How to plot two variables of the same abscissa in the same line?-CodePudding

I want to plot two variables of the same abscissa in a same line. If it is the same abscissa, the two variables will be displayed on the same abscissa. But I want to keep them separate without affecting the coherence of the abscissa.

Here is the original data:

df<-structure(list(Bloc = c(7, 7, 8, 8, 5, 5, 7, 7, 8, 8, 5, 5, 7, 
                            7, 8, 8, 5, 5, 7, 7, 8, 8, 5, 5), Pos_heliaphen = c("W16", "W17", 
                                                                                "W36", "W37", "X02", "X03", "W16", "W17", "W36", "W37", "X02", 
                                                                                "X03", "W16", "W17", "W36", "W37", "X02", "X03", "W16", "W17", 
                                                                                "W36", "W37", "X02", "X03"), traitement = c("WS", "WW", "WW", 
                                                                                                                            "WS", "WS", "WW", "WS", "WW", "WW", "WS", "WS", "WW", "WS", "WW", 
                                                                                                                            "WW", "WS", "WS", "WW", "WS", "WW", "WW", "WS", "WS", "WW"), 
                   Variete = c("Blancas", "Blancas", "Blancas", "Blancas", "Blancas", 
                               "Blancas", "Blancas", "Blancas", "Blancas", "Blancas", "Blancas", 
                               "Blancas", "Blancas", "Blancas", "Blancas", "Blancas", "Blancas", 
                               "Blancas", "Blancas", "Blancas", "Blancas", "Blancas", "Blancas", 
                               "Blancas"), Date_obs = c("D1_27/05/2021", "D1_27/05/2021", 
                                                        "D1_27/05/2021", "D1_27/05/2021", "D1_27/05/2021", "D1_27/05/2021", 
                                                        "D2_28/05/2021", "D2_28/05/2021", "D2_28/05/2021", "D2_28/05/2021", 
                                                        "D2_28/05/2021", "D2_28/05/2021", "D3_29/05/2021", "D3_29/05/2021", 
                                                        "D3_29/05/2021", "D3_29/05/2021", "D3_29/05/2021", "D3_29/05/2021", 
                                                        "D4_30/05/2021", "D4_30/05/2021", "D4_30/05/2021", "D4_30/05/2021", 
                                                        "D4_30/05/2021", "D4_30/05/2021"), P_av_arros = c(0.51, 0.53, 
                                                                                                          0.55, 0.57, 0.59, 0.61, 0.63, 0.65, 0.67, 0.69, 0.71, 0.73, 
                                                                                                          0.75, 0.77, 0.79, 0.81, 0.83, 0.85, 0.87, 0.89, 0.91, 0.93, 
                                                                                                          0.95, 0.97), FTSW_apres_arros = c(0.91, 0.92, 0.93, 0.94, 
                                                                                                                                            0.95, 0.96, 0.97, 0.98, 0.99, 1, 1.01, 1.02, 1.03, 1.04, 
                                                                                                                                            1.05, 1.06, 1.07, 1.08, 1.09, 1.1, 1.11, 1.12, 1.13, 1.14
                                                                                                          )), class = c("tbl_df", "tbl", "data.frame"), row.names = c(NA, 
                                                                                                                                                                      -24L))

I gained this code from previous questions. But this is when the abscissa is in the format of the date. Now I'm wondering what should I do if the abscissa is not a date, just a non-consecutive value?

library(ggplot2)
library(dplyr)

labels <- df %>% 
  select(Bloc, Pos_heliaphen) %>% 
  distinct(Bloc, Pos_heliaphen) %>% 
  group_by(Bloc) %>% 
  summarise(Pos_heliaphen = paste(Pos_heliaphen, collapse = "-")) %>% 
  tibble::deframe()

df %>%
  mutate(Date_obs = as.POSIXct(lubridate::dmy(Date_obs))) %>%
  tidyr::pivot_longer(6:7) %>%
  mutate(Date_obs = if_else(name == "FTSW_apres_arros", 
                            Date_obs   43200, Date_obs)) %>%
  ggplot(aes(Date_obs, value, colour = factor(Bloc), shape = traitement, 
             linetype = traitement, group = interaction(Bloc, traitement)))  
  geom_point()  
  geom_line()  
  scale_color_discrete(labels = labels, guide = guide_legend(order = 1))  
  scale_x_datetime(date_labels = "%d/%m/%Y", date_breaks = "day")  
  labs(y = expression(paste("FTSW")))  
  theme(legend.position = "bottom", 
        axis.text.x = element_text(angle = 90, hjust = 1))

I hope I can get this graph:

Thank you in advance!

CodePudding user response：

In this particular case, it is going to be easiest to stick to dealing with "proper" dates and just recreating the labels for the x axis.

df %>%
  tidyr::separate(Date_obs, c("Obs", "Date_obs"), sep = "_") %>%
  mutate(Date_obs = as.POSIXct(lubridate::dmy(Date_obs))) %>%
  tidyr::pivot_longer(7:8) %>%
  mutate(Date_obs = if_else(name == "FTSW_apres_arros", 
                            Date_obs   43200, Date_obs)) %>%
  ggplot(aes(Date_obs, value, colour = factor(Bloc), shape = traitement, 
             linetype = traitement, group = interaction(Bloc, traitement)))  
  geom_point()  
  geom_line()  
  scale_color_discrete(labels = labels, guide = guide_legend(order = 1))  
  scale_x_datetime(labels = ~ paste0("D", seq_along(.x) - 1, "_", 
                                     strftime(.x, "%d/%m/%Y")),
                   date_breaks = "day")  
  labs(y = expression(paste("FTSW")))  
  theme(legend.position = "bottom", 
        axis.text.x = element_text(angle = 90, hjust = 1))