A
correlogram
or correlation matrix allows to analyse the relationship between each
pair of numeric variables in a dataset. It gives a quick overview of
the whole dataset. It is more used for __exploratory__ purpose than
__explanatory__.

Using the

`GGally`

package
The `GGally`

package offers great options to build
correlograms. The `ggpairs()`

function build a
classic correlogram
with scatterplot, correlation coefficient and variable distribution.
On top of that, it is possible to inject
ggplot2 code, for instance to
color categories.

Using the

`corrgram`

package
The `corrgram`

is another great alternative to build
correlograms. You can choose what to display in the upper, lower and diagonal
part of the figure: scatterplot, pie chart, text, ellipse and more.

Other methods

Lesser known ways to build correlogram with R, like the
`ellipse`

package, the `plot()`

function and the
`car`

package.