ggadd_corr: Adds a heatmap of under/over-representation of a...

In GDAtools: A Toolbox for Geometric Data Analysis and More

Adds a heatmap of under/over-representation of a supplementary variable to a cloud of individuals

Description

Adds a heatmap representing the correlation coefficients to a MCA cloud of individuals, for a numerical supplementary variable or one category of a categorical supplementary variable, using the ggplot2 framework.

Usage

ggadd_corr(p, resmca, var, cat=levels(var)[1], axes=c(1,2),
xbins=20, ybins=20, min.n=1, pal="RdYlBu", limits=NULL, legend="right")

Arguments

p	ggplot object with the cloud of variables
resmca	object of class MCA, speMCA, csMCA, stMCA or multiMCA
var	factor or numerical vector. The supplementary variable used for the heatmap.
cat	character string. numeric vector of indexes of the categories to plot (by default, ellipses are plotted for every categories). Only used if var is a factor.
axes	numeric vector of length 2, specifying the components (axes) to plot. Default is c(1,2).
xbins	integer. Number of bins in the x axis. Default is 20.
ybins	integer. Number of bins in the y axis. Default is 20.
min.n	integer. Minimal number of points for a tile to be drawn. By default, every tiles are drawn.
pal	character string. Name of a diverging ColorBrewer palette. Default is "RdYlBu".
limits	numerical vector of length 2. Lower and upper limits of the correlation coefficients for the color scale. Should be centered around 0 for a better view of under/over-representations (for example c(-0.2,0.2)). By default, the maximal absolute value of the correlation coefficients is used.
legend	the position of legends ("none", "left", "right", "bottom", "top", or two-element numeric vector). Default is right.

Details

For each tile of the heatmap, a correlation coefficient is computed between the supplementary variable and the fact of belonging to the tile. This gives a view of the under/over-representation of the supplementary variable according to the position in the cloud of individuals.

Value

a ggplot object

Author(s)

Nicolas Robette

References

Le Roux B. and Rouanet H., Multiple Correspondence Analysis, SAGE, Series: Quantitative Applications in the Social Sciences, Volume 163, CA:Thousand Oaks (2010).

Le Roux B. and Rouanet H., Geometric Data Analysis: From Correspondence Analysis to Stuctured Data Analysis, Kluwer Academic Publishers, Dordrecht (June 2004).

See Also

ggcloud_variables, ggcloud_indiv, ggadd_supvar, ggadd_interaction, ggadd_ellipses, ggadd_density

Examples

## Performs a specific MCA on 'Taste' example data set
## ignoring every 'NA' (i.e. 'not available') categories,
## draws the cloud of categories
## and adds a correlation heatmap for Age=50+.
data(Taste)
getindexcat(Taste[,1:11])
mca <- speMCA(Taste[,1:11],excl=c(3,6,9,12,15,18,21,24,27,30,33))
p <- ggcloud_indiv(mca, col='lightgrey')
ggadd_corr(p, mca, var=Taste$Age, cat="50+", xbins=10, ybins=10)

GDAtools documentation built on March 18, 2022, 5:13 p.m.