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.
cov2per(matrix, scale = "braun.blanquet", multiscale = FALSE)
per2cov(matrix, scale = "braun.blanquet", multiscale = FALSE)Community data, a vector or matrix-like object with cover-abundance values
Cover-abundance scale (from scale_tabs) or dataframe with custom conversion table following the same format.
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).
A dataframe or vector containing the transformed data
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.
scale_tabs for explanation and references of included conversion tables
## 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)