How to remove white spcaes around a bottom-aligned legend with cowplot - r

I am using cowplot to arrange two plots with a common legend below. The approach works, yet the legend has whitespace around I would like to get rid of.
Note: I am ware of the ggpubr::ggarange common.legend option I though want to stick to cowplot::plot_grid (which masks ggpubr::get_legend)
library(tidyverse)
library(ggpubr)
library(cowplot)
theme_set(theme_cowplot())
p1 <- iris %>%
ggplot(aes(x=Sepal.Width,y=Petal.Width,color=Species)) +
geom_point() + coord_fixed()
p2 <- iris %>%
ggplot(aes(x=Sepal.Width,y=Petal.Width,color=Species)) +
geom_point() + coord_fixed()
compound_plot <- plot_grid(p1 + theme(legend.position="none"),
p2 + theme(legend.position="none"),
ncol = 2,
labels = c("A","B"))
legend <- get_legend(p1 +
theme(legend.direction = "horizontal",
legend.justification="center" ,
legend.box.just = "bottom"))
plot_grid(compound_plot,
legend,
ncol = 1)
Thanks in advance!

You can set rel_heights inside plot_grid
plot_grid(compound_plot,
legend,
ncol = 1, rel_heights = c(0.95, 0.05))

Related

strip.position external in two columns facet_wrap plot

in two columns facet_wrap figures, it would be handy and nicer to have the name of the facet and the axis on the left for the left column, and on the right for the right column, in order to have a compact plot, with the facets close together.
ggplot(economics_long, aes(date, value)) +
geom_line() +
labs(y="") +
facet_wrap(~variable, scales = "free_y", ncol = 2, strip.position = "left") +
theme(strip.background = element_blank(), strip.placement = "outside")
As far as I know, there is no way to do this in vanilla ggplot2. If you're comfortable with gtables, you might find the following doable.
library(ggplot2)
# Base plot
p <- ggplot(economics_long, aes(date, value)) +
geom_line() +
labs(y="") +
theme(strip.background = element_blank(), strip.placement = "outside")
# Left aligned strips/axes
left <- p +
facet_wrap(~variable, scales = "free_y", ncol = 2, strip.position = "left")
# Right aligned strips/axes
right <- p +
facet_wrap(~variable, scales = "free_y", ncol = 2, strip.position = "right") +
scale_y_continuous(position = "right")
# Convert to gtables
left <- ggplotGrob(left)
right <- ggplotGrob(right)
# Combine parts of left and right
# Column numbers found by browsing through layout
gt <- cbind(left[, 1:7], right[, 9:ncol(right)])
# Render
grid::grid.newpage(); grid::grid.draw(gt)
Created on 2021-10-20 by the reprex package (v2.0.1)
To find the panel positions in a more programmatically than judging the table layout manually, my best guess is to do this:
panels_left <- panel_cols(left)$l
panels_right <- panel_cols(right)$l
# The -2 is to include the left axis space (zero width because of absence)
# and the panel spacing
gt <- cbind(left[, 1:panels_left[1]],
right[, (panels_right[2]-2):ncol(right)])
grid::grid.newpage(); grid::grid.draw(gt)

Align a shared legend in cowplot

I'm looking to use the cowplot package to give two ggplots a shared legend. However, how can I center the shared legend when there's an even number of plots.
Here's some example code:
library(ggplot2)
library(cowplot)
library(rlang)
# down-sampled diamonds data set
dsamp <- diamonds[sample(nrow(diamonds), 1000), ]
# function to create plots
plot_diamonds <- function(xaes) {
xaes <- enquo(xaes)
ggplot(dsamp, aes(!!xaes, price, color = clarity)) +
geom_point() +
theme_half_open(12) +
# we set the left and right margins to 0 to remove
# unnecessary spacing in the final plot arrangement.
theme(plot.margin = margin(6, 0, 6, 0))
}
# make two plots
p1 <- plot_diamonds(carat)
p2 <- plot_diamonds(depth) + ylab(NULL)
# arrange the three plots in a single row
prow <- plot_grid(
p1 + theme(legend.position="none"),
p2 + theme(legend.position="none"),
align = 'vh',
labels = c("A", "B"),
hjust = -1,
nrow = 1
)
prow
# extract a legend that is laid out horizontally
legend_b <- get_legend(
p1 +
guides(color = guide_legend(nrow = 1)) +
theme(legend.position = "bottom")
)
# add the legend underneath the row we made earlier. Give it 10%
# of the height of one plot (via rel_heights).
plot_grid(prow, legend_b, ncol = 1, rel_heights = c(1, .1))
Which produces this image:
As you can see, cow_plot puts the the legend is located underneath the left image. Is there a way to make this shared legend centered between the two images?
Change the theme like below;
legend_b <- get_legend( p1 +
guides(color = guide_legend(nrow = 1)) +
theme(legend.direction = "horizontal",
legend.justification="center",
legend.box.just = "bottom")
)

