Dice distance matrix
Computes a distance derived from Dice's coincidence index between the columns of a 0-1-matrix.
dicedist(regmat)
regmat |
0-1-matrix. Columns are species, rows are regions. |
The Dice distance between two species is 1 minus the Coincidence Index, which is (2*number of regions where both species are present)/(2*number of regions where both species are present plus number of regions where at least one species is present). This is S23 in Shi (1993).
A symmetrical matrix of Dice distances.
Shi, G. R. (1993) Multivariate data analysis in palaeoecology and palaeobiogeography - a review. Palaeogeography, Palaeoclimatology, Palaeoecology 105, 199-234.
options(digits=4) data(kykladspecreg) dicedist(t(kykladspecreg))
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