Depricating apt.dat and using Navigraph for scenery builds

[Johan G]

Split off from the topic GPL vs. CC licenses for development. Quote added for context.

[...] i see not a problem that we use 3th party data for navaids database e.g. navigraph this is allow in the gpl so long if the user install or allow by the provider in this case navigraph.
This mean is that linux distribution need to have a flightgear-navdata-nonfree pagacket or flightgear ask user with navigaton database the user wand to use include the advantage/disadvantage each option.
When a user select navigrave demo file than flightgear download the demo file form ower server or from navigraph else use the current building data.
Beside this there is also option for loading a newer navdatabase from navigraph for the users that have a navigraph account.
The only problem with this is that on each change of navigation database there is a rebuild of the scenery but this is easy to do as a overlay.
This is also a good idea to depricade the navigation database (nav.dat) from the scenery builds.
I see there are more problems if re going on this route.

I don't know the exact specifics of nav.dat but FlightGear only uses data that is or was freely available. There was one package, however, which was closed later on (which could be the source for nav.dat). But since we never re-synced with the non free data there is no need to call it non-free. It was free and therefore still is free data.

[Johan G]

I see there are more problems if re going on this route.

Indeed there are.

[...] i see not a problem that we use 3th party data for navaids database e.g. navigraph this is allow in the gpl so long if the user install or allow by the provider in this case navigraph. This mean is that linux distribution need to have a flightgear-navdata-nonfree pagacket or flightgear ask user with navigaton database the user wand to use include the advantage/disadvantage each option.

I do not think you had thought that fully through and more or less was brainstorming. Correct me if I am wrong but I think you went with the assumption that Navigraph would allow us or perhaps sell us rights to use their data for world builds and for the airport and navigation aid data bases. I think that would be very unlikely.

When a user select navigrave demo file than flightgear download the demo file form ower server or from navigraph else use the current building data.
Beside this there is also option for loading a newer navdatabase from navigraph for the users that have a navigraph account.
The only problem with this is that on each change of navigation database there is a rebuild of the scenery but this is easy to do as a overlay.

There are two big issues here, the world build and the licensing. Even on a powerful server the last world build literally took months to complete. While the next scenery build will use more powerful computers, it will also use way more data.

The licensing will not allow that happen though. The Navigraph Terms of Service makes it abundantly clear that the Navigraph data can not be shared and that Jeppesen retain all the rights to the data.

Navigraph terms of service:

3.1. License
When your purchase a subscription for the Navigraph Service we grant you a personal, revocable, non-exclusive, non-transferable, non-assignable, time-limited, worldwide license to use the Data without the right to copy, modify, publish, sub-license, disseminate and otherwise exploit the Data for any other Purpose and on any Technical Platform other than what is described in these Terms.

3.2. Additional Terms
The Data is provided by Jeppesen who is the owner and authorized licensor and therefore reserves all rights to the Data. For this reason you must also agree to the Jeppesen’s Additional Terms attached to these Terms.

Appendix 1 Jeppesen's Additional Terms for Jeppesen Data:

3. RESTRICTIONS ON USE. The Products may not be used for any other purpose, nor be sold or given by End-User to any third party for any use. Use of the Data by End-User to generate aviation charts or maps, whether for reference only or actual air navigation, is expressly prohibited. The Products cannot be used for performance based navigation procedure design (RNAV-RNP). End-User will NOT: (a) copy, reproduce, reverse engineer, decompile, disassemble or publish the Data; (b) electronically transfer the Products to multiple computers over a network system; (c) distribute copies of the Products or accompanying materials to others; (d) modify, adapt, or translate the Products or create derivative works based on the Products; or (e) assign, rent, lend, sell, transfer or sublease the Products.

This is also a good idea to depricade the navigation database (nav.dat) from the scenery builds.

If we have free data (even though it is outdated) it is still better than having users subscribe to Navigraph to be able to even find an airport. The cheapest subscription is around 30 EUR per year.

[www2]

@erik
I mean the fligtgear-nonfree package is for dataset for navigraph demo data not our own dataset that is current in fgdata.

@Johan G
The idea that i have have is that we ignore nav.dat at scenery building time and move to first time loading of flightgear and eatch change of navigation/scenery data(out side terrasync).
The resolute scenery are use as a overlay for the world scenery and add-ons scenery.
This can be done directly from navigraph database it self or post process this on the user computer.

Beside this i know that navigraph allow a outdate dataset include in eatch product as a demo for example littlenavmap use AIRAC cycle 1801 as there demo file.
And i have done some test to compare navigraph dataset and our dataset the difference between nav aids (vor/ndb/ils/etc) are not more than a vew meters and even i have check the ILS-cat-III for rwn 06 at EHAM the distence is not more than 4.78 cm between our data and navigraph.

[CaptB]

Some AIPs publish this data and it's available freely on their websites, it is possible to compile such file from that data. On the Danish AIP, whith which I'm most familiar for instance, I couldn't find copyright information, so I am not sure what is their position on it's usage, and under which license would it be possible to release such file.

[www2]

To my last post in this thread.
This is a part of a bigger project that i have in mind for a rewrite the navigation subsystem.
And some of the plans that i have is modeling HF/VHF/UHF com and nav radios, add support for GNSS systems as GPS/Galieo/Glonass.
Other object that i plan for this project is documenting and mapping some missing information about ICAO regions code for Australia, Brazil, Canada, Chile, Mainland China, Indonesia, Russia, United States.