add a common border for combined ggplots - r

Question

I would like to add a common border for the combined pie charts. When I use panel_border() the left and bottom lines appear as more darker than upper and right lines. I couldn't figure out my mistake.1) How can I add a common border for combined plots?
2) How can I reduce the thickness of left and bottom lines?
df1 <- data.frame(
variable = c("china","korea","canada","UK","USA"),
value = c(1632,1320,4491,991,620)
)
df2 <- data.frame(
variable = c("china","korea","canada","UK","USA"),
value = c(7376,1770,5210,5005,3947)
)
library(ggplot2)
p1 <-ggplot(df1,aes(x="", y = value, fill = variable))+ geom_bar(stat="identity", width=1) + ggtitle("Rainfall - 2014")+ panel_border() +coord_polar(theta = "y")+xlab("")+ylab("")+theme(legend.position="right", legend.title=element_blank(), plot.title = element_text(lineheight=3, face="bold", color="black", size=14))
p2 <-ggplot(df2,aes(x="", y = value, fill = variable))+ geom_bar(stat="identity", width=1) + ggtitle("Rainfall - 2015")+panel_border() +coord_polar(theta = "y")+xlab("")+ylab("")+theme(legend.position="right", legend.title=element_blank(), plot.title = element_text(lineheight=3, face="bold", color="black", size=14))
library(cowplot)
plot_grid(p1, p2, labels=c("A", "B" ))

Answer 1

Sanu,
The first component of the problem is that you are not seeing a border your are seeing the axis.line, and axis.text theme attributes. You need to remove these from the theme by applying element_blank() to both...
library(ggplot2)
library(cowplot)
df1 <- data.frame(
variable = c("china","korea","canada","UK","USA"),
value = c(1632,1320,4491,991,620)
)
df2 <- data.frame(
variable = c("china","korea","canada","UK","USA"),
value = c(7376,1770,5210,5005,3947)
)
p1 <-ggplot(df1, aes(x="", y = value, fill = variable))
p1 <- p1 + geom_bar(stat="identity", width=1)
p1 <- p1 + ggtitle("Rainfall - 2014")
# p1 <- p1 + panel_border()
p1 <- p1 + coord_polar(theta = "y")
p1 <- p1 + xlab("")
p1 <- p1 + ylab("")
p1 <- p1 + theme(legend.position="right",
legend.title=element_blank(),
axis.line=element_blank(),
axis.ticks=element_blank(), # the axis ticks
plot.title = element_text(lineheight=3, face="bold", color="black", size=14))
p2 <-ggplot(df2,aes(x="", y = value, fill = variable))
p2 <- p2 + geom_bar(stat="identity", width=1)
p2 <- p2 + ggtitle("Rainfall - 2015")
# p2 <- p2 + panel_border()
p2 <- p2 + coord_polar(theta = "y")
p2 <- p2 + xlab("")
p2 <- p2 + ylab("")
p2 <- p2 + theme( legend.position="right",
legend.title = element_blank(),
axis.line=element_blank(),
axis.ticks=element_blank(), # the axis ticks
plot.title = element_text(lineheight=3, face="bold", color="black", size=14))
plot_grid(p1, p2, labels=c("A", "B" ))
result:
a better solution might be to clean up the plot as follows:
library(gridExtra)
get_legend<-function(myggplot){
tmp <- ggplot_gtable(ggplot_build(myggplot))
leg <- which(sapply(tmp$grobs, function(x) x$name) == "guide-box")
legend <- tmp$grobs[[leg]]
return(legend)
}
legend <- get_legend(p1)
p1 <- p1 + theme(legend.position="none")
p2 <- p2 + theme(legend.position="none")
# Arrange ggplot2 graphs with a specific width
grid.arrange(p1, p2, legend, ncol=3, widths=c(2.3, 2.3, 0.8))
result:
and now we add the border by adding...
# next line adds border
grid.rect(.5,.5,width=unit(.99,"npc"), height=unit(0.99,"npc"),
gp=gpar(lwd=3, fill=NA, col="black"))
thus:
to remove the axis test we add axis.text.x=element_blank() to the theme definition... Thus:
library(ggplot2)
library(cowplot)
df1 <- data.frame(
variable = c("china","korea","canada","UK","USA"),
value = c(1632,1320,4491,991,620)
)
df2 <- data.frame(
variable = c("china","korea","canada","UK","USA"),
value = c(7376,1770,5210,5005,3947)
)
p1 <-ggplot(df1, aes(x="", y = value, fill = variable))
p1 <- p1 + geom_bar(stat="identity", width=1)
p1 <- p1 + ggtitle("Rainfall - 2014")
# p1 <- p1 + panel_border()
p1 <- p1 + coord_polar(theta = "y")
p1 <- p1 + xlab("")
p1 <- p1 + ylab("")
p1 <- p1 + theme(legend.position="right",
legend.title=element_blank(),
axis.line=element_blank(),
axis.ticks=element_blank(), # the axis ticks
axis.text.x=element_blank(),
plot.title = element_text(lineheight=3, face="bold", color="black", size=14))
p1
p2 <-ggplot(df2,aes(x="", y = value, fill = variable))
p2 <- p2 + geom_bar(stat="identity", width=1)
p2 <- p2 + ggtitle("Rainfall - 2015")
# p2 <- p2 + panel_border()
p2 <- p2 + coord_polar(theta = "y")
p2 <- p2 + xlab("")
p2 <- p2 + ylab("")
p2 <- p2 + theme( legend.position="right",
legend.title = element_blank(),
axis.line=element_blank(),
axis.ticks=element_blank(), # the axis ticks
axis.text.x=element_blank(),
plot.title = element_text(lineheight=3, face="bold", color="black", size=14))
plot_grid(p1, p2, labels=c("A", "B" ))
library(gridExtra)
get_legend<-function(myggplot){
tmp <- ggplot_gtable(ggplot_build(myggplot))
leg <- which(sapply(tmp$grobs, function(x) x$name) == "guide-box")
legend <- tmp$grobs[[leg]]
return(legend)
}
legend <- get_legend(p1)
p1 <- p1 + theme(legend.position="none")
p2 <- p2 + theme(legend.position="none")
# 4. Arrange ggplot2 graphs with a specific width
grid.arrange(p1, p2, legend, ncol=3, widths=c(2.3, 2.3, 0.8))
# next line adds border
grid.rect(.5,.5,width=unit(.99,"npc"), height=unit(0.99,"npc"),
gp=gpar(lwd=3, fill=NA, col="black"))
result: