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.

## Usage

tempo(object, ...)

# S4 method for EventsMCMC
tempo(
object,
level = 0.95,
count = FALSE,
credible = TRUE,
gauss = TRUE,
from = min(object),
to = max(object),
resolution = NULL
)

# S4 method for CumulativeEvents
autoplot(object, ..., credible = TRUE, gauss = TRUE)

# S4 method for CumulativeEvents,missing
plot(x, credible = TRUE, gauss = TRUE, ...)

# S4 method for CumulativeEvents
multiplot(...)

## Arguments

object

An EventsMCMC object.

...

Any CumulativeEvents object.

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).

resolution

A length-one numeric vector specifying the temporal resolution (in years) at which densities are to be estimated. If NULL (the default), equally spaced points will be used (according to options("chronos.grid")).

x

A CumulativeEvents object.

## Value

• tempo() returns an CumulativeEvents object.

• autoplot() and multiplot return a ggplot 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 .

Other event tools: activity(), occurrence(), rec, roc()

## Author

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

## Examples

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

## Tempo plot
tmp <- tempo(eve)
plot(tmp, credible = TRUE, gauss = FALSE)

plot(tmp, credible = FALSE, gauss = TRUE)

## Activity plot
act <- activity(tmp)
plot(act)