Decrease margins between plots when using cowplot

I would like to combine some graphs together using cowplot. But I cannot change the margin sizes. I want to use only one y-axes, but than the margin is still quite large, which I want to decrease. I have used the plot.margin code from ggplot, although that works when I look at the single plot, it doesn't seem to work when the plots are combined.
I have made some example code:
library(ggplot2)
library(cowplot)
x <- c("a", "b")
y1 <- c(3,6)
y2 <- c(10,15)
data1 <- data.frame(x,y1)
data2 <- data.frame(x, y2)
ylab1 <- ylab("Very nice y values")
xlab1 <- xlab("Very nice factors")
plot1 <- ggplot(data1, aes(x=x, y = y1)) +
geom_bar(stat ="identity", position=position_dodge(), fill = "grey")+
theme(plot.margin = unit(c(0.5,0.5,0.5,0.5), "cm")) + xlab1 + ylab1
plot1
ylab2 <- ylab("")
xlab2 <- xlab("Very nice factors")
plot2 <- ggplot(data2, aes(x=x, y = y2)) +
geom_bar(stat = "identity",position=position_dodge(), fill = "grey")+
theme(plot.margin = unit(c(0.5,0.5,0.5,-0.5), "cm")) + xlab2 + ylab2
plot2
plot3 <- plot_grid(plot1, plot2, labels = c("A", "B"), align = "hv",nrow = 1, ncol = 2)
plot3 # Quite large margin between the two plots
I am aware that I could avoid this problem by using facets, however my real plot is rather more complicated than this graph.
Increasing the space between plots in plot_grid was also addressed in this issue.
An extra interesting solution is the one suggested in this comment - try to add an extra empty plot between the two plots and adjust the relative columns widths:
plot4 <- plot_grid(plot1, NULL, plot2, rel_widths = c(1, 0, 1), align = "hv",
labels = c("A", "B"), nrow = 1)
plot4
Can even try negative values in rel_widths, which gives better results:
plot5 <- plot_grid(plot1, NULL, plot2, rel_widths = c(1, -0.1, 1), align = "hv",
labels = c("A", "B"), nrow = 1)
plot5
So, try a combination of adjusting the plot.margin (as answered by #J.Con) and adding an extra empty plot with tweaking rel_widths.
EDIT 2019-12-11
Also check out this comment of the author of cowplot (Claus Wilke):
For those kinds of problems I would now recommend the patchwork library. It's inherently difficult with plot_grid(), due to its underlying design
So, a fast example with patchwork based on their vignette Adding Annotation and Style goes like this:
library(patchwork)
plot3 <- plot1 + plot2 +
plot_annotation(tag_levels = 'A') &
theme(plot.tag = element_text(size = 8))
plot3
Created on 2019-12-11 by the reprex package (v0.3.0)
Your plot.margins were actually working against you. Set them to zero to fill up that white space.
plot1 <- ggplot(data1, aes(x=x, y = y1)) +
geom_bar(stat ="identity", position=position_dodge(), fill = "grey")+
theme(plot.margin = unit(c(0,0,0,0), "cm")) + xlab1 + ylab1
plot1
ylab2 <- ylab("")
xlab2 <- xlab("Very nice factors")
plot2 <- ggplot(data2, aes(x=x, y = y2)) +
geom_bar(stat = "identity",position=position_dodge(), fill = "grey")+
theme(plot.margin = unit(c(0,0,0,0), "cm")) + xlab2 + ylab2
plot2
plot3 <- plot_grid(plot1, plot2, labels = c("A", "B"), align = "hv",nrow = 1, ncol = 2)
plot3

