ggplo2在R：geom_segment显示不同的线比geom_line

Question

说我有此数据帧：

treatment <- c(rep("A",6),rep("B",6),rep("C",6),rep("D",6),rep("E",6),rep("F",6)) 
year <- as.numeric(c(1999:2004,1999:2004,2005:2010,2005:2010,2005:2010,2005:2010)) 
variable <- c(runif(6,4,5),runif(6,5,6),runif(6,3,4),runif(6,4,5),runif(6,5,6),runif(6,6,7)) 
se <- c(runif(6,0.2,0.5),runif(6,0.2,0.5),runif(6,0.2,0.5),runif(6,0.2,0.5),runif(6,0.2,0.5),runif(6,0.2,0.5)) 
id <- 1:36 
df1 <- as.data.table(cbind(id,treatment,year,variable,se)) 

df1$year <- as.numeric(df1$year) 
df1$variable <- as.numeric(df1$variable) 
df1$se <- as.numeric(df1$se) 

正如我在以前的问题（draw two lines with the same origin using ggplot2 in R）提到的，我想用GGPLOT2在一个特定的显示我的数据办法。

我设法做到使用下面的脚本：

y1 <- df1[df1$treatment=='A'&df1$year==2004,]$variable 
y2 <- df1[df1$treatment=='B'&df1$year==2004,]$variable 
y3 <- df1[df1$treatment=='C'&df1$year==2005,]$variable 
y4 <- df1[df1$treatment=='D'&df1$year==2005,]$variable 
y5 <- df1[df1$treatment=='E'&df1$year==2005,]$variable 
y5 <- df1[df1$treatment=='E'&df1$year==2005,]$variable 
y6 <- df1[df1$treatment=='F'&df1$year==2005,]$variable 

p <- ggplot(df1,aes(x=year,y=variable,group=treatment,color=treatment))+ 
geom_line(aes(y = variable, group = treatment, linetype = treatment, color = treatment),size=1.5,lineend = "round") + 
scale_linetype_manual(values=c('solid','solid','solid','dashed','solid','dashed')) + 
geom_point(aes(colour=factor(treatment)),size=4)+ 
geom_errorbar(aes(ymin=variable-se,ymax=variable+se),width=0.2,size=1.5)+ 
guides(colour = guide_legend(override.aes = list(shape=NA,linetype = c("solid", "solid",'solid','dashed','solid','dashed')))) 

p+labs(title="Title", x="years", y = "Variable 1")+ 
    theme_classic() + 
scale_x_continuous(breaks=c(1998:2010), labels=c(1998:2010),limits=c(1998.5,2010.5))+ 
    geom_segment(aes(x=2004, y=y1, xend=2005, yend=y3),colour='blue1',size=1.5,linetype='solid')+ 
    geom_segment(aes(x=2004, y=y1, xend=2005, yend=y4),colour='blue1',size=1.5,linetype='dashed')+ 
    geom_segment(aes(x=2004, y=y2, xend=2005, yend=y5),colour='red3',size=1.5,linetype='solid')+ 
    geom_segment(aes(x=2004, y=y2, xend=2005, yend=y6),colour='red3',size=1.5,linetype='dashed')+ 
    scale_color_manual(values=c('blue1','red3','blue1','blue1','red3','red3'))+ 
    theme(text = element_text(size=12)) 

正如你可以看到我同时使用geom_line和geom_segment以显示我的图线。

这几乎是完美的，但如果你仔细观察，要绘制的（2004年和2005年之间）的部分不显示在同一行的大小，尽管我用的脚本相同的参数值（即size=1.5和linetype='solid'或dashed）。

当然，我可以手动更改段的大小以获得相似的线条，但是当我这样做时，线段不如使用geom_line的线条那样流畅。 另外，通过在aes()参数中包含size或linetype参数，我会遇到同样的问题（不同的线条形状）。

你有什么想法是什么导致了这种差异，我怎么能得到完全相同的形状为我的段和线？

Answer 1

它似乎是一个geom_segment反锯齿问题，但这似乎是一个有点麻烦的方法开始。我想我已经通过在原始数据框中复制A和B治疗来解决您的问题。

# First we are going to duplicate and rename the 'shared' treatments 
library(dplyr) 
library(ggplot2) 

df1 %>% 
    filter(treatment %in% c("A", "B")) %>% 
    mutate(treatment = ifelse(treatment == "A", 
          "AA", "BB")) %>% 
    bind_rows(df1) %>% # This rejoins with the original data 
    # Now we create `treatment_group` and `line_type` variables 
    mutate(treatment_group = ifelse(treatment %in% c("A", "C", "D", "AA"), 
            "treatment1", 
            "treatment2"), # This variable will denote color 
     line_type = ifelse(treatment %in% c("AA", "BB", "D", "F"), 
          "type1", 
          "type2")) %>% # And this variable denotes the line type 

# Now pipe into ggplot 
    ggplot(aes(x = year, y = variable, 
      group = interaction(treatment_group, line_type), # grouping by both linetype and color 
      color = treatment_group)) + 
    geom_line(aes(x = year, y = variable, linetype = line_type), 
      size = 1.5, lineend = "round") + 
    geom_point(size=4) + 
    # The rest here is more or less the same as what you had 
    geom_errorbar(aes(ymin = variable-se, ymax = variable+se), 
       width = 0.2, size = 1.5) + 
    scale_color_manual(values=c('blue1','red3')) + 
    scale_linetype_manual(values = c('dashed', 'solid')) + 
    labs(title = "Title", x = "Years", y = "Variable 1") + 
    scale_x_continuous(breaks = c(1998:2010), 
        limits = c(1998.5, 2010.5))+ 
    theme_classic() + 
    theme(text = element_text(size=12)) 

它会给你以下

我的号码是不同的，因为他们是随机生成的。

然后，您可以根据自己的喜好修改图例，但我的建议是使用类似geom_label的东西，然后一定要设置check_overlap = TRUE。

希望这会有所帮助！