如何在 ggplot 中调整 geom_text 在 geom_bar 列上的位置？

Question

我正在尝试在 ggplot2 中制作一个条形图，但是当我添加标签时，它们聚集在一个中间条上，而不是坐在值本身代表的条上。

我正在使用的代码：

synch<-data.frame(Species = c("AMCO","AMCO","AMCO","GADW","GADW","GADW","AGWT","AGWT","AGWT","RNDU","RNDU","RNDU"),
                  Value=c(93.3,61.1,97.4,0.8,34.9,0.2,0.0,4.0,0.0,0.5,0.0,0.4),
                  SurveyType=c("A","B","C","A","B","C","A","B","C","A","B","C"))
synch
library(dplyr)
library(ggplot2)
synchAMCO = synch %>% filter(Species == "AMCO")
synchGADW = synch %>% filter(Species == "GADW")
synchAGWT = synch %>% filter(Species == "AGWT")
synchRNDU = synch %>% filter(Species == "RNDU")

synchplot.again<- ggplot(data=synch) +
  geom_bar(data = synchAMCO, 
           mapping = aes(x = Species, y = Value, fill = SurveyType), 
           stat='identity', position = position_dodge(width = 0.75), width=0.7) + theme_bw() + 
  scale_fill_manual(name = "Survey Type", 
                    labels = c("UAV Pre-plane","Plane","UAV Post-plane"),
                    values = c("darkblue","red","lightblue"),
                    aesthetics = "fill") +
  theme(legend.text = element_text(size = 10, family = "Arial", colour = "black")) +
  new_scale_fill() + 
  geom_bar(data = synchGADW, 
           mapping = aes(x = Species, y = Value, fill = SurveyType), 
           stat='identity', position = position_dodge(width = 0.75), width=0.7,show.legend = FALSE) +
  scale_fill_manual(name = "GADW", 
                    labels = c("UAV Pre-plane","Plane","UAV Post-plane"),
                    values = c("darkblue","red","lightblue"),
                    aesthetics = "fill")+
  new_scale_fill() + 
  geom_bar(data = synchAGWT, 
           mapping = aes(x = Species, y = Value, fill = SurveyType), 
           stat='identity', position = position_dodge(width = 0.75), width=0.7,show.legend = FALSE) +
  scale_fill_manual(name = "AGWT", 
                    labels = c("UAV Pre-plane","Plane","UAV Post-plane"),
                    values = c("darkblue","red","lightblue"),
                    aesthetics = "fill")+
  new_scale_fill() + 
  geom_bar(data = synchRNDU, 
           mapping = aes(x = Species, y = Value, fill = SurveyType), 
           stat='identity', position = position_dodge(width = 0.75), width=0.7,show.legend = FALSE) +
  scale_fill_manual(name = "RNDU", 
                    labels = c("UAV Pre-plane","Plane","UAV Post-plane"),
                    values = c("darkblue","red","lightblue"),
                    aesthetics = "fill") +
  geom_text(position = position_dodge(width = 0.75), 
            aes(x = Species, y = Value+2, label = Value))+
  theme(plot.title = element_text(hjust = 0.5)) +
  theme(panel.border = element_blank(), panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(), 
        axis.line = element_line(colour = "black"),
        text = element_text(size = 16,
                            family = "Arial"))+
  labs(y="Proportion of Count") +
  ggtitle("Species Proportion of Total Survey Count by Survey Type - 
            Swan Creek Dewatering Unit, Late Season") + 
  theme(legend.title = element_text(size = 12, family = "Arial")) +
  theme(plot.title = element_text(size = 15, family = "Arial")) 

synchplot.again

这是结果图：

我只是希望标签位于各自的栏上。

我已经多次看到这个问题被问和回答，并且我已经尝试了每个不同答案中的代码。我有这三个问题链接如下：

1. 如何使用ggplot2在R中将标签放在geom_bar上
2. geom_text 标签栏不正确
3. ggplot geom_text 不位于条形顶部

这些都讨论了调整 geom_text 创建的标签位置的不同方法，但它们都不适合我。 有什么建议么？ 预先感谢您。

Answer 1

您需要将

group = SurveyType

添加到

aes()

geom_text()

以实现文本标签的正确放置。

此外，您可以简化代码，因为您不需要引入 带有

ggnewscale::new_scale_fill()

的新音阶，您无需准备

synch

data.frame

的子集。

library(dplyr)
library(ggplot2)

ggplot(data = synch) +
  geom_bar(
    mapping = aes(x = Species, y = Value, fill = SurveyType),
    stat = 'identity',
    position = position_dodge(width = 0.75),
    width = 0.7
  ) + theme_bw() +
  scale_fill_manual(
    name = "Survey Type",
    labels = c("UAV Pre-plane", "Plane", "UAV Post-plane"),
    values = c("darkblue", "red", "lightblue"),
    aesthetics = "fill"
  ) +
  geom_text(aes(
    x = Species,
    y = Value + 2,
    label = Value,
    group = SurveyType
  ),
  position = position_dodge(width = 0.75)) +
  theme(
    legend.title = element_text(size = 12, family = "Arial"),
    legend.text = element_text(
      size = 10,
      family = "Arial",
      colour = "black"
    ),
    plot.title = element_text(hjust = 0.5),
    panel.border = element_blank(),
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank(),
    axis.line = element_line(colour = "black"),
    text = element_text(size = 16,
                        family = "Arial")
  ) +
  labs(y = "Proportion of Count") +
  ggtitle(
    "Species Proportion of Total Survey Count by Survey Type -
          Swan Creek Dewatering Unit, Late Season"
  )