在 ggplot 中注釋一條 geom_smooth 線

Question

給定以下虛擬數據集

df = structure(list(date = structure(c(19128, 19129, 19130, 19131, 
                                   19132, 19133, 19134, 19135, 19136, 19137, 19138, 19139, 19140, 
                                   19141, 19142, 19143, 19144), class = "Date"), av7 = c(108.55, 
                                                                                         108.875, 108.916666666667, 108.725, 108.92, 108.877777777778, 
                                                                                         108.841666666667, 108.70119047619, 108.525, 108.329761904762, 
                                                                                         108.115476190476, 107.94880952381, 107.877380952381, 107.652380952381, 
                                                                                         107.609523809524, 107.495238095238, 107.390476190476), ch7 = c(-0.15, 
                                                                                                                                                        -0.35, -0.59, -0.61, -0.97, -1, 0, 0.15, -0.35, -0.59, -0.61, -0.97, -1, 
                                                                                                                                                        -1.19, -1.09, -1.03, -0.94)), row.names = c(NA, -17L), class = c("tbl_df", 
                                                                                                                                                                                                                         "tbl", "data.frame"))

我想為av7變量繪制一條平滑的線，並用ch7變量的值對該線進行注釋。 我試過這段代碼：

ggplot(df, aes(x = date, y=av7, label = ch7))+
  geom_smooth(se=F)+
  geom_text(nudge_y = 0.2)

但是，正如您在下面看到的，label 的 position 不與平滑線對齊，因為它遵循原始點的 position：

我還嘗試使用stat = "smooth" witin geom_text如下：

ggplot(df, aes(x = date, y=av7, label = ch7))+
  geom_smooth(se=F)+
  geom_text(nudge_y = 0.2,
            stat = "smooth")

但我收到以下錯誤：

Error: geom_text requires the following missing aesthetics: label

任何幫助將非常感激。

Answer 1

一種方法是將 loess smooth 的值分配給原始數據框，然后將線和點分別分配給 plot：

df <- df %>% mutate(sm = predict(loess(av7~as.numeric(date), data=df)))

ggplot(df, aes(x = date, y=sm, label = ch7))+
  geom_line(color="blue") + geom_text(nudge_y=0.2)

Answer 2

如果 x 定位不是很重要，那么您也可以使用 geomtextpath package。遺憾的是，它目前每行只允許一個 label ，因此您只能折疊標簽並偽造它在整行上的分布。 只有當你想或多或少地平均分布在曲線上時，這才有效。

library(geomtextpath)
#> Loading required package: ggplot2
df = structure(list(date = structure(c(19128, 19129, 19130, 19131, 
                                       19132, 19133, 19134, 19135, 19136, 19137, 19138, 19139, 19140, 
                                       19141, 19142, 19143, 19144), class = "Date"), av7 = c(108.55, 
                                                                                             108.875, 108.916666666667, 108.725, 108.92, 108.877777777778, 
                                                                                             108.841666666667, 108.70119047619, 108.525, 108.329761904762, 
                                                                                             108.115476190476, 107.94880952381, 107.877380952381, 107.652380952381, 
                                                                                             107.609523809524, 107.495238095238, 107.390476190476), ch7 = c(-0.15, 
                                                                                                                                                            -0.35, -0.59, -0.61, -0.97, -1, 0, 0.15, -0.35, -0.59, -0.61, -0.97, -1, 
                                                                                                                                                            -1.19, -1.09, -1.03, -0.94)), row.names = c(NA, -17L), class = c("tbl_df", 
                                                                                                                                                                                                                             "tbl", "data.frame"))
ggplot(df, aes(x = date, y = av7)) +
  geom_textsmooth(aes(label = paste(ch7, collapse = "  ")))
#> `geom_smooth()` using method = 'loess' and formula 'y ~ x'

^{由reprex package (v2.0.1) 創建於 2022-06-01}