NED coordinates

[jleny]

Hi,

Would it make sense to add NED to this package in addition to ENU? North East Down is a more standard convention in aerospace engineering and that would make interfacing with some other projects smoother.

[c42f]

Technically this should be quite easy - you could add a NED type and NEDfromENU / ENUfromNED as simple permutations / sign change relative to ENU, and then all the other transformations would automatically be possible via composition. (some compositions could optionally be predefined for convenience)

I don't exactly love the proliferation of different coordinate types we have in this package but I also don't want to get too hung up on that. Do you think there's value in distinguishing between ENU and NED at the type level for your use cases?

[jleny]

Matlab's mapping toolbox has NED in addition to ENU, whereas the aerospace toolbox only seems to mention NED. I work on navigation systems, where NED is almost universally used over ENU.

There is no fundamental issue with implementing a NED type in higher-level applications every time it is needed, but I feel it would be more natural to have it here at the coordinate system level, on equal footing with ENU.

I was initially thinking of just duplicating all the ENU code, but indeed this could be done via composition if you prefer. If you want I can take a shot at it when I find some time.

[andyferris]

If you want I can take a shot at it when I find some time.

Yes, that would be great.