trajr (version 1.5.1)

plot.TrajSpeedIntervals: Plot method for trajectory speed intervals

Description

Plots speed over time, with intervals of fast and/or slow speed highlighted.

Usage

# S3 method for TrajSpeedIntervals
plot(
  x,
  slowerThanColour = "red",
  fasterThanColour = "green",
  highlightColor = "#0000FF1E",
  xlab = sprintf("Time (%s)", TrajGetTimeUnits(attr(x, "trajectory"))),
  ylab = sprintf("Speed (%s/%s)", TrajGetUnits(attr(x, "trajectory")),
    TrajGetTimeUnits(attr(x, "trajectory"))),
  type = "l",
  ...
)

Arguments

x

An object of class "SpeedIntervals", as created by TrajSpeedIntervals.

slowerThanColour, fasterThanColour

The colour of the horizontal line plotted at the "slower than" or "faster than" speed. Specify NULL to prevent the line from being plotted.

highlightColor

Colour of the highlight rectangles.

xlab, ylab, type

Plotting parameters with useful defaults.

...

Additional arguments are passed to plot.

See Also

TrajSpeedIntervals

Examples

# Display speed intervals with custom x-axis labels

# Generate and smooth a trajectory
set.seed(3)
trj <- TrajSmoothSG(TrajGenerate(120, fps = 0.5))
# Get speed intervals to be plotted
si <- TrajSpeedIntervals(trj, slowerThan = 0.9, diff = "central")
# Plot, but don't label x axis
plot(si, xlab = "Time (min:sec)", xaxt = "n")
# Work out where x-axis tick marks should be
speeds <- attr(si, "speed") # data frame containing speed over time
p <- pretty(speeds$time)
# Draw x-sxis ticks and labels with custom formatting
axis(1, p, sprintf("%d:%02d", p %/% 60, p %% 60))