| angles {adehabitat} | R Documentation |
angles computes the turning angles (in radians) between
consecutive moves from an object of class traj. See examples
for a clearer definition.
angles(x, id = levels(x$id), burst = levels(x$burst),
date = NULL, slsp = c("remove", "missing"))
x |
an object of class traj |
id |
a character vector giving the identity of the animals for which the angles are to be computed |
burst |
a character vector giving the identity of the circuits for which
the angles are to be computed (see traj) |
date |
a vector of class POSIXct of length 2 (beginning, end)
delimiting the period of interest |
slsp |
a character string. If "remove", successive
relocations located at the same place are replaced by a single
relocation, allowing the computation of the angles. If
"missing", a missing value is returned for the angles when
successive relocations located at the same place. |
Returns a data frame with the following components:
id |
the identity of the animal |
x |
the x coordinate of the relocation at which the angle is computed |
y |
the y coordinate of the relocation at which the angle is computed |
date |
a vector of class POSIXct, giving the date at which
the relocation has been taken |
burst |
the id of the circuit (see help(traj)) |
angles |
the turning angles between the successive moves. |
The function angles is deprecated. The class ltraj
computes the turning angles automatically (see ltraj).
Clement Calenge clement.calenge@oncfs.gouv.fr
Turchin, P. (1998) Quantitative analysis of movement. Measuring and modeling population redistribution in animals and plants. Sunderland, Massachusetts: Sinauer Associates.
speed for computation of movement speeds,
traj for additional information about objects of
class traj
## Not run:
## loads an object of class "traj"
data(puechcirc)
puechcir <- ltraj2traj(puechcirc)
puechcir
## Gets a part of the trajectory of the wild boar named
## CH93 and draws it
## Also displays the turning angles
toto <- puechcir[2:5,]
plot(toto$x, toto$y, asp = 1, ylim = c(3158300, 3158550),
pch = 16,
main = "Turning angles between\nthree consecutive moves",
xlab="X", ylab="Y")
lines(toto$x, toto$y)
lines(c(toto$x[2], 700217.6),
c(toto$y[2], 3158310), lty=2)
lines(c(toto$x[3],700289),
c(toto$y[3],3158546), lty=2)
ang1x <- c(700234.8, 700231.9, 700231, 700233.7, 700238.8, 700243.2)
ang1y <- c(3158332, 3158336, 3158341, 3158347, 3158350, 3158350)
ang2x <- c(700283.3, 700278.8, 700275.4, 700272.4, 700271.2, 700271.6,
700274.7)
ang2y <- c(3158522, 3158522, 3158520, 3158517, 3158514, 3158508, 3158504)
lines(ang1x, ang1y)
lines(ang2x, ang2y)
text(700216.1, 3158349, expression(theta[1]), cex=2)
text(700247.7, 3158531, expression(theta[2]), cex=2)
text(c(700301, 700231), c(3158399, 3158487),
c("Beginning", "End"), pos=4)
## Computation of the turning angles with real data
## on wild boars
plot(puechcir)
ang <- angles(puechcir)
## The angles are in the column angles:
ang[1:4,]
## End(Not run)