Jaccard distance matrix
Computes Jaccard distances between the columns of a 0-1-matrix.
jaccard(regmat)
regmat |
0-1-matrix. Columns are species, rows are regions. |
The Jaccard distance between two species is 1-(number of regions where both species are present)/(number of regions where at least one species is present). As a similarity coefficient, this is S22 in Shi (1993).
Thank you to Laurent Buffat for improving this function!
A symmetrical matrix of Jaccard 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) jaccard(t(kykladspecreg))
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