rice (version 1.1.1)

smooth.curve: Smooth a calibration curve

Description

Smooth a calibration curve over a time window of a specified width. This to accommodate material that has accumulated over a certain assumed time, e.g. a cm of peat over say 30 years.

Usage

smooth.ccurve(
  smooth = 30,
  cc = 1,
  postbomb = FALSE,
  cc.dir = c(),
  thiscurve = c(),
  resample = 0,
  name = "smoothed.csv",
  save = FALSE,
  sep = "\t"
)

Arguments

smooth

The window width of the smoothing. Defaults to smooth=30.

cc

The calibration curve to smooth. Calibration curve for 14C dates: 'cc=1' for IntCal20 (northern hemisphere terrestrial), 'cc=2' for Marine20 (marine), 'cc=3' for SHCal20 (southern hemisphere terrestrial). Alternatively, one can also write, e.g., "IntCal20", "Marine13". One can also make a custom-built calibration curve, e.g. using 'mix.ccurves()', and load this using 'cc=4'. In this case, it is recommended to place the custom calibration curve in its own directory, using 'cc.dir' (see below).

postbomb

Use 'postbomb=TRUE' to get a postbomb calibration curve (default 'postbomb=FALSE'). For monthly data, type e.g. 'ccurve("sh1-2_monthly")'

cc.dir

Directory of the calibration curves. Defaults to where the package's files are stored (system.file), but can be set to, e.g., 'cc.dir="ccurves"'.

thiscurve

As an alternative to providing cc and/or postbomb, the data of a specific curve can be provided (3 columns: cal BP, C14 age, error). Defaults to c().

resample

The IntCal curves come at a range of 'bin sizes'; every year from 0 to 5 kcal BP, then every 5 yr until 15 kcal BP, then every 10 yr until 25 kcal BP, and every 20 year thereafter. The curves can be resampled to constant bin sizes, e.g. 'resample=5'. Defaults to FALSE.

name

The filename of the curve, if it is being saved. Defaults to name="smoothed.csv".

save

Whether or not to save the curve to cc.dir. Defaults to save=FALSE.

sep

Separator between fields if the file is saved (tab by default, sep="\t").

Author

Maarten Blaauw

Details

The smoothing is done by calculating the mean C14 age and error of a moving window (moving along with the cal BP steps of the calibration curve). Something similar is done in the online calibration software CALIB.

Examples

 mycurve <- smooth.ccurve(smooth=50)
 calibrate(2450,20, thiscurve=mycurve)