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GGplot2 is a popular data visualization package in R that allows users to create high-quality and customizable graphs. One of the key aspects of creating a visually appealing graph is adjusting the legend size. The legend refers to the key that explains the data represented in the graph. To change the legend size in ggplot2, users can use the “legend.text” and “legend.title” arguments within the “theme” function. This allows for precise control over both the text and title size in the legend. By adjusting these arguments, users can effectively change the legend size to best fit their graph and enhance its overall appearance.
Change Legend Size in ggplot2 (With Examples)
You can use the following syntax to change the size of elements in a ggplot2 legend:
ggplot(data, aes(x=x, y=y)) + theme(legend.key.size = unit(1, 'cm'), #change legend key size legend.key.height = unit(1, 'cm'), #change legend key heightlegend.key.width = unit(1, 'cm'), #change legend key width legend.title = element_text(size=14), #change legend title font sizelegend.text = element_text(size=10)) #change legend text font size
The following examples show how to use these arguments in practice.
Change ggplot2 Legend Key Size
Suppose we create the following grouped barplot using ggplot2:
library(ggplot2) #create data frame df <- data.frame(team=rep(c('A', 'B', 'C'), each=3), position=rep(c('Guard', 'Forward', 'Center'), times=3), points=c(14, 8, 8, 16, 3, 7, 17, 22, 26)) #create grouped barplot ggplot(df, aes(fill=position, y=points, x=team)) + geom_bar(position='dodge', stat='identity')
By default, ggplot2 provides a legend to the right of the graph.
The following code shows how to use the legend.key.size argument to make the keys of the legend larger:
ggplot(df, aes(fill=position, y=points, x=team)) + geom_bar(position='dodge', stat='identity') + theme(legend.key.size = unit(2, 'cm'))
We can also use the legend.key.width and legend.key.height arguments to specify widths and heights for the keys:
ggplot(df, aes(fill=position, y=points, x=team)) + geom_bar(position='dodge', stat='identity') + theme(legend.key.height= unit(2, 'cm'), legend.key.width= unit(4, 'cm'))
Change ggplot2 Legend Title Font Size
We can use the legend.title argument to make the legend title font size larger:
ggplot(df, aes(fill=position, y=points, x=team)) + geom_bar(position='dodge', stat='identity') + theme(legend.title = element_text(size=30))
Change ggplot2 Legend Text Font Size
We can use the legend.text argument to make the legend title font size larger:
ggplot(df, aes(fill=position, y=points, x=team)) + geom_bar(position='dodge', stat='identity') + theme(legend.text = element_text(size=30))
