Graphics for Statistics - figures with ggplot - Chapter 2 Part 2
Graphics for Statistics - Chapter 2 - Bar Charts: Figures 2.3-2.10 + 2.13
Graphics out of the book Graphics for Statistics and Data Analysis with R by Kevin Keen (book home page)
Bar charts of the United Nations budget for 2008-2009
mapping x to item1 and y to amount1
set stat="identity" because of presummarised data
and there is the basic plot
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(stat="identity")
ggsave("fig2_3.png")
But of course there is a lot to do left: you can not read the labels of the x-axis and the we have to change the axis titles
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(stat="identity") +
xlab("") +
ylab("Millions of US Dollars") +
opts(axis.text.x=theme_text(angle=90,size=12))
ggsave("fig2_3b.png")
and there is the graph in default ggplot style
now we the plot the style of the plot in the book:
add the expand argument to the definition of the y-axis to let the drawn axis end exactly at the limits
the width of the bins is changed through the width argument in geom_bar(); in this case it is a bit tricky, because using the identity stat resets width so we have to put width in to the aes() argument (further information)
we add a hjust argument in the axis.text.x to change the alignment
we set fill and colour of the background to white
we use a simple extension by Rudolf Cardinal (source line), because we want to remove just one axis not the two of them (further information)
and at the end like above, we use again the hack to get rid of the ticks of the x-axis
source("http://egret.psychol.cam.ac.uk/statistics/R/extensions/rnc_ggplot2_border_themes.r")
png("fig2_3c.png",height=500, width=500)
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800),expand=c(0,0)) +
xlab("") +
opts(axis.text.x=theme_text(angle=90,size=12,hjust=1),
axis.text.y=theme_text(size=12),
panel.background=theme_rect(fill="white",colour="white"),
panel.border=theme_left_border()
)
g <- grid.gget(gPath("axis-b", "", "", "", "axis.ticks.segments"))
grid.remove(g$name)
dev.off()
ggplot9.2 is out - and everything much easier:
you do not need to manipulate the grid elements directly, axis.ticks.x and axis.ticks.y are now available
there is also no need to use additional functions anymore: axis.line, axis.line.x and axis.line.y do a good job
maybe it this a bit confusing: first you have to set axis.line and then you you the axis blank you do not want to see, this is necessary because of the inheritance
there are also some functions renamed: use theme instead of opts and element instead of theme
## 9.2 version
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800),expand=c(0,0)) +
xlab("") +
theme(axis.text.x=element_text(angle=90,size=12,hjust=1,colour="black"),
axis.text.y=element_text(size=12,colour="black"),
axis.line=element_line(colour="black"),
axis.line.x=element_blank(),
axis.ticks.x=element_blank(),
panel.background=element_rect(fill="white",colour="white")
)
ggsave("fig2_3n.png")
in figure 2.4 just the angle of the labels is changed, but therefore we have to adjust the alignment (add vjust argument)
also set the size of the labels to 11
savePlot() is a alternative to open and close a device explicitly
source("http://egret.psychol.cam.ac.uk/statistics/R/extensions/rnc_ggplot2_border_themes.r")
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800)) +
xlab("") +
opts(axis.text.x=theme_text(angle=45,size=12,hjust=1,vjust=1),
axis.text.y=theme_text(size=12),
panel.background=theme_rect(fill="white",colour="white"),
panel.border=theme_left_border() )
g <- grid.gget(gPath("axis-b", "", "", "", "axis.ticks.segments"))
grid.remove(g$name)
savePlot("fig2_4.png")
and here is also the code for ggplot v9.2
## 9.2 version
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity") +
scale_y_continuous("Millions of US Dollars",expand=c(0,0),limits=c(0,800)) +
xlab("") +
theme(axis.text.x=element_text(angle=45,size=11,hjust=1,vjust=1,colour="black"),
axis.text.y=element_text(size=12,colour="black"),
axis.line=element_line(colour="black"),
axis.line.x=element_blank(),
axis.ticks.x=element_blank(),
panel.background=element_rect(fill="white",colour="white")
)
ggsave("fig2_4n.png")
in figure 2.5 the axes are exchanged - so we can use the final code from figure 2.3
and do some minor changes (alignment, angle of labels)
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800),expand=c(0,0)) +
xlab("") +
coord_flip() +
opts(axis.text.x=theme_text(size=11,vjust=-1),
