License

[zxdawn]

@TAdeJong I see Satpy will switch to Apache Version 2. Should we also use that?

pytroll/satpy#3259

[TAdeJong]

I would indeed prefer to use Apache or a similar license. However, I am getting out of my depth fast. Related is #138: We incorporate (adapted?) code from ddeq, which is licensed under GNU LESSER GENERAL PUBLIC LICENSE 2.1. I think this might mean we have to stick to a GPL license. We can cross-check with the SRON data stewards, who should have more expertise here.

[zxdawn]

I would say our code doesn't depend heavily on ddeq? Maybe we can use Apache ....

[zxdawn]

See this comment below:

The Apache license is GPL compatible, but more permissive, and gives the opportunity to add a NOTICE file which you can use to mention citation information.

[zxdawn]

I checked the email with Jelle long time ago (attached below). You're right, we need to stick to GPL because of ddeq ....

---

Choosing a license depends on a couple of things. Do you know whether the external libraries or modules that you use have a license? If the software that you depend on is licensed under GPL, then your code should in principle be released under a GPL compatible license as well. Because of these ‘viral’ properties of GPL, it is not recommended to choose this for your software if you have a choice, because it forces certain limitations on what people can do with your software.

ASTRON figured out a license policy for their software that can be an inspiration for us. This is what they provide:
https://doi.org/10.5281/zenodo.3479828. NWO just promotes the use of permissive open source licenses and does not recommend any licenses in particular.

The ASTRON advice is to choose the Apache 2.0 license, unless there are reasons to choose a GPL license (for example if your code depends heavily on other GPL code). The Apache license is GPL compatible, but more permissive, and gives the opportunity to add a NOTICE file which you can use to mention citation information.

If you want more information about all the licenses, you can check https://choosealicense.com/ or we can also chat in person if you like. Licenses are a bit of a complicated topic if you dive deeper into it.