Multiple plots in one page

In this post I will show you how to arrange multiple plots in single one page with:

Classic R command

Ploting multiple graphs in single one page (or canvas) with classic R command is straightforward and easy.

The key lies in par.

par(mfrow = c(3, 2))  # 3 rows and 2 columns
for (i in c("Sturges", "st", "Scott", "sc", "FD", "fr")) {
    hist(cars$speed, breaks = i, main = paste("method is", i, split = ""))
}

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ggplot2

gridExtra

We all know ggplot2 is elegant. And It cannot easily plotted in sigle one page just with defined par. That is why we need gridExtra. Just like the official wiki introduces, grid_arrage will make it work.

library(ggplot2)
library(grid)
library(gridExtra)
p1 = qplot(1:10, rnorm(10))
p2 = qplot(1:10, rnorm(10))
grid.arrange(p1, p2, ncol = 2, main = "Main title")

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gridExtra-like custom funcions

From the Cookbook for R/), multiplot function is costumer designed function. You can copy the codes, and it can work like gridExtra.

# muliplot(p1,p2,p3,...,cols=5)

par-like custom functions

List all plots

But here is a disadvantage. What if all the plots have tiny differences between each of them? The classic R command for loop can make it. It is a huge waste of time to establish every plot named in p1, p2, p3, etc, let alone input them one by one.

Still use multiplot. But here we use list function. Inside the multiplot function, there is a flag, named: plotlist.

plots <- list()  # new empty list
for (i in 1:6) {
    p1 = qplot(1:10, rnorm(10), main = i)
    plots[[i]] <- p1  # add each plot into plot list
}
multiplot(plotlist = plots, cols = 3)

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Sensational!!!

Layouts

What if you wish to define territorries for each plot? You should define Layout flag.

library(ggplot2)
for (i in 1:5) {
    p1 = qplot(1:10, rnorm(10), main = i)
    plots[[i]] <- p1
}
layout <- matrix(c(1, 1, 2, 3, 4, 5), nrow = 2, byrow = TRUE)
multiplot(plotlist = plots, layout = layout)

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FALSE Error: Invalid 'layout.pos.row' in viewport

How does it work?

The key is to define the area. The following code will show you how:

a <- qplot(1:10, rnorm(10), main = "a")
b <- qplot(1:10, rnorm(10), main = "b")
c <- qplot(1:10, rnorm(10), main = "c")
grid.newpage()
pushViewport(viewport(layout = grid.layout(2, 2)))
vplayout <- function(x, y) viewport(layout.pos.row = x, layout.pos.col = y)
print(a, vp = vplayout(1, 1:2))  # key is to define vplayout
print(b, vp = vplayout(2, 1))
print(c, vp = vplayout(2, 2))

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