axis.text.y=theme_text(hjust=1,size=12),
panel.background=theme_rect(fill="white",colour="white"),
panel.border=theme_bottom_border()
)
g <- grid.gget(gPath("axis-l", "", "", "", "axis.ticks.segments"))
grid.remove(g$name)
savePlot("fig2_5.png")
and here is the 9.2 version
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800),expand=c(0,0)) +
xlab("") +
coord_flip() +
theme(axis.text.x=element_text(size=11,vjust=-1,colour="black"),
axis.text.y=element_text(hjust=1,size=12,colour="black"),
axis.line=element_line(colour="black"),
axis.line.y=element_blank(),
axis.ticks.y=element_blank(),
axis.ticks.x=element_line(colour="black"),
panel.background=element_rect(fill="white",colour="white")
)
ggsave("fig2_5n.png")
for figure 2.6 we just remove the colour argument from panel.background, the panel.border option and add panel.grid.major=theme_blank() to get rid of the tracks of the grid lines
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800),expand=c(0,0)) +
xlab("") +
coord_flip() +
opts(axis.text.x=theme_text(size=11,vjust=-1),
axis.text.y=theme_text(hjust=1,size=12),
panel.background=theme_rect(fill="white"),
panel.grid.major=theme_blank()
)
g <- grid.gget(gPath("axis-l", "", "", "", "axis.ticks.segments"))
grid.remove(g$name)
savePlot("fig2_6.png")
and again the 9.2 version
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800),expand=c(0,0)) +
xlab("") +
coord_flip() +
theme(axis.text.x=element_text(size=11,vjust=-1,colour="black"),
axis.text.y=element_text(hjust=1,size=12,colour="black"),
axis.ticks.y=element_blank(),
axis.ticks.x=element_line(colour="black"),
panel.background=element_rect(fill="white",colour="black"),
panel.grid.major=element_blank()
)
ggsave("fig2_6n.png")
from now all code is for ggplot2 version 9.2
figure 2.8 keep the vertical grid lines, but removes the horizontal ones: this is controlled by panel.grid.major.x and panel.grid.major.y (line elements)
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800),expand=c(0,0)) +
xlab("") +
coord_flip() +
theme(axis.text.x=element_text(size=11,vjust=-1,colour="black"),
axis.text.y=element_text(hjust=1,size=12,colour="black"),
axis.ticks.y=element_blank(),
axis.ticks.x=element_line(colour="black"),
panel.background=element_rect(fill="white",colour="black"),
panel.grid.major.y=element_blank(),
panel.grid.major.x=element_line(colour="black")
)
ggsave("fig2_8.png")
for figure 2.9 we change the colour of the borders of the bars to black (colour) and the colour of the filling to grey (fill)
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity",fill="grey",colour="black") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800),expand=c(0,0)) +
xlab("") +
coord_flip() +
theme(axis.text.x=element_text(size=12,colour="black"),
axis.text.y=element_text(size=12,colour="black"),
axis.ticks.x=element_line(colour="black"),
axis.ticks.y=element_blank(),
axis.ticks.x=element_line(colour="black"),
axis.line=element_line(colour="black"),
axis.line.y=element_blank(),
panel.background=element_rect(fill="white")
)
ggsave("fig2_9.png")
for figure 2.10 just the filling of the bars have to be changed to white
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity",fill="white",colour="black") +
scale_y_continuous("Millions of US Dollars",limits=c(0,800),expand=c(0,0)) +
xlab("") +
coord_flip() +
theme(axis.text.x=element_text(size=12,colour="black"),
axis.text.y=element_text(size=12,colour="black"),
axis.ticks.x=element_line(colour="black"),
axis.ticks.y=element_blank(),
axis.ticks.x=element_line(colour="black"),
axis.line=element_line(colour="black"),
axis.line.y=element_blank(),
panel.background=element_rect(fill="white")
)
ggsave("fig2_10.png")
for figure 2.13 figure 2.4 is a good beginning
set the colour of the filling of the bars to grey
we set the breaks and labels of the y-axis manually
add horizontal white lines via geom_hline
## 2.13
dollars <- paste("US$",c(200,400,600),"k",sep="")
ggplot(df,aes(x=item1,y=amount1)) +
geom_bar(aes(width=0.7),stat="identity",fill="grey") +
scale_y_continuous(expand=c(0,0),breaks=c(0,200,400,600),labels=c("0",dollars)) +
geom_hline(yintercept=c(200,400,600),colour="white") +
theme(axis.text=element_text(size=11.5,colour="black"),
axis.text.x=element_text(angle=45,hjust=1,vjust=1),
axis.ticks=element_blank(),
axis.title=element_blank(),
axis.line=element_line(colour="grey"),
axis.line.y=element_blank(),
panel.background=element_rect(fill="white",colour="white")
)
ggsave("fig2_13.png")
