crosstab {ecodist}R Documentation

Data formatting

Description

Converts field data of the form site, species, observation into a matrix.

Usage

crosstab(rowlab, collab, values, type = "sum")

Arguments

rowlab row labels, e.g. site names.
collab column labels, e.g. species names.
values data values.
type function to use to combine data, one of "sum" (default), "min", "max", "mean".

Details

Field data are often recorded as a separate row for each site-species combination. This function turns them into a matrix for further analysis based on unique row and column labels.

The three vectors should all be the same length (including duplicates).

Value

matrix with rowlab as row headings, collab as columns, and values as the data.

Author(s)

Sarah Goslee, Sarah.Goslee@ars.usda.gov

Examples

# Make a random example
plotnames <- sort(rep(1:5, 3))
speciesnames <- rep(c("A", "B", "C"), 5)
freqdata <- runif(15)

data.m <- crosstab(plotnames, speciesnames, freqdata)

[Package ecodist version 1.00 Index]