ggplot在geom tile的每个tile中添加文本

Question

使用df下面的数据框

df <- data.frame(
  model=c(rep('corolla',3),rep( 'accord',3), rep('sunny',3)),
  variable=c('urban_mileage', 'rural_mileage', 'highway_mileage'),
  rescale=rnorm(9),
  year=c(rep(1998,3),rep( 1997,3), rep(2003,3)),
  kmdone=sample(10:100,9)*1e3
  )
> df
    model        variable     rescale year kmdone
1 corolla   urban_mileage -1.03675182 1998  56000
2 corolla   rural_mileage  1.06079162 1998  83000
3 corolla highway_mileage -0.18808551 1998  19000
4  accord   urban_mileage -0.05151496 1997  69000
5  accord   rural_mileage  0.05219512 1997  54000
6  accord highway_mileage -2.03139240 1997  21000
7   sunny   urban_mileage -0.06225862 2003  40000
8   sunny   rural_mileage  1.38191440 2003  96000
9   sunny highway_mileage -1.02367124 2003  55000
> 

我正在使用geom_tile创建一个热图,如下所示

ggplot(df, aes(variable, model)) + geom_tile(aes(fill = rescale), colour = "white") +
     scale_fill_gradient2(low = "red", mid = "white", high = "green") +
     labs(x = "",y = "") +
     theme(legend.title = element_blank(),
           axis.text.x = element_text(angle=30,hjust=1,vjust=1.0),
           axis.text.y = element_text(size = 12))

这给出了道路类型里程的热图表示,如最后的图像所示.

我需要用两件事来增强这一点

1. year在右轴上添加每个模型的标签(辅助y轴 - 尽管它不赞成:))
2. 显示kmdone每个图块内的值,如df中心文本中的黑色

Answer 1

两个小修改... paste(model,year)用于y审美,并添加geom_text如图所示......

ggplot(df, aes(variable, paste(model,year))) + geom_tile(aes(fill = rescale), colour = "white") + 
  geom_text(aes(label=kmdone)) +
  scale_fill_gradient2(low = "red", mid = "white", high = "green") +
  labs(x = "",y = "") +
  theme(legend.title = element_blank(),
        axis.text.x = element_text(angle=30,hjust=1,vjust=1.0),
        axis.text.y = element_text(size = 12))