plot_joint_scat {cylcop}

Scatterplot of Turn Angles and Step Lengths

Description

This function produces a scatterplot ('ggplot' object) of the turn angles and step lengths.

Usage

plot_joint_scat(
  traj = NULL,
  theta = NULL,
  x = NULL,
  periodic = FALSE,
  plot_margins = FALSE
)

Arguments

traj

data.frame containing the trajectory produced by e.g. traj_sim(). It must contain the columns traj$angle and traj$steplength.

theta

(alternatively) numeric vector of angles (measurements of a circular variable).

x

(alternatively) numeric vector of step lengths (measurements of a linear variable).

periodic

logical value denoting whether the plot should be periodically extended past -pi and pi.

plot_margins

logical determining whether the marginal kernel density estimates are computed and plotted. Alternatively, plot_margins can be a list of length 2 containing first a kernel density estimate for theta and second a kernel density estimate for x. The first entry must be of type 'density.circular' (as returned e.g. by fit_angle(theta, parametric=FALSE)), and the second entry must be of type "density" (as returned e.g. by fit_steplength(x, parametric=FALSE)).

Details

You can either specify traj or the angels and step lengths (theta and x). If plot_margins=T, the code will attempt to find appropriate bandwidths for the kernel density estimate autonomously, also taking into account computational time. For more control over the actual method and parameters used to obtain the kernel density estimates, you can calculate them "by hand" using e.g. fit_angle(theta, parametric=FALSE) and fit_steplength(x, parametric=FALSE)).

Value

A 'ggplot' object, the scatterplot.

References

Hodel FH, Fieberg JR (2022). “Circular-Linear Copulae for Animal Movement Data.” Methods in Ecology and Evolution. doi:10.1111/2041-210X.13821.

Hodel FH, Fieberg JR (2021). “Cylcop: An R Package for Circular-Linear Copulae with Angular Symmetry.” bioRxiv. doi:10.1101/2021.07.14.452253, https://www.biorxiv.org/content/10.1101/2021.07.14.452253v3/.

See Also

plot_cop_scat(), plot_track(), plot_joint_circ(), plot_cop_surf().

Examples

set.seed(123)
traj <- traj_sim(100,
  copula = cyl_quadsec(0.1),
  marginal_circ = list(name = "vonmises", coef  = list(0, 1)),
  marginal_lin = list(name = "weibull", coef = list(shape = 3))
)

plot1 <- plot_joint_scat(traj)
plot2 <- plot_joint_scat(traj, periodic = TRUE)
plot3 <- plot_joint_scat(theta=traj$angle, x=traj$steplength, periodic = TRUE, plot_margins=TRUE)

bw <- opt_circ_bw(theta = traj$angle, method = "nrd",kappa.est = "trigmoments")
ang_dens <- fit_angle(theta=traj$angle, parametric=FALSE, bandwidth=bw)
step_dens <- fit_steplength(x=traj$steplength, parametric=FALSE)
plot4 <- plot_joint_scat(traj, periodic = TRUE, plot_margins=list(ang_dens, step_dens))