Trips at identical locations oscillate priority

[remulasce]

If they're extremely close to each other, there may not be a consistent "closest" station, or if they are identical locations.

[remulasce]

Maybe add some priority based on order of addition?

[remulasce]

It's because proximity update times are not synced to location updates. So if you're moving closer to a stop, the most recently updated stop will always be closest, guaranteeing they fluctuate.

We should make it so that all proximities update at the same time. Preferably, right after we receive a location update.

[remulasce]

Labelling bug because design practically guarantees this.

[remulasce]

Proximity priority in general is a little screwed up actually.

[remulasce]

Let's get this out in dev_2 Dev_2 is basically 'nice release to line up with iOS port'

[remulasce]

Problem exacerbated by:

• Multiple identical stop locations
• Short GPS location interval
• Short proximity refresh interval
• Proximity-only trip priority

Note that the problem is the constant flip-flopping every couple seconds. Once a minute doesn't look bad, and remember these stops are supposed to change priority based on movement.

Outside impacts:

• Stop proximity calculations are resource-intensive currently, and they can cause visible jitter.
• Proximity update frequency needs to be high enough to put your destination stop above your origin stop by the time you get to it.
• GPS obviously impacts battery life.

Possible solutions:

• Synchronize all proximity priority calculations
• Increase the proximity check interval so it doesn't flip-flop as often
• Add some differentiating priority to Trips that keeps close stations in one order even as their proximities change

[remulasce]

For Immediate Implementation:

Synchronize proximity calculations

That gives us better control over GPS tuning as well, along with an avenue for better mock location testing.

Differentiating priority- like, first requests added get more priority- takes care of 2 birds, but it's more of a band-aid for this problem and requires tuning that's beyond the scope of this issue.

[remulasce]

Trip proximities are now synchronized. We get the current distance every update from the locationretriever Locationretriever has been given a cache, so it doesn't have to do those calculations every time.

When we get a new location, we update the whole cache with it at once, so everybody gets their proximity to the same location as long as they check every frame.