rtrack: Generate random 'Track', 'Tracks' or 'TracksCollection'...

In trajectories: Classes and Methods for Trajectory Data

Generate random Track, Tracks or TracksCollection objects

Description

Generate random Track, Tracks or TracksCollection objects

Usage

rTrack(n = 100, origin = c(0,0), start = as.POSIXct("1970-01-01"), ar = .8, 
	step = 60, sd0 = 1, bbox = bbox, transform = FALSE, nrandom = FALSE, ...)
rTracks(m = 20, start = as.POSIXct("1970-01-01"), delta = 7200, sd1 = 0, 
	origin = c(0,0), ...)
rTracksCollection(p = 10, sd2 = 0, ...)

Arguments

n	number of points per Track
origin	numeric, length two, indicating the origin of the Track
start	POSIXct, indicating the start time of the Track
ar	numeric vector, indicating the amound of correlation in the Track
step	numeric; time step(s) in seconds between Track fixes
sd0	standard deviation of the random steps in a Track
sd1	standard deviation of the consecutive Track origin values (using rnorm)
sd2	standard deviation of the consecutive Tracks origin values (using rnorm)
bbox	bbox object FIXME:fill in
transform	logical; FIXME:fill in
nrandom	logical; if TRUE, draw n from rpois(n)
...	rTrack: arguments passed on to arima.sim, rTracks: arguments passed on to rTrack; rTracksCollection: arguments passed on to rTracks
m	number of Track objects to simulate
delta	time difference between consecutive Track start times
p	number of IDs with Tracks to generate

Details

ar is passed on to arima.sim as ar element, and may contain multiple AR coefficients. The generated track is a cumsum over the simulated AR values, for each dimension. In case it has length 1 and value 0, random walk is created using rnorm. If bbox is given, the generated track will be transformed to bbox. If transform is TRUE and no bbox is given, it transforms the track to a unit box. If nrandom is TRUE, it generates a random number using rpois with parameter n as the number of locations per track.

Value

An object of class Track, Tracks or TracksCollection.

Author(s)

Edzer Pebesma <[e-mail]>, Mohammad Mehdi Moradi <[e-mail]>

Examples

x = rTrack()
dim(x)
plot(x)
# x = rTracks(sd1 = 120)
# dim(x)
# plot(as(x, "SpatialLines"), col = 1:dim(x)[1], axes=TRUE)
# x = rTracksCollection() # star
# dim(x)
# plot(x)
x = rTracksCollection(sd2 = 200,p=4,m=10)
plot(x, col=1:dim(x)[1])

trajectories documentation built on Sept. 11, 2024, 8:48 p.m.