带有 geom_line 和 geom_ribbon 和 geom_point 的图例

Question

I've been searching the answer for two days and still can't find how to do this. The closest cases I found here and here . But the former has no points on the plots and the latter has no answer. Without much ado, how to add points to my legend? This is my data:

Year <- c(2003:2020)
TheData <- c(72.6, 72.7, 72.6, 72.5, 72.4, 72.1, 71.8, 71.7, 71.8, 72.3, 72.7,
              72.9, 73.1, 73.3, 73.8, 74.7, 75.7, 77.1)
Lower <- c(72.33316, 72.05961, 71.8218, 71.62303, 71.46657, 71.35567, 71.29362,
           71.28368, 71.32915, 71.43331, 71.59947, 71.83096, 72.13113, 72.50333,
           72.95092, 73.47728, 74.08581, 74.77989)
Upper <- c(73.46626, 73.24078, 73.05676, 72.91817, 72.82899, 72.79323, 72.81489,
           72.89794, 73.04639, 73.26418, 73.55528, 73.92363, 74.37315, 74.90775,
           75.53132, 76.24776, 77.06094, 77.97473)
Model <- c(72.89971, 72.65020, 72.43928, 72.27060, 72.14778, 72.07445, 72.05425,
           72.09081, 72.18777, 72.34874, 72.57738, 72.87730, 73.25214, 73.70554,
           74.24112, 74.86252, 75.57337, 76.37731)
MyDF <- data.frame(Year, TheData, Lower, Upper, Model) 

This is my code:

library("ggplot2")
ggplot(MyDF, aes(x = Year, y = TheData)) +
    geom_point(aes(y = TheData), size = 2.5) +
    geom_line(aes(x = Year, y = Model, color = "Model", fill = "Model")) +
    geom_ribbon(aes(ymin = Lower, ymax = Upper, x = Year,
                    fill = "Confidence Interval"), alpha = 0.15) +
    scale_colour_manual(
        name = "", values = c("Confidence Interval" = "transparent",
                             "Model" = "black")) +
    scale_fill_manual(
        name = "",  values = c("Confidence Interval" = "grey12",
                               "Model" = "transparent")) +
    theme(legend.position = "bottom")

This is my plot.

Answer 1

If you want to get a legend you have to map on an aesthetic, eg you could map on the shape aes to get a legend for your points too:

library("ggplot2")

ggplot(MyDF, aes(x = Year, y = TheData)) +
  geom_point(aes(y = TheData, shape = "TheData"), size = 2.5) +
  geom_line(aes(x = Year, y = Model, color = "Model")) +
  geom_ribbon(aes(ymin = Lower, ymax = Upper, x = Year,
                  fill = "Confidence Interval"), alpha = 0.15) +
  scale_colour_manual(
    name = "", values = c("Confidence Interval" = "transparent",
                          "Model" = "black")) +
  scale_fill_manual(
    name = "",  values = c("Confidence Interval" = "grey12",
                           "Model" = "transparent")) +
  theme(legend.position = "bottom") +
  labs(shape = "")

Answer 2

If somebody is interested to move the legend to free space on the plot there is an obvious way to do so:

ggplot(MyDF, aes(x = Year, y = TheData)) +
geom_point(aes(y = TheData, shape = "TheData"), size = 2.5) +
geom_line(aes(x = Year, y = Model, color = "Model")) +
geom_ribbon(aes(ymin = Lower, ymax = Upper, x = Year,
                fill = "Confidence Interval"), alpha = 0.15) +
scale_colour_manual(
    name = "", values = c("Confidence Interval" = "transparent",
                          "Model" = "black")) +
scale_fill_manual(
    name = "",  values = c("Confidence Interval" = "grey12",
                           "Model" = "transparent")) +
theme(legend.position = "bottom") +
labs(shape = "") +
theme(legend.position = c(.4, .7))

But the legend appears stacked: Adding + guides(color = guide_legend(nrow = 1)) does not work:

My colleague have proposed to add legend.box = "horizontal" . This code works:

ggplot(MyDF, aes(x = Year, y = TheData)) +
geom_point(aes(y = TheData, shape = "TheData"), size = 2.5) +
geom_line(aes(x = Year, y = Model, color = "Model")) +
geom_ribbon(aes(ymin = Lower, ymax = Upper, x = Year,
                fill = "Confidence Interval"), alpha = 0.15) +
scale_colour_manual(
    name = "", values = c("Confidence Interval" = "transparent",
                          "Model" = "black")) +
scale_fill_manual(
    name = "",  values = c("Confidence Interval" = "grey12",
                           "Model" = "transparent")) +
theme(legend.position = "bottom") +
labs(shape = "") +
theme(legend.position = c(.4, .7), legend.box = "horizontal") +
guides(color = guide_legend(nrow = 1))

The plot looks like this:

Still, I wonder why the legend appears in different boxes and how to put it together?