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rggplot2plotaes

Plotting both individuals and average values in ggplot2: error "Error: `mapping` must be created by `aes()`"

I am trying to plot BOTH the individuals and averages on the same ggplot. I need to have color be the same between the individuals and averages. Aes seems to be the source of my problem, I have many more observations > 3000 and it will be important to see where averages and individuals lie in the plot space. I have tried separating everything into data.frames to combat the issue of using "$" in the aes function. I think the problem arises when I use "color" or "label" in the aes function. Maybe, ggplot does not like that the number of species' names are not the same?

# Libraries needed for example
library(dplyr)
library(ggplot2)

# Individuals PC1 and PC2 values
pc1 <- c(1,2,3,4,5,6,7,8,9,10)
pc2 <- c(4,5,6,7,8,9,10,11,12,13)
species <- c("D.a", "D.a", "D.b","D.b","D.c","D.c","D.d","D.d", "D.e", 
"D.e")

# Individual data frame
P1 <- cbind.data.frame(species,pc1,pc2)

# Averages of individuals
P2 <- P1 %>% group_by(species) %>%  summarise(pc1 = mean(pc1), pc2 = 
mean(pc2))

# GGplot
ggplot(P1, aes(x= pc1, y= pc2, color= species)) + geom_point(alpha= 0.2) 
+ geom_point(P2)

I expect to see the average values with the same color as their respective individual's color. This will hopefully evolve into allowing the same expectation with labels.

Solution

  • Be explicit about the data source and the aes mappings and it should work:

    ggplot(P1) + 
    geom_point(alpha = 0.2, aes(x = pc1, y = pc2, color = species)) +
    geom_point(data = P2, aes(x = pc1, y = pc2, color = species))

    output