#Example vanwirdum() function  

attach(RHdata) 

#Plot all data
vanwirdum(EC = RHdata$EC, IR = RHdata$IR)  

#Plot the different groups
vanwirdum(EC = RHdata$EC, IR = RHdata$IR, group = RHdata$Period)  
#Plot the periods according to a self set color
opar <- par(mar = c(5, 5, 3, 8))
	{
	vanwirdum(EC[Period=="Summer"],IR[Period=="Summer"],pointcolor="red",add2plot=FALSE)
	vanwirdum(EC[Period=="Winter"],IR[Period=="Winter"],pointcolor="blue",add2plot=TRUE)
	vanwirdum(EC[Period=="Autumn"],IR[Period=="Autumn"],pointcolor="brown",add2plot=TRUE)
	vanwirdum(EC[Period=="Spring"],IR[Period=="Spring"],pointcolor="green",add2plot=TRUE)
	}
  
#Add legend and title
legend(x = log10(30000),y = 100, legend = c("Summer","Winter","Autumn","Spring"),col = c("red","blue","brown","green"), pch = 15, xpd = TRUE)
mtext("Data of 'Ronde Hoep',The Netherlands", side = 3, line = 1)
par(opar)