prex {sdam}

Compute probabilities of existence

Description

A function to compute probabilities of existence of artefacts related events.

Usage

prex(x, type = c("aoristic", "mp", "other"), taq, tpq, vars, 
     bins = NULL, cp, weight = 1, DF, out, plot = FALSE, main = NULL, 
     ylim, keep, ...)

Arguments

x

list or data frame object of variables and observations.

type

Type of date format to compute or plot:

aoristic aoristic sum

mp mid points and range

other

taq

timespan endpoint terminus ante quem (TAQ)

tpq

timespan endpoint terminus post quem (TPQ)

vars

boundaries of existence of x (vector for timespan endpoints)

bins

length of the break (integer and optional)

cp

Chronological phase:

"bin5" five-bins from the antiquity period

"bin8" eight-bins from the antiquity period

list with a customized chronological phase

weight

value to observations (optional)

DF

return also data frame with observations? (optional and logical)

out

number of outliers to omit (integer or vector where first entry id for latest date)

plot

plot the results?

main

plot's main title (optional)

ylim

limit in y-axis (optional, for plot)

keep

for mp, keep variables in output? (optional and logical)

...

additional optional parameters

Details

Currently, the probability of existence of the observations is the aoristic sum computed across events for portions of time delimited by a TAQ in taq and TPQ in tpq, which are endpoints from the stance of the timespan. Alternatively, these two boundaries of existence of x are specified in vars.

In case the bins are set to NULL, then the time breaks take the chronological periods in cp, which by default is "bin5" or five-periods for the EDH dataset, which are Arch (Archaic), Class (Classical), Hell (Hellenistic), Rom, (Roman), and Byz (Byzantine). Another built-in option is "bin8" for eight chronological periods where the Roman period is divided into ERom (Early Roman), MRom (Middle Roman), and LRom (Late Roman) while the Byzantine period is divided into EByz (Early Byzantine) and MByz (Middle Byzantine). However, option cp is open for other periodization models as long as the categories of time blocks are components of a list object.

Value

A data frame with values according to the chosen either bins or cp. If plot is specified, a bar plot with bars of outcomes.

Note

When aoristic is set to FALSE, then a simple matching of only TAQ and TPQ is computed from x.

Author(s)

Antonio Rivero Ostoic

References

Crema, E. “Modelling temporal uncertainty in archaeological analysis,” J Archaeol Method Theory, 19:440–461. (2012). (for aoristic sum)

Bevan, et al. “Measuring chronological uncertainty in intensive survey finds: A case study from Antikythera, Greece,” Archaeometry, 55, 2, 312–328. (2013). (default chronological periods)

See Also

edhw, plot.dates, dts.

Examples

## Not run: 
# first 100 entries in the EDH dataset (default)
EDHdates <- edhw(vars=c("not_after", "not_before"), as="df", limit=100)

# compute aoristic sum with five-periods
prex(x=EDHdates, taq="not_before", tpq="not_after", cp="bin5")

# compute aoristic sum with 75 year span
prex(x=EDHdates, taq="not_before", tpq="not_after", bins=75, plot=TRUE)
## End(Not run)