDC
   11. Comments - general observations on scene/data quality
4. 'ls' to list the Regional Center subdirectories from which to retrieve ETM+ or ASTER data)
5. Select the desired RC and data subdirectories from which to download
   1. Regional Center subdirectory naming convention is RCnn (Region Number), or scenes that were not easily tied to a RC (i.e. Unknown_Antarctica).
6. 'cd' RC__ (to the RC of interest)
7. 'cd' to ASTER, Landsat7, or MRLC
   1. Landsat7 (ETM+) The files are 1 band per scene, with the scene-id as the root of the filename, and these are Gzip compressed (*.tif.gz). There is also a Readme.GTF file for each scene.
   2. MRLC (Landsat 7 ETM+) The files are 1 band per scene, with the scene-id as the root of the filename, and these are Gzip compressed (*.gz). There is also a Readme.TXT file for each scene.
   3. ASTER For each ASTER scene, there is an .hdf and .met file, both of which are Gzip compressed (*.hdf.gz and *.hdf.met.gz)
8. 'binary' (set to binary for transfer)
9. 'get' or 'mget' desired file(s)

Please consult the GLIMS web site or the LP DAAC web site for further information.

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