Converts the ping-level trajectory of extracted trips into a table shaped
like the GTFS shapes.txt file: one shape per trip, points in travel
order, with cumulative distance. Unlike planned shapes, these traces record
the geometry actually driven, including detours.
Usage
g2g_shapes_from_trips(trajectory, shape_id_prefix = "SHP_")
Arguments
- trajectory
A data.table of trajectory GPS records with columns
trip_id, latitude, longitude, date,
time_str (as returned in the pipeline's $trajectory).
- shape_id_prefix
Character prefix for generated shape ids. Default
"SHP_" (shape ids become SHP_<trip_id>).
Value
A data.table with GTFS-standard columns shape_id,
shape_pt_lat, shape_pt_lon, shape_pt_sequence,
shape_dist_traveled (meters).
Details
Obtain the trajectory by running
g2g_extract_trips_and_stop_times(..., return_trajectory = TRUE) and
using the $trajectory element of the result.