TT.chemometrics.alr {soiltexture}

Compute the additive log-ratio transformation of compositional data.

Description

Function that compute the additive log-ratio transformation of compositional data (here texture data). This a a copy-paste-and-rename of the alr function provided by the package chemometrics: P. Filzmoser and K. Varmuza (2008). chemometrics: Multivariate Statistical Analysis in Chemometrics. R package version 0.4. The function has been modified so it returns NA when a value is below or equal to zero (this happens when using a regular grid of texture data, for practical reasons). The function has also been modified so it uses column name rather than column index.

Usage

TT.chemometrics.alr(X, divisorvar, css.names)

Arguments

X

A data.frame containing soil texture data

divisorvar

number of ratioing variable

css.names

See TT.plot

Author(s)

Julien Moeys [aut, cre], Wei Shangguan [ctb], Rainer Petzold [ctb], Budiman Minasny [ctb], Bogdan Rosca [ctb], Nic Jelinski [ctb], Wiktor Zelazny [ctb], Rodolfo Marcondes Silva Souza [ctb], Jose Lucas Safanelli [ctb], Alexandre ten Caten [ctb]