cov2per {goeveg}

Conversion between cover-abundance codes and percentage cover

Description

These functions perform a conversion between cover-abundance codes from different survey scales and percentage cover. They can be applied on a matrix-like object or a single vector.

cov2per performs conversion from cover-abundance to percentage values

per2cov performs conversion from percentage to cover-abundance values

You may chose between a set of scales with pre-defined conversion values, in scale_tabs or define your own conversion table following the same format.

Usage

cov2per(matrix, scale = "braun.blanquet", multiscale = FALSE)

per2cov(matrix, scale = "braun.blanquet", multiscale = FALSE)

Arguments

matrix

Community data, a vector or matrix-like object with cover-abundance values

scale

Cover-abundance scale (from scale_tabs) or dataframe with custom conversion table following the same format.

multiscale

A logical evaluation to FALSE (default) or TRUE indicating whether individual scales per sample should be used. For individual scales, you must provide a vector of the same length as the number of samples to the scale argument, defining the scale (from scale_tabs) for each sample (with samples as rows in matrix).

Value

A dataframe or vector containing the transformed data

Details

If scales are not only cover-based but also abundance-based (e.g. Braun-Blanquet, Kohler) there are often no unique definitions about their conversion into percentage cover. Therefore it is necessary to define and give reference to the applied conversion table.

Cover-abundance codes are transformed into the mean percentage cover of their class. For the conversion of percentage cover to cover-abundance codes, all values between the lower and upper border of the class are transformed into the corresponding code.

The included cover-abundance scales and the associated conversion tables with references are explained in scale_tabs. On this site you also find definitions for defining a custom table.

Author(s)

Friedemann von Lampe ([e-mail])

See Also

scale_tabs for explanation and references of included conversion tables

Examples

## Conversion of species matrix with percentage cover to Braun-Blanquet values
schedenveg.bb <- per2cov(schedenveg)

## Conversion of only 10 samples to Londo values
schedenveg.londo <- per2cov(schedenveg[, 1:10], scale = "londo")

## Conversion of species matrix with Braun-Blanquet values to percentage cover
schedenveg.per <- cov2per(schedenveg.bb)