在 ggplot 图例中控制颜色、填充和线型

Question

I have data of two model results with variation presented as shaded quantiles and for each model a reference benchmark without variation. See the example data here:

# create data
y <- 1+0.1*c(0:29)
r1 <- runif(30,0.8,1.2)
mydata0 <- data.frame(model = "model1",scenario="a_sc1", year = c(2022:2051), q9 = y+2*r1,
                     q7=y+r1, q5=y+r1-1,q3=y-r1,q1=y-2*r1,bench= r1)

mydata1 <- mydata0
mydata1[,4:9] <- r1+mydata1[,4:9]
mydata1$model <- "model2"

mydata <- rbind(mydata0, mydata1)

I plot is in the following way, which is what I need, but the legend is missing the benchmark with line type.

library(ggplot2)
col2 <- c("darkred","steelblue")
col2f <- c("magenta","green")

ggplot(data=mydata, aes(x=year, group=model)) +
  geom_ribbon(aes(ymin=q1 , ymax=q9,fill=model),  linetype=0, alpha=0.2) +
  geom_ribbon(aes(ymin=q3 , ymax=q7,fill=model),  linetype=0, alpha=0.2) +
  geom_line(aes(x=year, y=q5 ,color=model), linetype=1, size=1.3)+
  geom_line(aes(x=year, y=bench ,color=model), linetype=2, size=1.3)+
  scale_color_manual(values = col2) +
  scale_fill_manual(values = col2f)+
  scale_linetype_manual(values = c(1,2)) +
  labs( y = "var [mg/l]", x="") +
  theme_light() +
  theme(text = element_text(size = 18),axis.text=element_text(colour="black",size=20),legend.text=element_text(size=22))

< >

I arrange the data in a long format and plot as follows:

# second trail: long data
mydata2 <- rbind(mydata[,-9], data.frame(model=mydata$model,scenario="bench",year=mydata$year,q9=NA,q7=NA,q5=mydata$bench,q3=NA,q1=NA))
  
  ggplot(data=mydata2, aes(x=year)) +
    geom_ribbon(aes(ymin=q1 , ymax=q9,fill=model),  linetype=0, alpha=0.2, na.rm = TRUE) +
    geom_ribbon(aes(ymin=q3 , ymax=q7,fill=model),  linetype=0, alpha=0.2, na.rm = TRUE) +
    geom_line(aes(x=year, y=q5 ,color=model, linetype=scenario), size=1.3)+
    scale_color_manual(values = col2) +
    scale_fill_manual(values = col2f)+
    labs( y = "var [mg/l]", x="") +
    theme_light() +
    theme(text = element_text(size = 18),axis.text=element_text(colour="black",size=20),legend.text=element_text(size=22))

< > Now I do have the legend of the benchmark - the l.netype is correct, but the coloring is missing. I did not succeed adding it. Appreciate any ideas.

***** EDIT ******

I add here a graphicly edited image of how I want it to appear. Seems to me that my first approach would be better (not in long format) but how do I add the legend?

Answer 1

If you want both the l.netype and the color of your lines to be displayed in the legend then one option would be to map the interaction of model and scenario on the color and l.netype aesthetics, which however requires to set a manual palettes taking the interaction into account:

library(ggplot2)

pal_color <- rep(col2, each = 2)
pal_lty <- rep(c("solid", "dashed"), 2)

names(pal_color) <- names(pal_lty) <- c("model1.a_sc1", "model1.bench", "model2.a_sc1", "model2.bench")

ggplot(data = mydata2, aes(x = year)) +
  geom_ribbon(aes(ymin = q1, ymax = q9, fill = model), linetype = 0, alpha = 0.2, na.rm = TRUE) +
  geom_ribbon(aes(ymin = q3, ymax = q7, fill = model), linetype = 0, alpha = 0.2, na.rm = TRUE) +
  geom_line(aes(
    x = year, y = q5,
    color = paste(model, scenario, sep = "."),
    linetype = paste(model, scenario, sep = ".")
  ), size = 1.3) +
  scale_color_manual(values = pal_color) +
  scale_linetype_manual(values = pal_lty) +
  scale_fill_manual(values = col2f) +
  labs(y = "var [mg/l]", x = "") +
  theme_light() +
  theme(
    text = element_text(size = 18),
    axis.text = element_text(colour = "black", size = 20),
    legend.text = element_text(size = 22)
  )

UPDATE Based on the edit containing an image of your desired result we have to do some adjustments, basically a mix of your original and my approach. First, stick with color=model so that we get a color/fill legend displaying both the ribbons and the solid lines. To fix the l.netype legend set the breaks (and labels) so that only the benchmark lines are displayed in the legend. Additionally we have to do a hack via the override.aes argument of guide_legend to the colors to l.netype legend:

Note: I also fixed the livetypes. I had chosen "dashed" but after a closer look IMHO it should be 22 .

library(ggplot2)

pal_lty <- rep(c("solid", "22"), 2)

names(pal_lty) <- c("model1.a_sc1", "model1.bench", "model2.a_sc1", "model2.bench")

ggplot(data = mydata2, aes(x = year)) +
  geom_ribbon(aes(ymin = q1, ymax = q9, fill = model), linetype = 0, alpha = 0.2, na.rm = TRUE) +
  geom_ribbon(aes(ymin = q3, ymax = q7, fill = model), linetype = 0, alpha = 0.2, na.rm = TRUE) +
  geom_line(aes(
    x = year, y = q5,
    color = model,
    linetype = paste(model, scenario, sep = ".")
  ), size = 1.3) +
  scale_color_manual(values = col2) +
  scale_linetype_manual(
    values = pal_lty,
    breaks = c("model1.bench", "model2.bench"),
    labels = c("Bench_model1", "Bench_model2"),
    guide = guide_legend(override.aes = list(color = col2))
  ) +
  scale_fill_manual(values = col2f) +
  labs(y = "var [mg/l]", x = "", linetype = "Bench") +
  theme_light() +
  theme(
    text = element_text(size = 18),
    axis.text = element_text(colour = "black", size = 20),
    legend.text = element_text(size = 22)
  )