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A statistical graphic designed for the archaeological study of when events of a specified kind occurred.

Usage

occurrence(object, ...)

# S4 method for EventsMCMC
occurrence(object, interval = c("ci", "hpdi"), level = 0.95)

# S4 method for OccurrenceEvents
autoplot(object, ..., colour = "black")

# S4 method for OccurrenceEvents,missing
plot(x, colour = "black", ...)

Arguments

object

An EventsMCMC object.

...

Currently not used.

interval

A character string specifying the confidence interval to be drawn. It must be one of "ci" (credible interval; the default) or "hpdi" (highest posterior density interval). Any unambiguous substring can be given.

level

A length-one numeric vector giving the confidence level.

colour

A character string specifying the colour of the segments.

x

An OccurrenceEvents object.

Value

  • occurrence() returns an OccurrenceEvents 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).

An OccurrenceEvents object.

Details

If we have \(k\) events, then we can estimate the calendar date \(t\) corresponding to the smallest date such that the number of events observed before \(t\) is equal to \(k\).

The occurrence() estimates these occurrences and gives the credible interval or the highest posterior density (HPD) region for a given level of confidence.

See also

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

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, ]

## Occurrence plot
occ_ci <- occurrence(eve, interval = "ci")
plot(occ_ci)


occ_hpdi <- occurrence(eve, interval = "hpdi")
plot(occ_hpdi)