ggplot2 missing facet wrap label on graph-CodePudding

I am using the following code to plot three sets of data and am also rearranging labels to a preferred order and making sure the 2 in R^2 is an exponent. As you can see the third panel of the facet wrap is empty. It should contain R2 (with 2 as exponent). I can't find the error that is leading to this in my code.

library(readxl)
library(ggplot2)
library(tidyr)

error3 <- read_excel('data/ggplot_error3.xlsx')
error3 <- transform(
  error3,
  Metric =as.factor(Metric),
  Model =as.factor(Model),
  Name =as.factor(Name),
  Buffer=as.factor(Buffer)
)

levels(error3$Metric)

#Set facet wrap labels
my_labeller <- as_labeller(c( MAE = 'MAE', RMSE = 'RMSE', `R^2` = 'R^2'), default = label_parsed)

# Line plot with multiple groups
ggplot(data=error3, aes(x=Buffer, y=Value, group=Model))    
  theme_bw()  
  geom_line(aes(color=Model))  
  geom_point(aes(color=Model))  
  labs(y = "Value", x = 'Buffer Radius (m)')  
  facet_wrap(~ Metric, nrow = 1, scales = "free_y", 
             labeller=my_labeller)

# Reorder line plot so R2 comes last
library(tidyverse)
library(dplyr)

error3 %>% mutate(across(Metric, factor, levels=c('MAE','RMSE','R2'))) %>%
  ggplot(aes(x=Buffer, y=Value, group=Model)) 
  geom_line(aes(color=Model))  
  geom_point(aes(color=Model))  
  theme_bw()  
  labs(y = "Value", x = 'Buffer radius (m)')  
  facet_wrap(~ Metric, nrow = 3, scales = "free_y", labeller=my_labeller)

#default level order
levels(error3$Model)

#change the order of labels
error3$Model <- factor(error3$Model, levels = c("RandomForest", "xgboost", "CART"))

#add superscript for R^2
error3 %>% mutate(across(Metric, factor, levels=c("MAE" , "RMSE", "R2"), labels = c('MAE', 'RMSE', 'R2'))) %>%
  ggplot(aes(x=Buffer, y=Value, group=Model)) 
  geom_line(aes(color=Model))  
  geom_point(aes(color=Model))  
  theme_bw()  
  labs(y = "Value", x = 'Buffer radius (m)')  
  facet_grid(~ Metric, labeller=my_labeller)  
  labs(color='Model name')

Code Sample:

error3 <-
  structure(
    list(
      Buffer = structure(
        c(
          1L,
          2L,
          3L,
          1L,
          2L,
          3L,
          1L,
          2L,
          3L,
          1L,
          2L,
          3L,
          1L,
          2L,
          3L,
          1L,
          2L,
          3L,
          1L,
          2L,
          3L,
          1L,
          2L,
          3L,
          1L,
          2L,
          3L
        ),
        .Label = c("500", "1000", "1500"),
        class = "factor"
      ),
      Area_km2 = c(
        0.7854,
        3.1416,
        7.0686,
        0.7854,
        3.1416,
        7.0686,
        0.7854,
        3.1416,
        7.0686,
        0.7854,
        3.1416,
        7.0686,
        0.7854,
        3.1416,
        7.0686,
        0.7854,
        3.1416,
        7.0686,
        0.7854,
        3.1416,
        7.0686,
        0.7854,
        3.1416,
        7.0686,
        0.7854,
        3.1416,
        7.0686
      ),
      Value = c(
        0.626344682,
        0.57916154,
        0.684365417,
        0.531505389,
        0.49978974,
        0.507811538,
        0.5155205,
        0.4966027,
        0.4992761,
        0.823620002,
        0.80962234,
        0.892280991,
        0.710242935,
        0.69967351,
        0.699732972,
        0.7211219,
        0.7104436,
        0.7156231,
        0.197019417,
        0.25163664,
        0.09162464,
        0.394737118,
        0.43074958,
        0.409713623,
        0.3719265,
        0.411827,
        0.3833796
      ),
      Metric = structure(
        c(
          1L,
          1L,
          1L,
          1L,
          1L,
          1L,
          1L,
          1L,
          1L,
          3L,
          3L,
          3L,
          3L,
          3L,
          3L,
          3L,
          3L,
          3L,
          2L,
          2L,
          2L,
          2L,
          2L,
          2L,
          2L,
          2L,
          2L
        ),
        .Label = c("MAE", "R2", "RMSE"),
        class = "factor"
      ),
      Model = structure(
        c(
          1L,
          1L,
          1L,
          2L,
          2L,
          2L,
          3L,
          3L,
          3L,
          1L,
          1L,
          1L,
          2L,
          2L,
          2L,
          3L,
          3L,
          3L,
          1L,
          1L,
          1L,
          2L,
          2L,
          2L,
          3L,
          3L,
          3L
        ),
        .Label = c("CART", "RandomForest", "xgboost"),
        class = "factor"
      ),
      Name = structure(
        c(
          1L,
          1L,
          1L,
          2L,
          2L,
          2L,
          3L,
          3L,
          3L,
          7L,
          7L,
          7L,
          8L,
          8L,
          8L,
          9L,
          9L,
          9L,
          4L,
          4L,
          4L,
          5L,
          5L,
          5L,
          6L,
          6L,
          6L
        ),
        .Label = c(
          "MAE_CART",
          "MAE_rf",
          "MAE_xgboost",
          "R2_CART",
          "R2_rf",
          "R2_xgboost",
          "RMSE_CART",
          "RMSE_rf",
          "RMSE_xgboost"
        ),
        class = "factor"
      )
    ),
    class = "data.frame",
    row.names = c(NA,-27L)
  )

enter code here

CodePudding user response：

As I already mentioned in my comment the R^2 is coded as R2 in your Metric column. Hence you could fix your issue using as_labeller(c(..., R2 = "R^2")):

library(ggplot2)
library(tidyr)
library(dplyr)

my_labeller <- as_labeller(c(MAE = "MAE", RMSE = "RMSE", R2 = "R^2"), default = label_parsed)

error3 <- error3 %>% mutate(across(Metric, factor, levels = c("MAE", "RMSE", "R2")))

ggplot(data = error3, aes(x = Buffer, y = Value, group = Model))  
  theme_bw()  
  geom_line(aes(color = Model))  
  geom_point(aes(color = Model))  
  labs(y = "Value", x = "Buffer Radius (m)")  
  facet_wrap(~Metric,
    nrow = 1, scales = "free_y",
    labeller = my_labeller
  )