adehabitat (version 1.8.20)

speed: Computes the Speed Between Successive Relocations of an Animal - Deprecated

Description

speed measures the speed between successive relocations of animals, using objects of class traj.

Usage

speed(x, id = levels(x$id), burst = levels(x$burst), date = NULL,
      units = c("seconds", "hours", "days"))

Arguments

x

an object of class traj

id

a character vector giving the identity of the animals for which the speed is to be computed

burst

a character vector giving the identity of the circuits for which the speed is to be computed (see traj)

date

a vector of class POSIXct of length 2 (beginning, end) delimiting the period of interest

units

a character string. It determines how the speeds are computed. For example, if the coordinates are given in meters, and if units = "seconds", speeds are returned in meters per second.

Value

Returns a data frame with the following components:

id

the identity of the animal

x

if the speed is computed between the relocation 1 and 2, the x coordinate of the relocation 1.

y

if the speed is computed between the relocation 1 and 2, the y coordinate of the relocation 1.

date

a vector of class POSIXct, giving the date of relocation 1.

burst

the identity of the circuit

sp.x

the computed speed of the animal in the x direction

sp.y

the computed speed of the animal in the y direction

speed

the computed speed of the animal on the plane.

dt

the duration between the two relocations (in the units given by the parameter units).

See Also

traj

Examples

# NOT RUN {
#### Computes the speed for each wild boar
#### monitored at Puechabon
data(puechcirc)
puechcirc <- ltraj2traj(puechcirc)
puechcirc

plot(puechcirc)
sp <- speed(puechcirc)
sp[1:4,]
# }