Specify plot height in plot_grid with 'hv' aligment: cowplot

I have been using the plot_grid command from cowplot to arrange my plots. I use the labeling feature, and my plots all look the same in that regard. However, when I 'hv' align some plots that have very different y-axis limits, such as the one below, it appears the height of the plot with shortest range of y is used.
If I just 'v' align the plot it looks better in some respects, but it is hard to resize the plot and have the labels looking good. I'd prefer the plot height not consider the x-axis labels, etc, like above.
Using gtables, I can get the desired width/height (below), but these leaves me without the consistent labels across all the figures in a document. Can I use the 'hv' alignment with cowplot and specify which plot height to use?
library(ggplot2)
library(dplyr)
library(scales)
library(grid)
library(cowplot)
data(iris)
iris <- iris %>% mutate(Petal.Width2 = ifelse(Species == "setosa", Petal.Width * 75, Petal.Width))
p1 <- ggplot(data=iris, aes(x = factor(Species), y=Sepal.Width)) +
geom_bar(stat="identity") +
labs(x = NULL, y = "Plot One") +
scale_y_continuous(labels = percent) +
theme(axis.text.x = element_blank(),
axis.title.y = element_text(vjust=1), plot.margin=unit(c(2,2,0,2),"mm"))
p2 <- ggplot(data=iris, aes(x = factor(Species), y=Petal.Width2)) + geom_bar(stat="identity") +
labs(x = NULL, y = "Plot Two") +
scale_y_continuous(labels = percent) +
theme(axis.text.x = element_blank(),
axis.title.y = element_text(vjust=1), plot.margin=unit(c(0,2,0,2),"mm"))
p3 <- ggplot(data=iris, aes(x = factor(Species), y=Petal.Length*0+.01)) + geom_bar(stat="identity") +
labs(x = "SPECIES", y = "The Third plot") +
scale_y_continuous(labels = percent) +
theme( axis.title.y = element_text(vjust=1, color="blue"), plot.margin=unit(c(0,2,0,2),"mm"),
axis.text.x = element_text(angle = 90, hjust=1, vjust=1,face ="italic", size=10))
plot_grid(p1,p2,p3,ncol=1, align="v", labels=c("A", "B", "C"))
# https://stackoverflow.com/a/27408589/1670053
plots <- list(p1, p2, p3)
grobs = lapply(plots, ggplotGrob)
g = do.call(rbind, c(grobs, size="first"))
g$widths = do.call(unit.pmax, lapply(grobs, "[[", "widths"))
grid.newpage()
grid.draw(g)
it's easy as to add labels,
plots <- list(p1, p2, p3)
grobs = lapply(plots, ggplotGrob)
library(gridExtra)
g = do.call(rbind, grobs) # uses gridExtra::rbind.gtable
panels <- g$layout[g$layout$name=="panel",]
g <- gtable::gtable_add_grob(g, lapply(LETTERS[1:nrow(panels)],
textGrob, vjust=1, y=1,
gp=gpar(fontface=2)),
t=panels$t, l=2)
grid.newpage()
grid.draw(g)

