Description Usage Arguments Value Examples
simulate from the rw
, crw
of mpm
process models
to generate a set of x,y (or lon,lat) coordinates with or without error from
supplied input parameters.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | sim(
N = 100,
start = list(c(0, 0), as.POSIXct(format(Sys.time(), tz = "UTC", usetz = TRUE))),
model = c("rw", "crw", "mpm"),
vmax = 4,
sigma = c(4, 4),
rho_p = 0,
D = 0.05,
sigma_g = 1.25,
error = c("ls", "kf"),
tau = c(1.5, 0.75),
rho_o = 0,
tdist = c("reg", "gamma"),
ts = 3,
tpar = c(0.23, 1),
alpha = c(0.9, 0.8)
)
|
N |
number of time steps to simulate |
start |
coordinates and datetime of start location for simulated track |
model |
simulate from the |
vmax |
maximum travel rate (m/s) of simulated animal |
sigma |
a vector of process error sd's for the |
rho_p |
correlation parameter for |
D |
diffusion coefficient for |
sigma_g |
random walk sd for time-varying move persistence parameter
(ignored if |
error |
indicates whether measurement error should mimic Argos Least-Squares ("ls") or Argos Kalman Filter ("kf") |
tau |
vector of LS measurement error sd's (ignored if |
rho_o |
correlation parameter for LS covariance matrix
(ignored if |
tdist |
distribution for simulating location times ("reg" generates locations at regular ts intervals, in h; "gamma" uses a gamma distribution to generate random time intervals) |
ts |
time interval in h (ignored if |
tpar |
shape and scale parameters for the gamma distributed times
(ignored if |
alpha |
transition probabilities switching model versions of
|
a tibble is returned with columns that can include some or all of the following, depending on the arguments used
date |
time as POSIXct tz = UTC (default) |
lc |
Argos location class |
lon |
longitude with error |
lat |
latitude with error |
x |
x in km from arbitrary origin without error |
y |
y in km from arbitrary origin without error |
x.err |
a random deviate drawn from Argos LS or KF error distribution |
y.err |
a random deviate drawn from Argos LS or KF error distribution |
smaj |
Argos error ellipse semi-major axis in m (if error = "kf") |
smin |
Argos error ellipse semi-minor axis in m (if error = "kf") |
eor |
Argos error ellipse orientation in degrees (if error = "kf") |
u |
velocity in x direction (if model = "crw") |
v |
velocity in y direction (if model = "crw") |
b |
behavioural state (if model = "rw" or "crw" and multiple process variances given, see examples) |
g |
movement persistence - the autocorrelation between successive movements on the interval 0,1 (if model = "mpm") |
1 2 3 4 5 6 7 8 9 10 11 12 | tr <- sim(N = 200, model = "crw", D = 0.1, error = "kf", tdist = "reg", ts=12)
plot(tr, error = TRUE)
tr <- sim(N = 200, model = "rw", sigma = c(4,4,0.5,0.5), error = "ls", tdist = "reg")
plot(tr)
tr <- sim(N = 200, model = "crw", D = c(0.1, 0.05), error = "kf", tdist="reg")
plot(tr)
tr <- sim(N = 200, model = "mpm", sigma_g = 1.2, error = "ls", tau = c(2, 1.5),
tdist = "gamma", tpar = c(1, 4))
plot(tr, error = TRUE, pal = "Cividis")
|
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