Clarify licenses

[dcanelhas]

Currently only some of the source files contain any sort of license information e.g. ndt_map.h has a copy of the BSD-3-clause license.

The ros wiki refers to BSD License for the perception stack and for individual packages but does not specify which one of the BSD Licenses is intended.

It would be helpful if the repository included a LICENSE file, indicating which parts of the sources are covered by what licenses.

[ksatyaki]

We have an open issue on the private repo. At some point we decided to switch to GPLv3 for all sources, if all authors/maintainers agree.

[dcanelhas]

I guess that's up to them, my contributions to the stack are available from my private repo under conditions that I consider reasonable enough.

This issue is regarding the license under which the public repo is currently made available. As far as I can tell, it does not mention GPL with all other references pointing to a less restrictive BSD license.

Even if future releases are published under GPLv3, it would be hard to argue that those conditions would apply retroactively to previous versions / forks of the repository.

[tstoyanov]

So, originally back in the day when we set up the first release of this stack, we followed the prefered guideline at the time and added a BSD-3 license to all headers. I agree with Daniel that we cannot retroactively change that. If anyone wants to use a checkout with a BSD-3 license there is nothing to stop them. As the repo is going through some major overhaul and this particular strucutre will not be supported anymore, I will add a LICENSE file (BSD-3) here. I will also indicate that this code is at EOL and will point to the new public release, when @tkucner is done.

[tkucner]

Hi all!
Yesterday I sent an e-mail to (I hope) all of the contributors, but I will repeat it here just to be on the safe side:

Dear All,

Over the time the percpetion_oru package has grown in volume, what made it difficult to maintain. To address this issue, the package was split into four
parts:

• ndt_core - the basic functionalities
• ndt_tools - set of stable tools built on top of the packages
• ndt_experimentalt - untested, yet to be released set of tools
• graph_map - a SLAM toolkit using (among the others) NDT representation.

During the process of the perception_oru package division, it has become
apparent that some of the packages lack licences. To fix this issue, I suggest
copying solution used in the navigation_oru package(https://github.com/OrebroUni
versity/navigation_oru-release/blob/master/LICENSE). In this package, the
authors use Creative Commons Attribution-NonCommercial-ShareAlike 4.0
International License and add separate licences for individual cases. It would
be good to follow this pattern, however, instead of Creative Commons
Attribution-NonCommercial-ShareAlike, we might use Attribution + ShareAlike.
Such a licence will make our code more accessible to the industry.

We plan to release the packages in two weeks. To make this, we would have to get
your feedback by next Thursday (30.08.18). I would like to hear from you if you
agree with this solution or if there are any reasons this will not work for you.

I am looking forward to hearing from you.

Sincerely,
Tomasz Kucner