Tempo Plot

A statistical graphic designed for the archaeological study of rhythms of the long term that embodies a theory of archaeological evidence for the occurrence of events.

tempo(object, ...)

# S4 method for class 'CumulativeEvents,missing'
plot(
  x,
  calendar = getOption("ArchaeoPhases.calendar"),
  interval = c("credible", "gauss"),
  col.tempo = "#004488",
  col.interval = "grey",
  main = NULL,
  sub = NULL,
  ann = graphics::par("ann"),
  axes = TRUE,
  frame.plot = axes,
  panel.first = NULL,
  panel.last = NULL,
  ...
)

# S4 method for class 'EventsMCMC'
tempo(
  object,
  level = 0.95,
  count = FALSE,
  credible = TRUE,
  gauss = TRUE,
  from = min(object),
  to = max(object),
  grid = getOption("ArchaeoPhases.grid")
)

Arguments

object: An EventsMCMC object.
...: Other graphical parameters may also be passed as arguments to this function.
x: A CumulativeEvents object or an EventsMCMC object.
calendar: A aion::TimeScale object specifying the target calendar (see calendar()).
interval: A character string specifying the confidence interval to be drawn. It must be one of "credible" (credible interval) or "gauss" (Gaussian approximation of the credible interval). Any unambiguous substring can be given.
col.tempo, col.interval: A specification for the plotting colors.
main: A character string giving a main title for the plot.
sub: A character string giving a subtitle for the plot.
ann: A logical scalar: should the default annotation (title and x and y axis labels) appear on the plot?
axes: A logical scalar: should axes be drawn on the plot?
frame.plot: A logical scalar: should a box be drawn around the plot?
panel.first: An an expression to be evaluated after the plot axes are set up but before any plotting takes place. This can be useful for drawing background grids.
panel.last: An expression to be evaluated after plotting has taken place but before the axes, title and box are added.
level: A length-one numeric vector giving the confidence level.
count: A logical scalar: should the counting process be a number or a probability (the default)?
credible: A logical scalar: should the credible interval be computed/displayed?
gauss: A logical scalar: should the Gaussian approximation of the credible interval be computed/displayed?
from: A length-one numeric vector giving the earliest date to estimate for (in years).
to: A length-one numeric vector giving the latest date to estimate for (in years).
grid: A length-one numeric vector specifying the number of equally spaced points of the temporal grid.

Value

tempo() returns an CumulativeEvents object.
plot() is called it for its side-effects: it results in a graphic being displayed (invisibly returns x).

Details

The tempo plot is one way to measure change over time: it estimates the cumulative occurrence of archaeological events in a Bayesian calibration. The tempo plot yields a graphic where the slope of the plot directly reflects the pace of change: a period of rapid change yields a steep slope and a period of slow change yields a gentle slope. When there is no change, the plot is horizontal. When change is instantaneous, the plot is vertical.

References

Dye, T. S. (2016). Long-term rhythms in the development of Hawaiian social stratification. Journal of Archaeological Science, 71: 1-9. doi:10.1016/j.jas.2016.05.006 .

Author

A. Philippe, M.-A. Vibet, T. S. Dye, N. Frerebeau

Examples

## Coerce to MCMC
eve <- as_events(mcmc_events, calendar = CE(), iteration = 1)
eve <- eve[1:10000, ]

## Tempo plot
tmp <- tempo(eve)
plot(tmp)

plot(tmp, interval = "credible", panel.first = grid())

plot(tmp, interval = "gauss", panel.first = grid())


## Activity plot
act <- activity(tmp)
plot(act, panel.first = grid())