ggplot2中误差条的宽度

Question

我有一些数据与标准错误相关联,并希望显示这些错误栏.这就是我的意思:

# generate some data
hod <- data.frame(h = c(1:24,1:24,1:24), mean = 1:(24*3) + runif(24*3, 0, 5),ci = runif(24*3, 0, 2), t = c(rep("a",24),rep("b",24),rep("c",24)))

pd <- position_dodge(0.3)
  dayplot <- ggplot(hod, aes(x=h, y=mean, colour=as.factor(t),group=as.factor(t))) + 
    geom_line(position=pd, size=1) +
    geom_errorbar(aes(ymin=mean-ci, ymax=mean+ci),
                  width=1,
                  size=0.5,
                  position=pd) +
    geom_point(position=pd, shape=21, size=1, fill="white") +
    scale_x_continuous(limits=c(-0.5,23.5),
                       breaks=c(0:8*3),
                       labels=ifelse(
                              c(0:8*3) < 10,
                              paste('0',c(0:8*3),':00',sep=''),
                              paste(c(0:8*3),':00',sep='')
                              )
                       ) +
    xlab("Hour of day") + ylab(ylabel) + labs(title = varlabels[var]) +
    theme_minimal() + 
    theme(plot.margin = unit(c(1,0,1,1), "cm"), 
          axis.title.x = element_text(vjust=-1),
          axis.title.y = element_text(angle=90, vjust=0),
          legend.margin = unit(c(0), "cm"),
          legend.key.height = unit(c(0.9), "cm"),
          panel.grid.major = element_line(colour=rgb(0.87,0.87,0.87)),
          panel.grid.minor = element_blank(),
          plot.background = element_rect(fill = rgb(0.97,0.97,0.97), linetype=0)
    )

唯一感兴趣的可能是:

geom_errorbar(aes(ymin=mean-ci, ymax=mean+ci),
                      width=1,
                      size=0.5,
                      position=pd)

它给:

现在当我用因子变量(as.factor(t))对数据进行分组时,我得到了几行而不是一行,这就是我想要的,但是,正如你所看到的,误差条上的水平线更窄,我不能找出原因.我试图改变,甚至带走width和size属性geom_errorbar,但没有任何反应.有没有办法让每个图表的水平线宽度相同,无论数据是什么？我的意思是,它为什么要变化？或者这个宽度是否传达了一些信息？

Answer 1

以下是使用随机数据的可重现示例.解决问题的方法是将宽度乘以您拥有的类/因子数.在下面的图中,由于我使用了三个因子,使用宽度为3可以解决问题.ggplot2似乎通过数据集中的数据点数来计算相对宽度,而不是x轴上的数值.这是(IMO)的一个错误.

library(ggplot2)
library(grid)

#plot with factors
hod <- data.frame(h = c(1:24,1:24,1:24), mean = 1:(24*3) + runif(24*3, 0, 5),ci = runif(24*3, 0, 2), t = c(rep("a",24),rep("b",24),rep("c",24)))
pd <- position_dodge(0.3)
  dayplot <- ggplot(hod, aes(x=h, y=mean, colour=as.factor(t),group=as.factor(t))) + 

    geom_line(position=pd, size=1) +
    geom_errorbar(aes(ymin=mean-ci, ymax=mean+ci),
                  width=1,
                  size=0.5,
                  position=pd) +
    geom_point(position=pd, shape=21, size=1, fill="white") +
    scale_x_continuous(limits=c(-0.5,23.5),
                       breaks=c(0:8*3),
                       labels=ifelse(
                              c(0:8*3) < 10,
                              paste('0',c(0:8*3),':00',sep=''),
                              paste(c(0:8*3),':00',sep='')
                              )
                       ) +
    xlab("Hour of day") +
    theme_minimal() + 
    theme(plot.margin = unit(c(1,0,1,1), "cm"), 
          axis.title.x = element_text(vjust=-1),
          axis.title.y = element_text(angle=90, vjust=0),
          legend.margin = unit(c(0), "cm"),
          legend.key.height = unit(c(0.9), "cm"),
          panel.grid.major = element_line(colour=rgb(0.87,0.87,0.87)),
          panel.grid.minor = element_blank(),
          plot.background = element_rect(fill = rgb(0.97,0.97,0.97), linetype=0)
    )
print(dayplot)


#plot without factors
hod <- data.frame(h = c(1:24,1:24,1:24), mean = 1:(24) + runif(24, 0, 5),ci = runif(24, 0, 2))
pd <- position_dodge(0.3)
  dayplot <- ggplot(hod, aes(x=h, y=mean)) + 

    geom_line(position=pd, size=1) +
    geom_errorbar(aes(ymin=mean-ci, ymax=mean+ci),
                  width=1,
                  size=0.5,
                  position=pd) +
    geom_point(position=pd, shape=21, size=1, fill="white") +
    scale_x_continuous(limits=c(-0.5,23.5),
                       breaks=c(0:8*3),
                       labels=ifelse(
                              c(0:8*3) < 10,
                              paste('0',c(0:8*3),':00',sep=''),
                              paste(c(0:8*3),':00',sep='')
                              )
                       ) +
    xlab("Hour of day") +
    theme_minimal() + 
    theme(plot.margin = unit(c(1,0,1,1), "cm"), 
          axis.title.x = element_text(vjust=-1),
          axis.title.y = element_text(angle=90, vjust=0),
          legend.margin = unit(c(0), "cm"),
          legend.key.height = unit(c(0.9), "cm"),
          panel.grid.major = element_line(colour=rgb(0.87,0.87,0.87)),
          panel.grid.minor = element_blank(),
          plot.background = element_rect(fill = rgb(0.97,0.97,0.97), linetype=0)
    )

print(dayplot)