Bring rich telemetry data to Trips Endpoint in order to improve accuracy of historical analysis

[quicklywilliam]

Is your feature request related to a problem? Please describe.

Currently, the Trips endpoint does not include full telemetry data including Accuracy, Heading and Speed data. This data is included in Agency via the Telemetry object. Without this additional data, analyzing trip data is limited to only using long/lat coordinate information. Adding the full data (particularly accuracy, heading and speed) would allow for much improved accuracy and a higher success rate, particularly when snapping route data to the road network.

Describe the solution you'd like

Bring full telemetry data to the Trips endpoint, either by replacing GeoJSON points with Telemetry objects or by adding the extra fields as properties in the GeoJSON.

Is this a breaking change

Not-breaking. If the fields were added as properties in the GeoJSON this could be phased in as an optional thing and eventually be made required.

Impacted Spec

• provider

Additional context

When cleaning up GPS data to remove erroneous points and snap it to the street grid, it is helpful to have these extra fields as inputs. An obvious implementation that is currently not possible would be to simply throw out points below a certain accuracy, or where heading data is suddenly missing or discontinuous. With slightly more complex approaches, such as a Kalman Filter, having additional inputs to weight on can improve the output. When training a predictive model, features based on heading and speed data perform can particularly well.

This issue supersedes #51, which requested accuracy data for the trips endpoint.

[schnuerle]

See notes from the WG call this week.

• Providers, is this possible? Speed, heading, accuracy
• Some could be captured without GPS accuracy
• Spin doesn’t save this currently
• Useful to cities to get speed with breadcrumbs from an operator compliance perspective, but also for infrastructure planning to see where speed is too low/high. DC compare corridor speed to bus speed. Baltimore uses radar gun for speed due to being unreliable.
• Is this possible to capture and save this, is it possible? Can be an optional field for cities to request.
• London wanted max speed reached per trip.
• What is real value for cities?
• Needs more exploring about what is possible, how accurate, who’s doing it. Then use cases for cities. Then how to implement in MDS.
• Spin will look, OMF can reach out to other operators.
• Utility from other operators (Ride Report created this discussion)
• Note PR #73brings this up and adds altitude, vertical/horizontal accuracy.

[quicklywilliam]

Based on the conversation today, I've edited this issue to focus only on the use case of improving the accuracy of historical analysis of route data. This really only applies to the trips endpoint, so I've removed the language requesting equivalent changes to /status.

I've filed #616 to track possible changes to /status, based on the possible use case of wanting to assess compliance with speed-related rules. We see improving historical analysis as the more urgent and pressing use case, but if others are seeing important regulatory use cases please chime in on that issue!

[schnuerle]

For some more context, here is what is currently supported in Agency. Note the requirements are all listed as "Required if Available" from the provider.

https://github.com/openmobilityfoundation/mobility-data-specification/tree/release-1.1.0/agency#telemetry-data

Name	Type	Required?	Description
gps.lat	Double	Required	Latitude of the location
gps.lng	Double	Required	Longitude of the location
gps.altitude	Double	Required if Available	Altitude above mean sea level in meters
gps.heading	Double	Required if Available	Degrees - clockwise starting at 0 degrees at true North
gps.speed	Float	Required if Available	Speed in meters / sec
gps.accuracy	Float	Required if Available	Accuracy in meters
gps.hdop	Float	Required if Available	Horizontal GPS or GNSS accuracy value (see hdop)
gps.satellites	Integer	Required if Available	Number of GPS or GNSS satellites

[schnuerle]

We'll be talking about this at today's Working Group meeting.

[schnuerle]

Does anyone feel comfortable making a pull request for this, adding the Required if Available fields and others discussed to Provider Trips? There is a PR #73 but I think it's out of date (and the CLA needs to be signed).

[quicklywilliam]

Addressed by #653.