Gets the relative heading between two track segments (three localizations)
using the law of cosines.
The turning angle is returned in degrees.
Adds the column angle to a data.table with tracking data.
Note that with smoothed data NaN values may occur (when subsequent
localizations are at the same place).
Usage
atl_turning_angle(data, tag = "tag", x = "x", y = "y", time = "time")
Arguments
- data
A dataframe or similar which must have the columns
specified by x, y, and time.
- tag
The tag ID.
- x
The x coordinate.
- y
The y coordinate.
- time
The timestamp in seconds since the UNIX epoch.
Value
A a data.table with added turning angles in degrees.
Negative degrees indicate 'left' turns. There are two fewer
angles than the number of rows in the dataframe.
Author
Pratik R. Gupte & Allert Bijleveld & Johannes Krietsch
Examples
if (FALSE) { # \dontrun{
data <- atl_turning_angle(
data,
tag = "tag", x = "x", y = "y", time = "time"
)
} # }
