R 在散点图中使用geom_point放置线图例

两种方式:

1. 你有geom_point twice，但我相信第二个是你想要的，因为第一个没有aes(.).(我认为这意味着你是双重标绘点...虽然看不见，但仍在发生).如果注释掉第一个geom_point()，并从第二个中删除show.legend=TRUE，它就可以工作.

   ggplot(df, aes(x = project, y = sat)) + 
     # geom_point() +                                                    # REMOVE
     facet_grid(.~cohort) +
     scale_x_continuous(limits = c(1, 3), breaks = seq(1, 3, by = 0.5)) +
     geom_smooth(method = "lm", se = F) +
     labs(x = "Total Project score", y = "Total SAT") + 
     ggpubr::stat_cor(method = "pearson", size = 2.6, digits= 2) +
     geom_vline(
       aes(xintercept = x, colour = group, linetype = group),
       threshold
     )+ 
     scale_linetype_manual(
       name = "Project Performance",
       values = c(pass = "solid", "scholarship eligible" = "dashed")
     ) +
     scale_color_manual(
       name = "Project Performance",
       values = c(pass = "red", "scholarship eligible" = "darkgreen")
     ) +
     ggnewscale::new_scale_color() +
     geom_point(aes(colour = pass_sat)) +                                # UPDATE
     scale_color_manual(name = "SAT Performance", values = c("Met Threshold" = "purple", "Did Not Meet Threshold" = "black")) +
     labs(title= "Total SAT by Overall Project Score, by Year")
   

   

2. 在第一个色标生效时，在调用new_scale_color()之前加上guides(..)和override.aes.(如果您按新比例执行after，则第二个图例中的点将被删除，而不是您所要求的.)

   ggplot(df, aes(x = project, y = sat)) + 
     geom_point() +
     facet_grid(.~cohort) +
     scale_x_continuous(limits = c(1, 3), breaks = seq(1, 3, by = 0.5)) +
     geom_smooth(method = "lm", se = F) +
     labs(x = "Total Project score", y = "Total SAT") + 
     ggpubr::stat_cor(method = "pearson", size = 2.6, digits= 2) +
     geom_vline(
       aes(xintercept = x, colour = group, linetype = group),
       threshold
     )+ 
     scale_linetype_manual(
       name = "Project Performance",
       values = c(pass = "solid", "scholarship eligible" = "dashed")
     ) +
     scale_color_manual(
       name = "Project Performance",
       values = c(pass = "red", "scholarship eligible" = "darkgreen")
     ) +
     guides(color = guide_legend(override.aes = list(shape = NA))) +     # NEW
     new_scale_color() +
     geom_point(aes(colour = pass_sat),
                show.legend = TRUE) +
     scale_color_manual(name = "SAT Performance", values = c("Met Threshold" = "purple", "Did Not Meet Threshold" = "black")) +
     labs(title= "Total SAT by Overall Project Score, by Year")