R ggplot2 change geom_bar to a single color-CodePudding

Based on the code and data below, how can I change the bar colors to a single color #0277BD?

I tried scale_fill_manual(values=c("#0277BD")), but it doesn't work.

Error in `f()`:
! Insufficient values in manual scale. 24 needed but only 1 provided.

I also tried scale_fill_brewer(palette="Blues"), but this doesn't work either.

Warning message:
In RColorBrewer::brewer.pal(n, pal) :
  n too large, allowed maximum for palette Blues is 9
Returning the palette you asked for with that many colors

Data:

df = structure(list(CITYNAME = c("a", "b", "c", 
    "d", "e", "f", "g", 
    "h", "i", "j", "k", 
    "l", "m", "n", "p", "q", 
    "r", "s", "t", "u", 
    "w", "x", "y", "z"), AvgTMin = c(20.28, 
20.38, 20.08, 20.35, 20.38, 20.76, 21, 21.21, 20.45, 20.21, 21.18, 
20.29, 20.61, 20.44, 20.95, 19.75, 20.58, 20.32, 21.05, 20.28, 
20.09, 20.15, 20.73, 20.12)), row.names = c(NA, 
    -24L), class = c("tbl_df", "tbl", "data.frame"))

Code:

# Plot in Fahrenheit

    df %>% mutate(AvgTMin = AvgTMin * (1.8)   32) %>% # Convert from C to F
          ggplot(aes(x = reorder(CITYNAME,AvgTMin), y = AvgTMin, fill = CITYNAME))  
          geom_bar(stat="identity")  
          coord_cartesian(ylim = c(60,70.3))  
          theme(axis.text = element_text(size = 14))  
          geom_text(aes(label=sprintf("%0.2f", AvgTMin)), vjust=-0.2, size = 4)  
          labs(x = NULL, y = "Avg. Min. Temperature \u00B0F")   
          theme(axis.text.x = element_text(angle = 90),  legend.position = 'none')  
          ggtitle("1980-2021 Temperature Trend By City")

CodePudding user response：

You can specify the single color in the geom_bar call:

  geom_bar(stat="identity", fill = "0277BD")

In your code you can also delete the fill aesthetic in the ggplot call unless you need it for other layers.

CodePudding user response：

Another option if you did want to leave the fill parameter alone, then you could still use scale_fill_manual, but you would need to replicate color for all of the unique values.

library(tidyverse)

df %>%
  mutate(AvgTMin = AvgTMin * (1.8)   32) %>% # Convert from C to F
  ggplot(aes(
    x = reorder(CITYNAME, AvgTMin),
    y = AvgTMin,
    fill = CITYNAME
  ))  
  geom_bar(stat = "identity")  
  coord_cartesian(ylim = c(60, 70.3))  
  theme(axis.text = element_text(size = 14))  
  geom_text(aes(label = sprintf("%0.2f", AvgTMin)), vjust = -0.2, size = 4)  
  labs(x = NULL, y = "Avg. Min. Temperature \u00B0F")  
  theme(axis.text.x = element_text(angle = 90),
        legend.position = 'none')  
  ggtitle("1980-2021 Temperature Trend By City")  
  scale_fill_manual(values = rep_len("#0277BD", length(unique(df$CITYNAME))))

Output