This post
explains how to build a correlogram with
the `ggally`

R package. It provides several reproducible
examples with explanation and `R`

code.

`ggpairs()`

The `ggpairs()`

function of the `GGally`

package allows to build a great scatterplot
matrix.

Scatterplots of each pair of numeric variable are drawn on the left part of the figure. Pearson correlation is displayed on the right. Variable distribution is available on the diagonal.

`ggcorr()`

The `ggcorr()`

function allows to visualize the
correlation of each pair of variable as a square. Note that the
`method`

argument allows to pick the correlation type you
desire.

It is possible to use ggplot2 aesthetics on the chart, for instance to color each category.

Change the type of plot used on each part of the correlogram. This is done with the

`upper`

and `lower`

argument.
```
# Quick display of two cabapilities of GGally, to assess the distribution and correlation of variables
library(GGally)
# From the help page:
data(tips, package = "reshape")
ggpairs(
tips[, c(1, 3, 4, 2)],
upper = list(continuous = "density", combo = "box_no_facet"),
lower = list(continuous = "points", combo = "dot_no_facet")
)
```