QuickR - Correlograms

I have been asked about problems with the code from the Corrgram from Quick-R

Start by reloading the original mtcars dataset. In the code from the Graphics with ggplot2 the mtcars dataset was overwritten with the factors. If the mtcars is not reloaded the previous changes cause problems with the corrgram code.

data(mtcars)

First Correlogram Example

library(corrgram)
corrgram(mtcars, order=TRUE, lower.panel=panel.shade,
  upper.panel=panel.pie, text.panel=panel.txt,
  main="Car Milage Data in PC2/PC1 Order") 

Second Correlogram Example

library(corrgram)
corrgram(mtcars, order=TRUE, lower.panel=panel.ellipse,
  upper.panel=panel.pts, text.panel=panel.txt,
  diag.panel=panel.minmax,
  main="Car Mileage Data in PC2/PC1 Order") 

Third Correlogram Example

library(corrgram)
corrgram(mtcars, order=NULL, lower.panel=panel.shade,
  upper.panel=NULL, text.panel=panel.txt,
  main="Car Milage Data (unsorted)")

Changing Colors in a Correlogram

Note that in the original code from the Quick-R website the cor.corrgram variable was not used. Adding the col to the call to the corrgram() function fixes the code and the color appears.

library(corrgram)
col.corrgram <- function(ncol){   
  colorRampPalette(c("darkgoldenrod4", "burlywood1",
  "darkkhaki", "darkgreen"))(ncol)}
corrgram(mtcars, order=TRUE, lower.panel=panel.shade,
   upper.panel=panel.pie, text.panel=panel.txt,
   col=col.corrgram,
   main="Correlogram of Car Mileage Data (PC2/PC1 Order)")