taylor.diagram: Taylor diagram

In plotrix: Various Plotting Functions

Taylor diagram

Description

Display a Taylor diagram

Usage

 taylor.diagram(ref,model,add=FALSE,col="red",pch=19,pos.cor=TRUE,
  xlab="Standard deviation",ylab="",main="Taylor Diagram",
  show.gamma=TRUE,ngamma=3,gamma.col=8,sd.arcs=0,
  ref.sd=FALSE,sd.method="sample",grad.corr.lines=c(0.2,0.4,0.6,0.8,0.9),
  pcex=1,cex.axis=1,normalize=FALSE,mar=c(4,3,4,3),...)

Arguments

ref	numeric vector - the reference values.
model	numeric vector - the predicted model values.
add	whether to draw the diagram or just add a point.
col	the color for the points displayed.
pch	the type of point to display.
pos.cor	whether to display only positive (‘⁠TRUE⁠’) or all values of correlation (‘⁠FALSE⁠’).
xlab,ylab	plot axis labels.
main	title for the plot.
show.gamma	whether to display standard deviation arcs around the reference point (only for ‘⁠pos.cor=TRUE⁠’).
ngamma	the number of gammas to display (default=3).
gamma.col	color to use for the gamma arcs (only with pos.cor=TRUE).
sd.arcs	whether to display arcs along the standard deviation axes (see Details).
ref.sd	whether to display the arc representing the reference standard deviation.
sd.method	Whether to use the sample or estimated population SD.
grad.corr.lines	the values for the radial lines for correlation values (see Details).
pcex	character expansion for the plotted points.
cex.axis	character expansion for the axis text.
normalize	whether to normalize the models so that the reference has a standard deviation of 1.
mar	margins - only applies to the ‘⁠pos.cor=TRUE⁠’ plot.
...	Additional arguments passed to ‘⁠plot⁠’.

Details

The Taylor diagram is used to display the quality of model predictions against the reference values, typically direct observations.

A diagram is built by plotting one model against the reference, then adding alternative model points. If ‘⁠normalize=TRUE⁠’ when plotting the first model, remember to set it to ‘⁠TRUE⁠’ when plotting additional models.

Two displays are available. One displays the entire range of correlations from -1 to 1. Setting ‘⁠pos.cor⁠’ to ‘⁠FALSE⁠’ will produce this display. The -1 to 1 display includes a radial grid for the correlation values. When ‘⁠pos.cor⁠’ is set to ‘⁠TRUE⁠’, only the range from 0 to 1 will be displayed. The ‘⁠gamma⁠’ lines and the arc at the reference standard deviation are optional in this display.

Both the standard deviation arcs and the gamma lines are optional in the ‘⁠pos.cor=TRUE⁠’ version. Setting ‘⁠sd.arcs⁠’ or ‘⁠grad.corr.lines⁠’ to zero or FALSE will cause them not to be displayed. If more than one value is passed for ‘⁠sd.arcs⁠’, the function will try to use the values passed, otherwise it will call ‘⁠pretty⁠’ to calculate the values.

Value

The values of ‘⁠par⁠’ that preceded the function. This allows the user to add points to the diagram, then restore the original values. This is only necessary when using the 0 to 1 correlation range.

Author(s)

Olivier Eterradossi with modifications by Jim Lemon

References

Taylor, K.E. (2001) Summarizing multiple aspects of model performance in a single diagram. Journal of Geophysical Research, 106: 7183-7192.

Examples

 # fake some reference data
 ref<-rnorm(30,sd=2)
 # add a little noise
 model1<-ref+rnorm(30)/2
 # add more noise
 model2<-ref+rnorm(30)
 # display the diagram with the better model
 oldpar<-taylor.diagram(ref,model1)
 # now add the worse model
 taylor.diagram(ref,model2,add=TRUE,col="blue")
 # get approximate legend position
 lpos<-1.5*sd(ref)
 # add a legend
 legend(lpos,lpos,legend=c("Better","Worse"),pch=19,col=c("red","blue"))
 # now restore par values
 par(oldpar)
 # show the "all correlation" display
 taylor.diagram(ref,model1,pos.cor=FALSE)
 taylor.diagram(ref,model2,add=TRUE,col="blue")

plotrix documentation built on Nov. 10, 2023, 5:07 p.m.