R ggplot2 ggrepel - 在知道所有点的同时标记点的子集

Question

我有一个相当密集的散点图,我用R'ggplot2'构建,我想用'ggrepel'标记一个点的子集.我的问题是我想在散点图中绘制所有点,但只用ggrepel标记一个子集,当我这样做时,ggrepel在计算放置标签的位置时没有考虑图上的其他点,这导致与图上其他点重叠的标签(我不想标记).

这是一个说明问题的示例图.

# generate data:
library(data.table)
library(stringi)
set.seed(20180918)
dt = data.table(
  name = stri_rand_strings(3000,length=6),
  one = rnorm(n = 3000,mean = 0,sd = 1),
  two = rnorm(n = 3000,mean = 0,sd = 1))
dt[, diff := one -two]
dt[, diff_cat := ifelse(one > 0 & two>0 & abs(diff)>1, "type_1",
                        ifelse(one<0 & two < 0 & abs(diff)>1, "type_2",
                               ifelse(two>0 & one<0 & abs(diff)>1, "type_3",
                                      ifelse(two<0 & one>0 & abs(diff)>1, "type_4", "other"))))]

# make plot
ggplot(dt, aes(x=one,y=two,color=diff_cat))+
  geom_point()

如果我只绘制我想要标记的点的子集,那么ggrepel能够相对于其他点和标签以非重叠的方式放置所有标签.

ggplot(dt[abs(diff)>2 & (!diff_cat %in% c("type_3","type_4","other"))], 
  aes(x=one,y=two,color=diff_cat))+
  geom_point()+
  geom_text_repel(data = dt[abs(diff)>2 & (!diff_cat %in% c("type_3","type_4","other"))], 
                  aes(x=one,y=two,label=name))

但是,当我想同时绘制这个数据子集和原始数据时,我得到了带标签的重叠点:

# now add labels to a subset of points on the plot
ggplot(dt, aes(x=one,y=two,color=diff_cat))+
  geom_point()+
  geom_text_repel(data = dt[abs(diff)>2 & (!diff_cat %in% c("type_3","type_4","other"))], 
                  aes(x=one,y=two,label=name))

如何才能使点子集的标签与原始数据中的点重叠？

Answer 1

您可以尝试以下方法:

1. ""为原始数据中的所有其他点分配一个空白标签(),以便geom_text_repel在彼此排斥标签时将其考虑在内;
2. 将box.padding参数从默认值0.25增加到更大的值,以增加标签之间的距离;
3. 增加x和y轴限制,使标签在四个侧面有更多的空间排斥.

示例代码(带box.padding = 1):

ggplot(dt, 
       aes(x = one, y = two, color = diff_cat)) +
  geom_point() +
  geom_text_repel(data = . %>% 
                    mutate(label = ifelse(diff_cat %in% c("type_1", "type_2") & abs(diff) > 2,
                                          name, "")),
                  aes(label = label), 
                  box.padding = 1,
                  show.legend = FALSE) + #this removes the 'a' from the legend
  coord_cartesian(xlim = c(-5, 5), ylim = c(-5, 5)) +
  theme_bw()

这是另一种尝试,包括box.padding = 2:

(注意:我正在使用ggrepel 0.8.0.我不确定早期软件包版本是否存在所有功能.)