Top to bottom alignment of two ggplot2 figures

I realize that the align.plots function from the ggExtra package has been deprecated and removed. However, I am using my own version as it seems to provide the specific functionality I need. I have looked into faceting to solve my problem but I don't think it will work for my particular issue. What seems to be the problem is that the top-to-bottom images don't align when I use coord_equal on one of them. This doesn't seem to affect left-to-right though. Here is a simplified (or at least as simple as I can make it) version of what I am trying to achieve.
Create some dummy data frames:
source('https://raw.github.com/jbryer/multilevelPSA/master/r/align.R')
require(psych)
df = data.frame(x=rnorm(100, mean=50, sd=10),
y=rnorm(100, mean=48, sd=10),
group=rep(letters[1:10], 10))
dfx = describe.by(df$x, df$group, mat=TRUE)[,c('group1', 'mean', 'n', 'min', 'max')]
names(dfx) = c('group', 'x', 'x.n', 'x.min', 'x.max')
dfy = describe.by(df$y, df$group, mat=TRUE)[,c('group1', 'mean', 'n', 'min', 'max')]
names(dfy) = c('group', 'y', 'y.n', 'y.min', 'y.max')
df2 = cbind(dfx, dfy[,2:ncol(dfy)])
range = c(0,100)
This will setup the three plots:
p1a = ggplot(df2, aes(x=x, y=y, colour=group)) + geom_point() +
opts(legend.position='none') +
scale_x_continuous(limits=range) + scale_y_continuous(limits=range)
p1 = p1a + coord_equal(ratio=1)
p2 = ggplot(df, aes(x=x, y=group, colour=group)) + geom_point() +
scale_x_continuous(limits=range) + opts(legend.position='none')
p3 = ggplot(df, aes(x=group, y=y, colour=group)) + geom_point() +
scale_y_continuous(limits=range) + opts(legend.position='none')
The alignment top to bottom does not work with coord_equal
grid_layout <- grid.layout(nrow=2, ncol=2, widths=c(1,2), heights=c(2,1))
grid.newpage()
pushViewport( viewport( layout=grid_layout, width=1, height=1 ) )
align.plots(grid_layout, list(p1, 1, 2), list(p3, 1, 1), list(p2, 2, 2))
Broken Plot http://bryer.org/alignplots1.png
The fix is to add respect=TRUE to the grid.layout call:
grid_layout <- grid.layout(nrow=2, ncol=2, widths=c(1,2), heights=c(2,1), respect=TRUE)
But if I don't use coord_equal the alignment works fine:
grid_layout <- grid.layout(nrow=2, ncol=2, widths=c(1,2), heights=c(2,1))
grid.newpage()
pushViewport( viewport( layout=grid_layout, width=1, height=1 ) )
align.plots(grid_layout, list(p1a, 1, 2), list(p3, 1, 1), list(p2, 2, 2))
Working Plot http://bryer.org/alignplots2.png
ggplot2 now has ggplotGrob(), which may help with this.
First, we need to update the code used to generate the plots:
p1a = ggplot(df2, aes(x=x, y=y, colour=group)) + geom_point() +
scale_x_continuous(limits=range) + scale_y_continuous(limits=range)
p1 = p1a + coord_equal(ratio=1) + theme_minimal() + theme(legend.position='none')
p2 = ggplot(df, aes(x=x, y=group, colour=group)) + geom_point() +
scale_x_continuous(limits=range) + theme_minimal() + theme(legend.position='none')
p3 = ggplot(df, aes(x=group, y=y, colour=group)) + geom_point() +
scale_y_continuous(limits=range) + theme_minimal() + theme(legend.position='none')
p4 <- ggplot(df, aes(x = group, y = y)) +
geom_blank() +
theme(line = element_blank(),
rect = element_blank(),
text = element_blank(),
title = element_blank())
p4 will be blank; we just need the grob to draw.
Then we load the grid package and draw the grobs in a list arranged in rows and columns using cbind() and rbind().
library(grid)
grid.newpage()
grid.draw(
cbind(
rbind(ggplotGrob(p3), ggplotGrob(p4), size = "first"),
rbind(ggplotGrob(p1), ggplotGrob(p2), size = "first"),
size = "first"))
I'm not sure if this method will let you plot p3 in a different width and p2 in a different height, as you have them in the original example; I normally need a grid of similarly-sized graphs, and haven't needed to figure out different sizes.
This answer is partially based on partially based on https://stackoverflow.com/a/17463184/393354
Here is an example:
m <- matrix(c(3, 1, 0, 2), 2, byrow = T)
lay <- gglayout(m, widths = c(1, 3), heights = c(3, 1))
ggtable(p1, p2, p3, layout = lay)
you can use this by
install.packages('devtools')
library(devtools)
dev_mode()
install_github("ggplot2", "kohske", "cutting-edge")
library(ggplot2)
note that this branch is experimental, so maybe there are bugs.
To solve the problem using the align.plots method, specify respect=TRUE on the layout call:
grid_layout <- grid.layout(nrow=2, ncol=2, widths=c(1,2), heights=c(2,1), respect=TRUE)

Resources