I’m very pleased to announce ggplot2 2.2.0. It includes four major new features:
- Subtitles and captions.
- A large rewrite of the facetting system.
- Improved theme options.
- Better stacking.
It also includes as numerous bug fixes and minor improvements, as described in the release notes.
The majority of this work was carried out by Thomas Pederson, who I was lucky to have as my “ggplot2 intern” this summer. Make sure to check out his other visualisation packages: ggraph, ggforce, and tweenr.
Install ggplot2 with:
The facet and layout implementation has been moved to ggproto and received a large rewrite and refactoring. This will allow others to create their own facetting systems, as descrbied in the
vignette("extending-ggplot2"). Along with the rewrite a number of features and improvements has been added, most notably:
- ou can now use functions in facetting formulas, thanks to Dan Ruderman.
ggplot(diamonds, aes(carat, price)) + geom_hex(bins = 20) + facet_wrap(~cut_number(depth, 6))
- Axes are now drawn under the panels in
facet_wrap()when the rentangle is not completely filled.
ggplot(mpg, aes(displ, hwy)) + geom_point() + facet_wrap(~class)
- You can set the position of the axes with the
ggplot(mpg, aes(displ, hwy)) + geom_point() + scale_x_continuous(position = "top") + scale_y_continuous(position = "right")
- You can display a secondary axis that is a one-to-one transformation of the primary axis with
ggplot(mpg, aes(displ, hwy)) + geom_point() + scale_y_continuous( "mpg (US)", sec.axis = sec_axis(~ . * 1.20, name = "mpg (UK)") )
- Strips can be placed on any side, and the placement with respect to axes can be controlled with the
ggplot(mpg, aes(displ, hwy)) + geom_point() + facet_wrap(~ drv, strip.position = "bottom") + theme( strip.placement = "outside", strip.background = element_blank(), strip.text = element_text(face = "bold") ) + xlab(NULL)
theme()function now has named arguments so autocomplete and documentation suggestions are vastly improved.
- Blank elements can now be overridden again so you get the expected behavior when setting e.g.
arrowargument that lets you put arrows on axes.
arrow <- arrow(length = unit(0.4, "cm"), type = "closed") ggplot(mpg, aes(displ, hwy)) + geom_point() + theme_minimal() + theme( axis.line = element_line(arrow = arrow) )
- Control of legend styling has been improved. The whole legend area can be aligned with the plot area and a box can be drawn around all legends:
ggplot(mpg, aes(displ, hwy, shape = drv, colour = fl)) + geom_point() + theme( legend.justification = "top", legend.box = "horizontal", legend.box.margin = margin(3, 3, 3, 3, "mm"), legend.margin = margin(), legend.box.background = element_rect(colour = "grey50") )
legend.marginhave been renamed to
legend.spacingrespectively, as this better indicates their roles. A new
legend.marginactually controls the margin around each legend.
- When computing the height of titles, ggplot2 now inclues the height of the descenders (i.e. the bits
ythat hang underneath). This improves the margins around titles, particularly the y axis label. I have also very slightly increased the inner margins of axis titles, and removed the outer margins.
- The default themes has been tweaked by Jean-Olivier Irisson making them better match
position_fill() now stack values in the reverse order of the grouping, which makes the default stack order match the legend.
avg_price <- diamonds %>% group_by(cut, color) %>% summarise(price = mean(price)) %>% ungroup() %>% mutate(price_rel = price - mean(price)) ggplot(avg_price) + geom_col(aes(x = cut, y = price, fill = color))
(Note also the new
geom_col() which is short-hand for
geom_bar(stat = "identity"), contributed by Bob Rudis.)
If you want to stack in the opposite order, try
ggplot(avg_price) + geom_col(aes(x = cut, y = price, fill = fct_rev(color)))
Additionally, you can now stack negative values:
ggplot(avg_price) + geom_col(aes(x = cut, y = price_rel, fill = color))
The overall ordering cannot necessarily be matched in the presence of negative values, but the ordering on either side of the x-axis will match.
Labels can also be stacked, but the default position is suboptimal:
series <- data.frame( time = c(rep(1, 4),rep(2, 4), rep(3, 4), rep(4, 4)), type = rep(c('a', 'b', 'c', 'd'), 4), value = rpois(16, 10) ) ggplot(series, aes(time, value, group = type)) + geom_area(aes(fill = type)) + geom_text(aes(label = type), position = "stack")
You can improve the position with the
vjust parameter. A
vjust of 0.5 will center the labels inside the corresponding area:
ggplot(series, aes(time, value, group = type)) + geom_area(aes(fill = type)) + geom_text(aes(label = type), position = position_stack(vjust = 0.5))