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The goal of CIG is to develop software in support of Earth science research and education. Since a major aim is for the widest availability and impact of all CIG developments and software, all software CIG develops will be open source.

In order to uphold these principles, CIG adopts this Policy with the following aspects:

  1. CIG will maintain a software repository on the World Wide Web at in which software can be checked out without restrictions as software is developed. In order to ensure the quality of CIG software, the privilege to check software back into the repository by members of the CIG community will be made on a case-by-case basis.
  2. Some software will be solely developed by the CIG staff. In such cases, the copyright will be retained by the Regents of the University of California and distributed under the Free Software Foundation’s GNU General Public License (GNU GPL), unless otherwise stated.
  3. Some software will be written in collaboration between CIG staff and other organization(s) or individual(s). In each case, but before the collaboration is initiated, CIG must enter into an agreement that clearly specifies who the copyright holder(s) will be and the terms of the software release. When possible, copyright shall belong to all contributing parties, and the software released under the GNU GPL.
  4. Some software will be preexisting and not necessarily free from existing third-party copyrights and licenses. In the event that CIG wishes to use or to modify, improve, and/or distribute such software, CIG will, with its collaborators, determine who the copyright holders are and enter into an agreement to have the resulting software released under an open source license, preferably the GNU GPL. In exceptional cases, CIG will consider a different license as long as it is free for non-commercial use but otherwise satisfies the principles of open source software.
  5. In order to maximize the benefit to the Community, the details of this policy may change from time to time, but such changes will always be subject to Member input and discussion and then final approval by the CIG Executive Committee.

As adopted by the CIG Executive Committee on October 17, 2005

GNU General Public License

All CIG hosted software is released through an open source software license.  CIG will consider open source licenses that are free for non-commercial use but prefers the GNU General Public License. For more information on open source licensing see the Open Source Inititative.

The GNU GPL has two versions that are actively used in many open source communities:

  • GNU GPLv2 (June 1991)
  • GNU GPLv3 (June 2007)

GPLv3 addresses issues that were not sufficiently covered in GPLv2 including license compatability and digital rights management; contains an explicit patent;and states that there is no requirement to disclose source code in an ASP use.  Most software in the CIG repository is released under GPLv2.  Please consult each software page for specific licensing information. Note that version 1.0 is not recommended for use. 

For more information see OSI GNU GPL and

Information on implementation can be found here.

Other Licenses

CIG codes also use the following licenses:

Other Resources

Introduction to Software Licensing  (2018-12-05) [IDEAS Productivity]
Presenter: David E. Bernholdt, ORNL
Archives: Slides (PDF @ FigShare) | Video (YouTube) | Q&A (PDF)