7.3.1 Using Geochemical Maps to Identify a Reasonable Threshold

# Fig 7.2: Map for Cu in O-Horizon library(StatDA) data(ohorizon) data(kola.background) X=ohorizon[,"XCOO"] Y=ohorizon[,"YCOO"] # true representation of x and y axis of map for plot xwid=diff(range(X))/12e4 ywid=diff(range(Y))/12e4 pdf("fig-7-2.pdf",width=2*xwid,height=1*ywid) par(mfrow=c(1,2),mar=c(1.5,1.5,1.5,1.5)) ### NEW MAP: EDA 5 el=(ohorizon[,"Cu"]) # generate plot with background plot(X,Y,frame.plot=FALSE,xaxt="n",yaxt="n",xlab="",ylab="",type="n") plotbg(map.col=c("gray","gray","gray","gray"),add.plot=T) SymbLegend(X,Y,el,type="percentile",qutiles<-c(0,0.05,0.25,0.75,0.95,1),symbtype="EDA",symbmagn=0.8, leg.position="topright",leg.title="Cu [mg/kg]",leg.title.cex=0.7,leg.round=2,leg.wid=4,leg.just="right") # Text text(min(X)+diff(range(X))*4/7,max(Y),paste(qutiles*100,collapse=","),cex=0.7) text(min(X)+diff(range(X))*4/7,max(Y)-diff(range(Y))/25,"Percentiles",cex=0.75) # scalebar scalebar(761309,7373050,861309,7363050,shifttext=-0.5,shiftkm=37e3,sizetext=0.8) # North arrow Northarrow(362602,7818750,362602,7878750,362602,7838750,Alength=0.15,Aangle=15,Alwd=1.3,Tcex=1.6) ### NEW MAP: el=(ohorizon[,"Cu"]) # take symbols according to quantiles: q=13 # symbols and size symb=c(1,3) ssize=c(0.4,0.9) # generate plot with packground plot(X,Y,frame.plot=FALSE,xaxt="n",yaxt="n",xlab="",ylab="",type="n") plotbg(map.col=c("gray","gray","gray","gray"),add.plot=T) # plot symbols: points(X[el<=q], Y[el<=q], pch=symb[1], cex=ssize[1]) points(X[el>q], Y[el>q], pch=symb[2], cex=ssize[2]) # Legend legend("topright",pch=rev(symb),pt.cex=rev(ssize), legend=c("> 13","<= 13"), title="Cu [mg/kg]", cex=0.75) # scalebar scalebar(761309,7373050,861309,7363050,shifttext=-0.5,shiftkm=37e3,sizetext=0.8) # North arrow Northarrow(362602,7818750,362602,7878750,362602,7838750,Alength=0.15,Aangle=15,Alwd=1.3,Tcex=1.6) dev.off()