by Hooray » Sat May 04, 2019 1:08 pm
there are several points to keep in mind here:
the navcache/navdb is not a "proper" SGSubsystem in the FlightGear sense, when we were developing the MapStructure framework, we ended up wrapping the corresponding navdb APIs so that we could override those with our own - this was primarily to test with proprietary/external navdata, or online navdata sources
That being said, it would not be complicated to patch fgfs and totally disable the navdb. But what you probably want instead is a way to re-map those APIs to an alternate source, this is commonly achieved using scripted Nasal delegates, I believe the route manager uses that approach.
Finally, under the hood, it's really just an SQLite database, so if you should find the corresponding people unresponsive, you can simply use an SQLite editor to look at the DB and come up with a python script to create a matching file.
I do agree that this is not very elegant, but it would at least work "as is" - obviously, when it comes to runways, airports etc - there remains the issue of possibly mismatching terrain/scenery data.