Clean a move2 object using McConnell's algorithm — tt_clean

This function cleans a move2 object using McConnell's algorithm. It removes outliers based on the distance between consecutive points and the time interval between them (more explanation; give reference TODO). This function returns a clean move2 object; to generate a column that flags events to remove but does not remove them, use event_flag_mcconnell().

Usage

tt_clean_mcconnell(
  x,
  max_speed = NULL,
  flag_action = c("remove", "interpolate", "null"),
  check_first_last = FALSE
)

Arguments

x: A move2 object
max_speed: speed, provided as a units object (e.g. as_units(50, 'm/s').
flag_action: One of "remove", "null", or "interpolate", to either remove the points flagged by the algorithm, keep the time stamp but set location to NULL, or replace the location with a linearly interpolated location from the events that were not filtered out.
check_first_last: Logical. If TRUE, also evaluate the first and last currently valid point of each track using the endpoint RMS described above. If either endpoint is removed, the McConnell filter is rerun on the reduced track until the result is stable.

Value

A clean move2 object with events removed

Examples

# this removes 3 events from the example dataset
tt_clean_mcconnell(example_tt,
  max_speed = as_units(50, "km/h"),
  flag_action = "remove"
)
#> A <move2> with `track_id_column` "track_id" and `time_column` "date_time"
#> Containing 3 tracks lasting on average 1.33 hours in a
#> Simple feature collection with 12 features and 2 fields
#> Geometry type: POINT
#> Dimension:     XY
#> Bounding box:  xmin: -5.5053 ymin: -1.9431 xmax: 5.5357 ymax: 3.5288
#> Geodetic CRS:  WGS 84
#> First 10 features:
#>    track_id           date_time                geometry
#> 1         a 2024-01-01 12:00:00   POINT (1.371 -0.0627)
#> 2         a 2024-01-01 12:20:00   POINT (1.1694 3.5288)
#> 4         a 2024-01-01 13:00:00   POINT (3.6119 2.3638)
#> 5         a 2024-01-01 13:20:00  POINT (5.5357 -0.5769)
#> 6         b 2024-01-01 12:00:00 POINT (-2.4405 -1.7632)
#> 7         b 2024-01-01 12:20:00  POINT (-1.427 -1.9431)
#> 9         b 2024-01-01 13:00:00 POINT (-0.2703 -0.3566)
#> 10        b 2024-01-01 13:20:00 POINT (-0.9581 -1.5686)
#> 11        c 2024-01-01 12:00:00  POINT (-0.7845 0.4328)
#> 12        c 2024-01-01 12:20:00  POINT (-4.0496 1.0655)
#> Track features:
#>   track_id    sex nest_lon nest_lat
#> 1        a   male     1.37     0.06
#> 2        b   male    -2.44    -1.76
#> 3        c female    -0.78     0.43