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Calculate correlation values between tree-ring series

Source: R/cor_table.R
cor_table.Rd

Deprecated: cor_table() is deprecated as of fellingdater version 1.2.0 Please use trs_crossdate() instead.

This function calculates common correlation values between dated tree-ring series (x) and a set of reference chronologies (y). When no master chronologies are provided, each series in x is compared to all other series in x.

Only values are reported for pairs of series with a common overlap >= min_overlap.

The correlation values computed include:

  • glk: 'Gleichläufigkeit' or 'percentage of parallel variation' (Buras & Wilmking 2015; Eckstein & Bauch 1969; Huber 1942; Visser 2020)

  • glk_p: significance level associated with the glk-value (Jansma 1995)

  • r_pearson: the Pearson's correlation coefficient

  • t_St: Student's t-value

  • t_BP: t-values according to the Baillie & Pilcher (1973) algorithm

  • t_Ho: t-values according to the Hollstein (1980) algorithm

Usage

cor_table(
  x,
  y = NULL,
  min_overlap = 50,
  remove_duplicates = TRUE,
  output = "table",
  sort_by = "t_Ho"
)

Arguments

x

A data.frame of class ´rwl' with tree-ring data. Each column represents a measurement series, and row names correspond to (calendar) years.

y

A data.frame of class 'rwl' with tree-ring data. Each column represents a measurement series or chronology, and row names correspond to (calendar) years. If NULL (default), x is compared to itself (y = x).

min_overlap

A numeric value specifying the minimum overlap required between series for correlation calculation.

remove_duplicates

A logical value. If TRUE, identical pairs of series and references are removed from the output.

output

The desired output format, either "matrix" or "table" (default).

sort_by

The correlation value by which the output is sorted for each series in x. One of "r_pearson", "t_St", "glk", "glk_p", "t_BP", "t_Ho". Default to "t_Ho"

Value

The function returns a list of correlation matrices if output is set to "matrix." If output is set to "table," it returns a data.frame reporting all correlation values.

Details

This function computes various correlation values between tree-ring series in a data.frame x and a set of reference chronologies in a data.frame y. If y is not provided, it compares each series in x to all other series in `x.

References

  • Baillie, M.G.L., Pilcher, J.R. (1973) A simple crossdating program for tree-ring research. Tree-Ring Bulletin 33, 7–14. http://hdl.handle.net/10150/260029

  • Buras, A. and Wilmking, M. (2015) Correcting the calculation of Gleichläufigkeit, Dendrochronologia 34, 29-30. https://doi.org/10.1016/j.dendro.2015.03.003

  • Eckstein, D. and Bauch, J. (1969) Beitrag zur Rationalisierung eines dendrochronologischen Verfahrens und zur Analyse seiner Aussagesicherheit. Forstwissenschaftliches Centralblatt, 88(1), 230-250.

  • Huber, B. (1943) Über die Sicherheit jahrringchronologischer Datierung. Holz als Roh- und Werkstoff 6, 263-268. https://doi.org/10.1007/BF02603303

  • Hollstein E. (1980) Mitteleuropäische Eichenchronologie. Trierer dendrochronologische Forschungen zur Archäologie und Kunstgeschichte, Trierer Grabungen und Forschungen 11, Mainz am Rhein.

  • Jansma, E. (1995) RemembeRINGs; The development and application of local and regional tree-ring chronologies of oak for the purposes of archaeological and historical research in the Netherlands, Nederlandse Archeologische Rapporten 19, Rijksdienst voor het Oudheidkundig Bodemonderzoek, Amersfoort. https://dspace.library.uu.nl/handle/1874/45149

  • Schweingruber, F. H. (1988) Tree rings: basics and applications of dendrochronology, Kluwer Academic Publishers, Dordrecht, Netherlands, 276 p.

  • Visser, R.M. (2020) On the similarity of tree-ring patterns: Assessing the influence of semi-synchronous growth changes on the Gleichläufigkeit for big tree-ring data sets, Archaeometry 63, 204-215. https://doi.org/10.1111/arcm.12600

See also

trs_crossdate() for the function that replaces cor_table()).

Examples

# example code
if (FALSE) { # \dontrun{
Doel1 <- system.file("extdata", "DOEL1.fh", package = "fellingdater")
Doel1_trs <- read_fh(Doel1, verbose = FALSE)
# crossdating ring-width series from Doel 1 against each other:

cor_results <- cor_table(Doel1_trs,
     output = "table", min_overlap = 80,
     sort_by = "t_Ho", remove_duplicates = TRUE
)
head(cor_results, 20)
} # }