After February 16, 2023, the long name GNSS products archived at the CDDIS will follow the Guidelines for Long Product Filenames in the IGS version 2.0. These guidelines are available at https://files.igs.org/pub/resource/guidelines/Guidelines_For_Long_Product_Filenames_in_the_IGS_v2.0.pdf. For more information, please see IGSMail message 8309 sent February 3, 2023. https://lists.igs.org/pipermail/igsmail/2023/008305.html.

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CDDIS Archive Access

The Crustal Dynamics Data Information System (CDDIS) supports data archiving and distribution activities for a global user community. Since its inception, users have relied on anonymous ftp for accessing and downloading files from the system. Although this protocol allows users to easily automate file downloads, many organizations, data systems, and users have already migrated from ftp or are actively pursuing a move away from the protocol due to problems from a system and security standpoint. U.S. Government agencies have become increasingly concerned about this legacy protocol and ensuring data integrity for the user community and have disallowed the use of the ftp protocol. The CDDIS, located at NASA GSFC, has therefore addressed these concerns and provided alternative methods for access to its archive for continued easy and automated download of its contents.

Therefore, the CDDIS discontinued anonymous ftp access to its archive in October 2020. Users must now utilize more secure access protocols such as https or ftp-ssl.

In order to access the CDDIS archive, users will need to use a client that supports Transport Security Layer (TLS). When using the https protocol (for example, cURL, Wget, or Python commands/scripts) users will need to have an Earthdata Login account. In addition, when utilizing the cURL and Wget, users will need to create a .netrc file; instructions for creating this file are available.

Examples of accessing the archive via TLS using various methods can be found below. Click on the name of a method to view the instructions; click on a link within a method to see expected results of that command. In the examples, <email address> means type in your actual email address without the < and > symbols.

Click on an example in the table below; the example details will appear below the table.

Client HTTPS Access ftp-ssl Access
https://cddis.nasa.gov/archive/ ftp://gdc.cddis.eosdis.nasa.gov/
cURL
Wget
(version ≥ 1.18)
lftp
Python 3
Java