Visual Correlation Matrix

Visualization of a correlation matrix. On top the (absolute) value of the correlation plus the result of the cor.test as stars. On bottom, the bivariate scatterplots, with a fitted line. On the diagonal, an histogram of each variable.

Usage

hydropairs(x, dec = 3, use = "pairwise.complete.obs", method = "pearson",...)

Arguments

x: data.frame or matrix object with measurements at several locations. Each column of x represent values measured at different locations.
dec: decimal places to be used for showing the correlation values
use: See cor. An optional character string giving a method for computing covariances in the presence of missing values. This must be (an abbreviation of) one of the strings "everything", "all.obs", "complete.obs", "na.or.complete", or "pairwise.complete.obs".
method: See cor. A character string indicating which correlation coefficient (or covariance) is to be computed. One of "pearson" (default), "kendall", or "spearman", can be abbreviated
...: further arguments passed to or from other methods, in particular it is used in the pairs function.

Value

On top: the (absolute) value of the correlation plus the result of the cor.test as points
On bottom: the bivariate scatterplots, with a fitted line
On diagonal: histograms (from pairs)

Author

Mauricio Zambrano-Bigiarini, mzb.devel@gmail

Note

Original idea taken from the R Graph Gallery (nowadays not available on its original link: http://addictedtor.free.fr/graphiques/graphcode.php?graph=137).

Histogram panel was taken from the R help of the original pairs function

Examples

## Loading the monthly time series of precipitation within the Ebro River basin.
data(EbroPPtsMonthly)

## Visualizing the correlation among the monthly precipitation values 
## of the first 3 gauging stations in 'EbroPPtsMonthly'. 
## The first column of 'EbroPPtsMonthly' has the dates.
hydropairs(EbroPPtsMonthly[,2:4])