This function calculates the matrix of Gleichläufigkeit for a given set of tree-ring records.
Gleichläufigkeit is a classical agreement
test based on sign tests (Eckstein and Bauch, 1969). This function
implements Gleichläufigkeit as the pairwise
comparison of all records in data set, and thus returns a matrix whose
upper triangle reports the Gleichläufigkeit
of each possible combination of records. The global
Gleichläufigkeit can be calculated as
mean(glk(x), na.rm = TRUE). This implementation improves
the original formulation inasmuch as the case of neighbouring
identical measurements in the same years is accounted for. Here, it is
treated as full agreement, in contrast to only partial agreement in
the original formulation.
matrix with the Gleichläufigkeit for
all possible combinations of records. If two curves have less than 3
years of overlap, Gleichläufigkeit cannot be
NA is returned.
Christian Zang. Patched and improved by Mikko Korpela. Improved by Allan Buras.
Eckstein, D. and Bauch, J. (1969) Beitrag zur Rationalisierung eines dendrochronologischen Verfahrens und zur Analyse seiner Aussagesicherheit. Forstwissenschaftliches Centralblatt, 88(1), 230–250.
Schweingruber, F. H. (1988) Tree rings: basics and applications of dendrochronology. Kluwer Academic Publishers, Dordrecht, Netherlands, 276 p.
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