steppe {ade4}R Documentation

Transect in the Vegetation

Description

This data set gives the presence-absence of 37 species on 515 sites.

Usage

data(steppe)

Format

steppe is a list of 2 components.

tab
is a data frame with 512 rows (sites) and 37 variables (species) in presence-absence.
esp.names
is a vector of the species names.

Source

Estève, J. (1978) Les méthodes d'ordination : éléments pour une discussion. in J. M. Legay and R. Tomassone, editors. Biométrie et Ecologie, Société Française de Biométrie, Paris, 223–250.

Examples

par(mfrow = c(3,1))
data(steppe)
w1 <- col(as.matrix(steppe$tab[,1:15]))
w1 <- as.numeric(w1[steppe$tab[,1:15] > 0])
w2 <- row(as.matrix(steppe$tab[,1:15]))
w2 <- as.numeric(w2[steppe$tab[,1:15] > 0])
plot(w2, w1, pch = 20)
plot(dudi.pca(steppe$tab, scan = FALSE, scale = FALSE)$li[,1],
    pch = 20, ylab = "PCA", xlab = "", type = "b")
plot(dudi.coa(steppe$tab, scan = FALSE)$li[,1], pch = 20, 
    ylab = "COA", xlab = "", type = "b")
par(mfrow = c(1,1))

Worked out examples


> library(ade4)
> ### Name: steppe
> ### Title: Transect in the Vegetation
> ### Aliases: steppe
> ### Keywords: datasets
> 
> ### ** Examples
> 
> par(mfrow = c(3,1))
> data(steppe)
> w1 <- col(as.matrix(steppe$tab[,1:15]))
> w1 <- as.numeric(w1[steppe$tab[,1:15] > 0])
> w2 <- row(as.matrix(steppe$tab[,1:15]))
> w2 <- as.numeric(w2[steppe$tab[,1:15] > 0])
> plot(w2, w1, pch = 20)
> plot(dudi.pca(steppe$tab, scan = FALSE, scale = FALSE)$li[,1],
+     pch = 20, ylab = "PCA", xlab = "", type = "b")
> plot(dudi.coa(steppe$tab, scan = FALSE)$li[,1], pch = 20, 
+     ylab = "COA", xlab = "", type = "b")
> par(mfrow = c(1,1))
> 
> 
> 
> 

[Package ade4 Index]