Methods to work with a track. Function to calculate the absolute direction of a movement track. 0 is north.
velocity(x, ...)# S3 method for track_xyt
velocity(x, ...)
nsd(x, ...)
# S3 method for track_xy
nsd(x, ...)
diff_x(x, ...)
# S3 method for track_xy
diff_x(x, ...)
diff_y(x, ...)
# S3 method for track_xy
diff_y(x, ...)
A track_xyt.
Further arguments, none implemented.