如何 label 僅 ggplot2 中的某些點

Question

我有一個 dataframe global三列Year ， MTCO2和Scenario 。 我已經創建了一個散點圖，看起來我想要它，但我正在努力解決如何在 plot 上僅幾個點來最好地優化 label。

到目前為止，這是我的代碼：

plot1 <- global %>% 
ggplot(aes(Year, MTCO2, group = Scenario, colour = Scenario)) + 
  geom_line(size = 1) +
  geom_point(size = 2) +
  scale_x_continuous(name = "Year", breaks = c(1990, 2000, 2006, 2020, 2030, 2040, 2050)) +
  theme_bw() +
  labs(title = "Global CO2 Emissions Projections with and without Constraints")
plot1a <- plot1 + geom_text(data = subset(global, Year == 2006 | Year == 2030 | Year == 2050 ),
                                     aes(Year, MTCO2, label = MTCO2))

這就是 plot 的樣子

我的目標是要使文本是黑色的，從一條線連接到該點的角度，有一個label在2006年，一個ZD304BA20E96DBA20E96D87411588EBAAC8YEABAC8550E11 for 2030 for 2030 for 2030 and888888888888888888888888888888888888888888808.僅限 Global_Constraint 行）。 我還希望能夠在點值之后寫更多（即 8261，基准年值）。 圖例還在點上顯示了字母“a”，我也想去掉它。

這是數據：

dput(global)
structure(list(Year = c(1990, 2005, 2006, 2010, 2015, 2020, 2025, 
2030, 2035, 2040, 2045, 2050, 1990, 2005, 2006, 2010, 2015, 2020, 
2025, 2030, 2035, 2040, 2045, 2050), MTCO2 = c(6045, 8039, 8261, 
9149, 9646, 10453, 7889, 6937, 5467, 4400, 2589, 2432, 6045, 
8039, 8261, 9149, 9646, 10528, 11488, 12368, 13092, 13708, 14305, 
14754), Scenario = c("Global_Constraint", "Global_Constraint", 
"Global_Constraint", "Global_Constraint", "Global_Constraint", 
"Global_Constraint", "Global_Constraint", "Global_Constraint", 
"Global_Constraint", "Global_Constraint", "Global_Constraint", 
"Global_Constraint", "Global_Reference", "Global_Reference", 
"Global_Reference", "Global_Reference", "Global_Reference", "Global_Reference", 
"Global_Reference", "Global_Reference", "Global_Reference", "Global_Reference", 
"Global_Reference", "Global_Reference")), class = c("spec_tbl_df", 
"tbl_df", "tbl", "data.frame"), row.names = c(NA, -24L), spec = structure(list(
    cols = list(Year = structure(list(), class = c("collector_double", 
    "collector")), MTCO2 = structure(list(), class = c("collector_double", 
    "collector")), Scenario = structure(list(), class = c("collector_character", 
    "collector"))), default = structure(list(), class = c("collector_guess", 
    "collector")), skip = 1), class = "col_spec"))

Answer 1

我想有幾種方法可以解決它。 只需對您的代碼進行最少的更改，我就嘗試過：

library(ggplot2)
plot1 <- global %>% 
  ggplot(aes(Year, MTCO2, group = Scenario, colour = Scenario)) + 
  geom_line(size = 1) +
  geom_point(size = 2) +
  scale_x_continuous(name = "Year", breaks = c(1990, 2000, 2006, 2020, 2030, 2040, 2050)) +
  theme_bw() +
  labs(title = "Global CO2 Emissions Projections with and without Constraints")
plot1a <- plot1 + geom_text(data = subset(global, Year == 2006 | Year == 2030 | Year == 2050 ),
                            aes(Year, MTCO2, label = MTCO2), 
                            color = "black", nudge_x = -6)

Answer 2

我認為最簡單的方法是創建 label，然后設計 plot：

#Format data
global %>% mutate(label=ifelse(Year %in% c(2006,2030,2050),MTCO2,NA)) -> global
#Plot
ggplot(global,aes(x=Year, y=MTCO2,label=label)) + 
  geom_line(size = 1,aes(color = Scenario)) +
  geom_point(size = 2,aes(color = Scenario)) +
  geom_text(vjust=-1)+
  scale_x_continuous(name = "Year", breaks = c(1990, 2000, 2006, 2020, 2030, 2040, 2050)) +
  theme_bw() +
  labs(title = "Global CO2 Emissions Projections with and without Constraints")