Remove reflections, or prolonged spikes from a movement track by identifying
the bounds and removing positions between them.
The important function arguments here are point_angle_cutoff ($A$),
reflection_speed_cutoff ($S$).
If the prolonged spike ends before the last row of data, the true end point
is used as the outer bound of the spike.
If the prolonged spike does not end within the last row of data, all the
data are retained and a message is printed.
atl_remove_reflections( data, x = "x", y = "y", time = "time", point_angle_cutoff = 45, reflection_speed_cutoff = 20 )
| data | A dataframe or similar which has previously been cleaned. |
|---|---|
| x | The name of the X coordinate column. |
| y | The name of the Y coordinate column. |
| time | The name of the timestamp column. |
| point_angle_cutoff | The turning angle (in degrees) above which high instantaneous speeds are considered an anomaly rather than fast transit. |
| reflection_speed_cutoff | The speed (in m/s) above which an anomaly is detected when combined with a high turning angle. |
A dataframe with reflections removed.
Pratik R. Gupte
if (FALSE) { filtered_data <- atl_remove_reflections( data = track_data, x = "x", y = "y", time = "time", point_angle_cutoff = A, reflection_speed_cutoff = S ) }