There are several ways to access the CDDIS archive:
- via https at URL https://cddis.nasa.gov/archive/
- via ftp-ssl using the command line and gdc.cddis.eosdis.nasa.gov
How can I learn more about the formats used for CDDIS data sets?
All documents describing the formats of data available through the CDDIS can be found at URL https://cddis.gsfc.nasa.gov/archive/reports/formats.
What is the meaning of the .Z extension on filenames?
The .Z indicates the file was compressed using UNIX compression, e.g., the UNIX compress command. Users on UNIX systems can use the uncompress command to expand the file. Users on non-UNIX systems can consult the gzip web site. Note that ftps transfers of compressed files must be performed using binary mode.
Is the timestamp on archived files local or UTC?
The timestamp of all files in the archive refers to local time at the CDDIS (EST or EDT).
Where can I find the list of satellite identifiers for SP3 orbit files?
The list of satellite identifiers for SP3 orbit files is available at URL http://cddis.gsfc.nasa.gov/Techniques/sp3c_satlist.html.
What do all the acronyms mean?
The CDDIS acronym list is available at https://www.earthdata.nasa.gov/acronyms.
What is the index.html file found in the archive directories?
An index.html file is required in order for web browsers to be able to display the contents of a directory in a proper format. This file is used when accessing the CDDIS archive through https, not lftp. There is no harm in downloading this file; however, if you prefer to not retrieve the index.html file, you will need to modify your scripts to exclude any file named 'index.html' when downloading all files from a particular directory.
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