While legends are the most commonly used method of providing a key to read multiple-variable graphs, they are often not the easiest to read. Labeling lines directly is one way of getting around this problem.
We will use the base graphics library for this recipe, so all you need to do is run the recipe at the R prompt. It is good practice to save your code as a script for use again later.
Let's use the gdp.txt
example dataset to look at the trends in annual GDP of five countries:
gdp<-read.table("gdp_long.txt",header=T) library(RColorBrewer) pal<-brewer.pal(5,"Set1") par(mar=par()$mar+c(0,0,0,2),bty="l") plot(Canada~Year,data=gdp,type="l",lwd=2,lty=1,ylim=c(30,60), col=pal[1],main="Percentage change in GDP",ylab="") mtext(side=4,at=gdp$Canada[length(gdp$Canada)],text="Canada", col=pal[1],line=0.3,las=2) lines(gdp$France~gdp$Year,col=pal[2],lwd=2) mtext(side=4,at=gdp$France[length(gdp$France...