10.5.2 Centred Logratio Transformation

# Fig. 10.9.: Closure problem with log-centring transformation library(StatDA) data(chorizon) x=chorizon[,c("Al2O3","CaO","Fe2O3","K2O","MgO","MnO","Na2O","P2O5","SiO2","TiO2","LOI")] xgeom=10^apply(log10(x),1,mean) x2=x/xgeom x2.obj=log10(x2) pdf("fig-10-9.pdf",width=9,height=4.5) par(mfrow=c(1,2),mar=c(4,4,2,2)) plot(x2.obj[,"SiO2"],x2.obj[,"Al2O3"],xlab="log10(SiO2/G_all)",ylab="log10(Al2O3/G_all)", pch=3,cex=0.7,cex.lab=1.2) plot(x2.obj[,"Na2O"],x2.obj[,"K2O"],xlab="log10(Na2O/G_all)",ylab="log10(K2O/G_all)", pch=3,cex=0.7,cex.lab=1.2) dev.off()