TransmitterDan what an awesome offer!
I'd like to help in whatever way possible.
I believe the original philosophy was Dashboard would only show the Nmea data stream and not "create" missing data. However for a Sailing Console and TacknLay we are finding that we need certain data that can be calculated for the plugins to work.
A. Those plugins themselves could do the calcs.
B. As you suggested an intermediate "Derived Data" plugin could provide the calcs.
C. Dashboard could do the calcs and show the data and optionally inject into the nmea data stream, provided the data was shown in a different color, as "derived".
Paul Elliot's NavMonPC is pretty good about data priority and options for calculation, it is worth a look at how he does it. Also I found a good pdf about NavMonPc data priorities that is worth reviewing whatever is decided.
I think the goals should be
1. To keep it simple and reliable for the user, with good instructions -but hopefully unnecessary.
2. Provide the data needed for motor
and/or sail console in a useful format without too much real estate (size adjustible?)
3. Automatically sense if some data is not there, and prompt if you want it calculated (if possible)? Or some other kind of approach.
4. Try to consolidate information when possible and possible improve graphics.
5. Remove older unnecessary instruments possibly.