如何使用geom_text在堆积条形图中显示值？

Question

我想在堆积条中显示百分比数字。但是，一组的百分比非常低。两个值彼此重叠。我改为'postion ='identity'。它仍然无法工作.....任何想法？

x4.can.m <- structure(list(canopy = structure(c(1L, 2L, 3L, 1L, 2L, 3L, 1L, 
2L, 3L, 1L, 2L, 3L, 1L, 2L, 3L), .Label = c("0%", "1 to 84%", 
"85% +"), class = "factor"), YearQuarter = structure(c(1L, 1L, 
1L, 2L, 2L, 2L, 3L, 3L, 3L, 4L, 4L, 4L, 5L, 5L, 5L), .Label = c("2011-09-01", 
"2011-12-01", "2012-03-01", "2012-06-01", "2012-09-01"), class = "factor"), 
    value = c(0.51, 0.01, 0.48, 0.52, 0.01, 0.47, 0.53, 0.01, 
    0.47, 0.57, 0.01, 0.41, 0.61, 0.01, 0.38)), .Names = c("canopy", 
"YearQuarter", "value"), row.names = c(NA, -15L), class = "data.frame")


x4.can.bar <- ggplot(data=x4.can.m, aes(x=factor(YearQuarter), y=value,fill=canopy)) + geom_bar(stat="identity",position = "stack",ymax=100)

x4.can.bar+scale_y_continuous(formatter='percent')+
 labs(y="Percentage",x="Year Quarter") + 
 geom_text(aes(label =paste(round(value*100,0),"%",sep="")),size = 3, hjust = 0.5, vjust = 4,position ="identity")

Answer 1

您需要为标签的展示位置指定合理的值 - 如果您在ggplot电话之外执行此操作，则会比在通话中尝试这样做容易得多。

您可以通过获取每个堆叠组件的中点来完成此操作。

使用plyr和ddply这是一个简单的方法，即获取累积总和并减去每个YearQuarter

中当前值的一半

library(plyr)
x4.can.m <- ddply(x4.can.m, .(YearQuarter), mutate, csum = cumsum(value)-value/2)

x4.can.bar <- ggplot(data=x4.can.m, aes(x=factor(YearQuarter), y=value,fill=canopy)) +  
 geom_bar(stat="identity",position = "stack",ymax=100)

x4.can.bar + 
 scale_y_continuous(expand = c(0,0), labels = percent) +
 labs(y="Percentage",x="Year Quarter")+
 geom_text(aes(y = csum,label =paste(round(value*100,0),"%",sep="")),
           size = 3, hjust = 1, vjust = 0)

请注意，我使用的是ggplot2_0.9.2.1，因此formatter不再是scale_y_continuous的有效参数，而是替换为label = percent。请参阅this question及相关链接

Answer 2

一种解决方案是将堆栈栏更改为闪避

x4.can.bar <- ggplot(data=x4.can.m, aes(x=factor(YearQuarter), y=value,fill=canopy)) + 
                    geom_bar(stat="identity",position = "dodge",ymax=100) +
             geom_text(aes(label =paste(round(value*100,0),"%",sep=""),ymax=0), 
                       position=position_dodge(width=0.9), vjust=-0.25)
x4.can.bar