使用來自兩個數據框的數據向條形圖添加圖例

Question

我有兩個圖，我只想知道如何為藍色和灰色條形圖添加圖例，你能告訴我如何編輯圖例標題嗎？

X1 <- c(seq(7.912087912,44.83516484,1.538461538))
X2 <- c(seq(7.912087912,49.45054945,1.538461538))

dat2 <- data.frame(x = X2 , y = rnorm(28, 26, 5))

dat1 <- data.frame(x = X1 , y =  rnorm(100, 25, 4))

ggplot(NULL)  +
  geom_bar(dat1, mapping = aes(x = x, y = y), stat = "identity",alpha = 0.3, position = "stack" ) + labs( x = " Time [ S ]", y = "Frequency") + theme_minimal() +
  ggtitle("Histogram Of Time In Tank") + theme(plot.title = element_text(hjust = 0.5)) +
  theme(plot.title = element_text(hjust = 0.5)) +
  geom_bar(dat2, mapping = aes(x = x, y = y  ), stat = "identity", alpha = .3, position = "stack", fill='lightblue' , color='lightblue4')  
+ scale_linetype_discrete(name = LegendTitle)

Answer 1

如果你想要 ggplot 中的圖例，你需要在你的aes()中有一個美學映射，否則不會出現圖例。 下面是我們如何設置一個映射，然后使用比例來設置我們想要的 colors

ggplot(NULL)  +
  geom_bar(dat1, mapping = aes(x = x, y = y, fill="Grey Bars"), stat = "identity",alpha = 0.3, position = "stack" ) + 
  labs( x = " Time [ S ]", y = "Frequency") + 
  theme_minimal() +
  ggtitle("Histogram Of Time In Tank") + 
  theme(plot.title = element_text(hjust = 0.5)) +
  geom_bar(dat2, mapping = aes(x = x, y = y, fill='Blue Bars') , stat = "identity", alpha = .3, position = "stack", color='lightblue4')  +
  scale_fill_manual(name="Bars", values=c("Grey Bars" = "grey35", "Blue Bars" = "lightblue"))