Make Stop-Time Offsets Monotone — rt2s_monotone

Rounds travel and dwell offsets to integer seconds, clamps negative values to zero, and makes a stop pattern monotone with a forward pass.

Usage

rt2s_monotone_offsets(travel, dwell)

Arguments

travel: Numeric vector of arrival offsets from trip start, in seconds.
dwell: Numeric vector of dwell offsets, in seconds, with the same length as travel.

Value

A list with integer vectors arrival and departure. Each departure is its arrival plus its dwell, and each arrival is at least the previous departure.

Details

Inputs must be finite numeric vectors of equal length. Values are rounded with base::round() before negative values are clamped to zero. For each stop, the returned arrival is the larger of its clamped travel offset and the previous returned departure. This satisfies GTFS along-trip monotonicity even when independently estimated offsets are out of order.

Examples

rt2s_monotone_offsets(
  travel = c(-2.4, 300.6, 298.2),
  dwell = c(0, 30.6, 15)
)
#> $arrival
#> [1]   0 301 332
#> 
#> $departure
#> [1]   0 332 347
#>