How to combine legends in ggplot2

Question

I'm a beginner learner with R. I've been attempting to combine legends for so long and just can't seem to do it.

Data works fine and is accurate and plotted properly. Except colour and shape aren't combined in one legend but in separate legends.

Here's my code:


ggp1 <- ggplot(data, aes(x = Year)) +
  geom_point(aes(y = Temperature, colour = "Africa", shape = "Africa")) +  
  geom_point(aes(y = y2, colour = "Asia", shape = "Asia")) +
  geom_point(aes(y = y3, colour = "Europe", shape = "Europe")) + 
  geom_point(aes(y = y4, colour = "Australia", shape = "Australia"))

Edit: Here's the data:

data <- data.frame(Year = df1$Year,
               Temperature = df1$Temperature.Africa,
               y2 = df1$Temperature.Asia,
               y3 = df1$Temperature.Europe,
               y4 = df1$Temperature.Australia)

This is the output of the code

Please help before I go crazy.

Your data will need to be reshaped. If you have a sample of data (or simulated numbers) to show the structure of the data we can help work out a solution. — Andy Baxter, Nov 18 '22 at 13:30

score 1 · Answer 1 · answered Nov 18 '22 at 14:10

You could achieve your desired result by assigning the same name to the color and shape legends or by removing both as I do in my code below using labs.

Using a minimal reproducible example based on the gapminder dataset:

library(gapminder)
library(tidyverse)

# Create example data
data <- gapminder |> 
  select(Year = year, continent, value = lifeExp) |> 
  group_by(Year, continent) |> 
  summarise(value = mean(value), .groups = "drop") |> 
  pivot_wider(names_from = continent, values_from = value) |> 
  select(Year, Temperature = 2, y2 = 3, y3 = 4, y4 = 5)
  
ggplot(data, aes(x = Year)) +
  geom_point(aes(y = Temperature, colour = "Africa", shape = "Africa")) +  
  geom_point(aes(y = y2, colour = "Asia", shape = "Asia")) +
  geom_point(aes(y = y3, colour = "Europe", shape = "Europe")) + 
  geom_point(aes(y = y4, colour = "Australia", shape = "Australia")) +
  labs(color = NULL, shape = NULL)

How to combine legends in ggplot2

1 Answers1