pytroll
Relicense to Apache Version 2
Overview
The maintainers of this project and some leading members of the Pytroll organization would like to re-license the pycoast Python package. We would like to first ask for opinions and permission from existing contributors of the project before making this change official. The software source code would change from a GPL Version 3.0 or Later license to an Apache Version 2 license. A simple non-exhaustive summary of these licenses and their differences can be found at the following URLs along with the full text of the license:
https://www.tldrlegal.com/license/gnu-general-public-license-v3-gpl-3
https://www.tldrlegal.com/license/apache-license-2-0-apache-2-0
Purpose
By moving away from the current GPLv3 license to a more permissive license we hope to encourage more collaboration. We also hope this opens the doors for more funding opportunities as some grants have explicitly not funded non-permissive/copyleft licenses like GPLv3.
This re-licensing does not change any understanding or assignment of copyright for this project. Copyright notices will remain with the collective "pycoast developers" identifier.
Why not license X?
The Apache Version 2 license was chosen because it is a permissive and open license like the MIT or BSDv3 licenses. It has the additional requirement that any modified files must "carry prominent notices" stating that changes were made to the original work. Lastly, Apache Version 2 is a very popular license even if other licenses may provide similar permissions and restrictions.
What do we want from you (an existing contributor)?
Please comment on this GitHub issue or contact a project maintainer (see contributor list below) with your approval (ex. "I approve") or disapproval (ex. "I do not approve") or other feedback about this planned re-licensing. We can contact contributors by email if necessary or requested.
Contributor and Approval List
- [x] @djhoese (maintainer)
- [x] @mraspaud (maintainer)
- [x] @pnuu (maintainer)
- [x] @adybbroe
- [x] @avalentino
- [x] @lobsiger
- [x] @loreclem
- [x] @mitkin
- [x] @sebastic
- [x] @thorsteinssonh
Edit: GitHub's contributor API missed some people
- [x] @storpipfugl
- [x] @howff
- [x] @talonglong
- [x] @yufeizhu600
- [ ] s.cerino
Hi all, Martin pointed me to this :) I certainly approve - and to make things easier in the future I feel that active pytroll-org developers best suited to make decisions about any code or contributions I made, license or otherwise. No need to consider my approval for anything in the future :) - Also the IMO bosses were extremely happy that I got to take part in this wonderful software development and I learned so much from working with you during my time at the IMO.
My contribution is trivial and therefor likely not copyrightable, but I consent to relicensing none the less.
@storpipfugl @howff @talonglong @yufeizhu600 GitHub's API didn't list you all. What are your thoughts on this?
I am interested to know the reasons
- "we hope to encourage more collaboration" - who at the moment is refusing to collaborate, based on the license?
- "some grants have explicitly not funded non-permissive/copyleft licenses" - which grants?
Redistribution Conditions GPLv3 Must include source code, modifications under GPLv3 Apachev2 Must include license, no obligation to open source
Compatibility with Proprietary Software GPLv3 Requires derivative works to be open Apachev2 Permits proprietary use and integration
Based on the above I can only assume that it's grants from commercial companies, that want to pay for open source development, but then take the resulting code private into their own proprietary products.
(I'm not refusing, by the way, just interested)
No problem @howff. So I'll admit when I wrote the original template for this issue (which I'm using in other pytroll relicensing issues too) the "some grants" sentence was based on memory. When I went and tried to find the exact language from the call for proposals that I had in mind, it looks like GPL is accepted. That said, since we've started this venture, we've gotten multiple people that have brought up GPL being an issue. For example, some US organizations that talked to me this week about potential funding said that LGPL in pyresample is fine, but GPL in Satpy and other libraries scared their lawyers. Additionally, @mraspaud has mentioned to me that multiple people at the EUMETSAT conference this week have expressed their approval or enthusiasm for the license change(s).
As for the license conditions and compatibility, GPLv3 not only requires it to be open but for it to be GPLv3 specifically (or GPLv3 compatible) which most other open source licenses are not. Additionally, GPLv3 was initially used to "force" modifications to make their way back to the project or at least be publicly available. Apachev2 also says that people have to be explicit about what was modified from the original so it seemed like a nice middle ground between GPLv3 and MIT.
The ability to work with commercial entities would also be nice.
Let me know if you have any other questions or suggestions.
I approve
Am Di., 23. Sept. 2025 um 15:17 Uhr schrieb storpipfugl < @.***>:
storpipfugl left a comment (pytroll/pycoast#146) https://github.com/pytroll/pycoast/issues/146#issuecomment-3323983553
Approved
— Reply to this email directly, view it on GitHub https://github.com/pytroll/pycoast/issues/146#issuecomment-3323983553, or unsubscribe https://github.com/notifications/unsubscribe-auth/AYJJ2UZI2K4O5S3TU6YYLLT3UFCADAVCNFSM6AAAAACGU3MKJOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTGMRTHE4DGNJVGM . You are receiving this because you were mentioned.Message ID: @.***>
