Arranging Ggally Plots with Gridextra

Arranging GGally plots with gridExtra?

Unfortunately, I cannot see how that is possible.

First, it's not going to work with gridExtra, since arrangeGrob operates on TableGrob objects:

> ggplotGrob(qplot(1:100))
stat_bin: binwidth defaulted to range/30. Use 'binwidth = x' to adjust this.
TableGrob (6 x 5) "layout": 8 grobs
  z     cells       name                                 grob
1 0 (1-6,1-5) background      rect[plot.background.rect.3349]
2 3 (3-3,3-3)     axis-l absoluteGrob[GRID.absoluteGrob.3341]
3 1 (4-4,3-3)     spacer                       zeroGrob[NULL]
4 2 (3-3,4-4)      panel               gTree[GRID.gTree.3329]
5 4 (4-4,4-4)     axis-b absoluteGrob[GRID.absoluteGrob.3335]
6 5 (5-5,4-4)       xlab         text[axis.title.x.text.3343]
7 6 (3-3,2-2)       ylab         text[axis.title.y.text.3345]
8 7 (2-2,4-4)      title           text[plot.title.text.3347]

The inner representation of ggpairs object only contains methods to be called, not actual grobs:

> str(p1$plots)
List of 9
 $ : chr "ggally_diagAxis(ggally_data, ggplot2::aes(x = var1))"
 $ : chr "ggally_cor(ggally_data, ggplot2::aes(x = var2, y = var1))"
 $ : chr "ggally_cor(ggally_data, ggplot2::aes(x = var3, y = var1))"
 $ : chr "ggally_points(ggally_data, ggplot2::aes(x = var1, y = var2))"
 $ : chr "ggally_diagAxis(ggally_data, ggplot2::aes(x = var2))"
 $ : chr "ggally_cor(ggally_data, ggplot2::aes(x = var3, y = var2))"
 $ : chr "ggally_points(ggally_data, ggplot2::aes(x = var1, y = var3))"
 $ : chr "ggally_points(ggally_data, ggplot2::aes(x = var2, y = var3))"
 $ : chr "ggally_diagAxis(ggally_data, ggplot2::aes(x = var3))"

The whole work of constructing actual grobs is done by GGally:::print.ggpairs. Take a look at the source code and you will see grid.newpage() along with multiple popViewports and pushViewports. This means that even low-level grid approach (e.g. described here) is not applicable, since your grid constructions will get overwritten by GGally:::print.ggpairs.

There's always a way, of course. Modifying the source code is always an option, though I believe it's a long and difficult path for your task. I'd be happy to be proven wrong if anyone can come up with a simple workaround.

R: arranging multiple plots together using gridExtra

If you want to keep the approach you are using just add

par(mfrow=c(2,2))

before all four plots.

If you want everything on the same line add instead

par(mfrow=c(1,4))

Arrange many plots using gridExtra

I had to change the qplot loop call slightly (i.e. put the factors in the data frame) as it was throwing a mismatched size error. I'm not including that bit since that part is obviously working in your environment or it was an errant paste.

Try adjusting your widths units like this:

widths=unit(c(1000,50),"pt")

And you'll get something a bit closer to what you were probably expecting:

And, I can paste code now a few months later :-)

library(ggplot2)
library(gridExtra)

df <- data.frame(price=matrix(sample(1:1000, 100, replace = TRUE), ncol = 1))

df$size1 = 1:nrow(df)
df$size1 = cut(df$size1, breaks=11)
df=df[sample(nrow(df)),]
df$size2 = 1:nrow(df)
df$size2 = cut(df$size2, breaks=11)
df=df[sample(nrow(df)),]
df$clarity = 1:nrow(df)
df$clarity = cut(df$clarity, breaks=6)

# Create one graph for each size1, plotting the median price vs. the size2 by clarity:
for (c in 1:length(table(df$size1))) {

  mydf = df[df$size1==names(table(df$size1))[c],]
  mydf = aggregate(mydf$price, by=list(mydf$size2, mydf$clarity),median);   
  names(mydf)[1] = 'size2'
  names(mydf)[2] = 'clarity'
  names(mydf)[3] = 'median_price'
  mydf$clarity <- factor(mydf$clarity)

  assign(paste("p", c, sep=""), 
         qplot(data=mydf, 
               x=as.numeric(size2), 
               y=median_price, 
               group=clarity, 
               geom="line", colour=clarity, 
               xlab = "number of samples", 
               ylab = "median price", 
               main = paste("region number is ",c, sep=''), 
               plot.title=element_text(size=10)) + 
           scale_colour_discrete(name = "clarity") + 
           theme_bw() + theme(axis.title.x=element_text(size = rel(0.8)), 
                              axis.title.y=element_text(size = rel(0.8)), 
                              axis.text.x=element_text(size=8),
                              axis.text.y=element_text(size=8) ))
}

# Use gridExtra to arrange the 11 plots:

g_legend<-function(a.gplot){
  tmp <- ggplot_gtable(ggplot_build(a.gplot))
  leg <- which(sapply(tmp$grobs, function(x) x$name) == "guide-box")
  legend <- tmp$grobs[[leg]]
  return(legend)}

mylegend<-g_legend(p1)

grid.arrange(arrangeGrob(p1 + theme(legend.position="none"),
                         p2 + theme(legend.position="none"),
                         p3 + theme(legend.position="none"),
                         p4 + theme(legend.position="none"),
                         p5 + theme(legend.position="none"),
                         p6 + theme(legend.position="none"),
                         p7 + theme(legend.position="none"),
                         p8 + theme(legend.position="none"),
                         p9 + theme(legend.position="none"),
                         p10 + theme(legend.position="none"),
                         p11 + theme(legend.position="none"),
                         top ="Main title",
                         left = ""), mylegend, 
             widths=unit(c(1000,50),"pt"), nrow=1)

Edit (16/07/2015): with gridExtra >= 2.0.0, the main parameter has been renamed top.

Using grid.arrange with multiple plots

The only thing missing is that when you are inputting multiple plots, they need to be in a list structure.

If you change your last line of code

from:

p = do.call("grid.arrange", c(plot_1[[1]], plot_1[[2]], plot_2, ncol=1))

to:

p = do.call("grid.arrange", c(list(plot_1[[1]], plot_1[[2]], plot_2), ncol=1))

I believe that will solve the issue.

plots generated by 'ggpair' and 'ggplot' side-by-side

For a quick way you can create a grid object from the ggpairs plot. It is perhaps a bit less robust than Roland's method of writing a new ggpairs print method as from the ?grid.grab help page. * ... is not guaranteed to faithfully replicate all possible grid output." (although using wrap argument indicates it should, but its beyond my ken)

library(ggplot2)
library(grid)
library(gridExtra)
library(GGally)

df <- data.frame(y = rnorm(100))    
p1 <- ggpairs(iris, colours='Species')
p2 <- ggplot(df, aes(x=1:100, y=y)) + geom_line()

g <- grid.grabExpr(print(p1))
grid.arrange(g, p2, widths=c(0.8,0.2))

Store output from gridExtra::grid.arrange into an object

The code in your edit does not work properly since you didn't load gridExtra.

library(gridExtra)
y <- arrangeGrob(p1, p2, ncol = 1)
class(y)
#[1] "gtable" "grob"   "gDesc"
grid.draw(y)

Edit: since version 2.0.0, my comment about grid dependency below is no longer valid, since grid is now imported.

Edit: With gridExtra version >= 2.0.0, there is no need to attach either package,

p <- ggplot2::qplot(1,1)
x <- gridExtra::arrangeGrob(p, p)
grid::grid.draw(x)

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