ggmatrix(): Plot matrix

Barret Schloerke

Oct 29, 2015

library(GGally)
#> Loading required package: ggplot2
#> Registered S3 method overwritten by 'GGally':
#>   method from   
#>   +.gg   ggplot2

GGally::ggmatrix()

ggmatrix() is a function for managing multiple plots in a matrix-like layout. It was designed to adapt to any number of columns and rows. This allows for very customized plot matrices.

Generic Example

The examples below use plots labeled 1 to 6 to distinguish where the plots are being placed.

plotList <- list()
for (i in 1:6) {
  plotList[[i]] <- ggally_text(paste("Plot #", i, sep = ""))
}

# bare minimum of plotList, nrow, and ncol
pm <- ggmatrix(plotList, 2, 3)
pm

# provide more information
pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 3,
  xAxisLabels = c("A", "B", "C"),
  yAxisLabels = c("D", "E"),
  title = "Matrix Title"
)
pm

# display plots in column order
pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 3,
  xAxisLabels = c("A", "B", "C"),
  yAxisLabels = c("D", "E"),
  title = "Matrix Title",
  byrow = FALSE
)
pm

Matrix Subsetting

Individual plots may be retrieved from the plot matrix and can be placed in the plot matrix.

pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 3,
  xAxisLabels = c("A", "B", "C"),
  yAxisLabels = c("D", "E"),
  title = "Matrix Title"
)
pm

p2 <- pm[1, 2]
p3 <- pm[1, 3]
p2

p3

pm[1, 2] <- p3
pm[1, 3] <- p2
pm

Themes

library(ggplot2)
pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 3,
  xAxisLabels = c("A", "B", "C"),
  yAxisLabels = c("D", "E"),
  title = "Matrix Title",
  byrow = FALSE
)
pm <- pm + theme_bw()
pm

Axis Control

The X and Y axis have booleans to turn on/off the individual plot’s axes on the bottom and left sides of the plot matrix. To save time, showAxisPlotLabels can be set to override showXAxisPlotLabels and showYAxisPlotLabels.

pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 3,
  xAxisLabels = c("A", "B", "C"),
  yAxisLabels = c("D", "E"),
  title = "No Left Plot Axis",
  showYAxisPlotLabels = FALSE
)
pm

pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 3,
  xAxisLabels = c("A", "B", "C"),
  yAxisLabels = c("D", "E"),
  title = "No Bottom Plot Axis",
  showXAxisPlotLabels = FALSE
)
pm

pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 3,
  xAxisLabels = c("A", "B", "C"),
  yAxisLabels = c("D", "E"),
  title = "No Plot Axes",
  showAxisPlotLabels = FALSE
)
pm

Strips Control

By default, the plots in the top row and the right most column will display top-side and right-side strips respectively (showStrips = NULL). If all strips need to appear in each plot, showStrips may be set to TRUE. If all strips should not be displayed, showStrips may be set to FALSE.

data(tips)
subPlot <- function(smoker_value, sex_value) {
  ggplot(
    data = tips[tips$smoker == smoker_value & tips$sex == sex_value, ],
    aes(x = !!as.name("total_bill"), y = !!as.name("tip"))
  ) +
    geom_point() +
    facet_grid(time ~ day)
}
plotList <- list(
  subPlot("No", "Female"),
  subPlot("Yes", "Female"),
  subPlot("No", "Male"),
  subPlot("Yes", "Male")
)

pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 2,
  yAxisLabels = c("Female", "Male"),
  xAxisLabels = c("Non Smoker", "Smoker"),
  title = "Total Bill vs Tip",
  showStrips = NULL # default
)
pm

pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 2,
  yAxisLabels = c("Female", "Male"),
  xAxisLabels = c("Non Smoker", "Smoker"),
  title = "Total Bill vs Tip",
  showStrips = TRUE
)
pm

pm <- ggmatrix(
  plotList,
  nrow = 2, ncol = 2,
  yAxisLabels = c("Female", "Male"),
  xAxisLabels = c("Non Smoker", "Smoker"),
  title = "Total Bill vs Tip",
  showStrips = FALSE
)
pm