rcarbon (version 1.5.1)

uncalibrate: Uncalibrate (back-calibrate) a calibrated radiocarbon date (or summed probability distribution).

Description

Function for uncalibrating one or more radiocarbon dates.

Usage

uncalibrate(x, ...)
# S3 method for default
uncalibrate(x, CRAerrors = 0, roundyear = TRUE, calCurves = "intcal20", ...)
# S3 method for CalGrid
uncalibrate(
  x,
  calCurves = "intcal20",
  eps = 1e-05,
  compact = TRUE,
  verbose = TRUE,
  ...
)

Value

A data.frame with specifying the original data, the uncalibrated age without the calibration curve error (ccCRA), the calibration curve error at this point in the curve (ccError), a randomised uncalibrated age (rCRA) given both the stated ccError and any further hypothesised instrumental error provided by the CRAerrors argument (rError).

Arguments

x

Either a vector of calibrated radiocarbon ages or an object of class CalGrid.

...

ignored

CRAerrors

A vector of standard deviations corresponding to each estimated radiocarbon age (ignored if x is a CalGrid object).

roundyear

Whether the randomised estimate is rounded or not. Default is TRUE.

calCurves

A string naming a calibration curve already provided with the rcarbon package (currently 'intcal20','intcal13','intcal13nhpine16','shcal20','shcal13','shcal13shkauri16',''marine13','marine20' and 'normal') or a custom curve provided as matrix/data.frame in three columns ("CALBP","C14BP","Error"). The default is the 'intcal20' curve and only one curve can currently be specified for all dates.

eps

Cut-off value for density calculation (for CalGrid objects only).

compact

A logical variable indicating whether only uncalibrated ages with non-zero probabilities should be returned (for CalGrid objects only).

verbose

A logical variable indicating whether extra information on progress should be reported (for CalGrid objects only).

Details

This function takes one or more calibrated calendars and looks-up the corresponding uncalibrated age, error of the stated calibration curve at that point. It also provides a randomised estimate of the uncalibrate age based on the curve error (and optionally also a hypothetical measurement error.

Examples

# Uncalibrate two calendar dates
uncalibrate(c(3050,2950))