Research Request - Performant vp -> speeds with interpolation method

[tiffanychu90]

Complete the below when receiving a research request, and continue to add to this issue as you receive additional details and produce deliverables. Be sure to also add the appropriate project-level label to this issue (eg gtfs-rt, DLA).

Research Question

Single sentence description: Use dask.map_partitions method wherever possible to: (1) shapely.project vp along scheduled shape geometry, (2) find the nearest vp to each stop position, (3) find subseq vp, (4) interpolate stop arrival between 2 positions.

• Epic - Daskify RT segment speeds #592
• Research Request - use vehicle positions near stop as actual_stop_arrival #785
• build on initial performance improvements in Find vp nearest stop #933

Detailed description:
Handle common errors that might occur:

• Near origin or destination, if we can't select 2 points to interpolate between, these edge cases need to be handled.
• Expected monotonic pattern between stops (vp_idx and location_timestamp_local should be increasing....but it's possible to find the nearest vp that's outside of that) -> factor in direction so that don't select a vp that's traveling in the opposite direction

Data sources

• Cal-ITP data sources: vp_usable

Deliverables

Scripts