Creating a line chart with a factor variable and a continuous variable in ggplot r

Question

I have the following data:

cefr_hours <- data.frame(cefr = as.factor(c("A2", "B1", "B2", "C1", "C2")),
                         hours = c(200, 400, 600, 800, 1200))

And I have created the following plot:

  ggplot(cefr_hours, aes(x = cefr, y = hours)) +
      geom_point() +
      geom_line() +
      theme_minimal() +
      labs(title = "Hours of Guided Learning Per Level", subtitle = "Source: Cambridge English Assessment") +
      xlab("CEFR Level") +
      ylab("Number of Hours")

What I want to do is draw an arrow through each of the points and then shade the area under the line and between the points similar to this meaning the colors between each of the levels would be different.

Thank you in advance for your assistance.

Yes. I have edited my points to make this idea clear. Thank you. — Evan
– Evan, Commented Oct 29, 2018 at 13:09

Jordo82 · Accepted Answer · 2018-10-29 13:50:01Z

1

This is pretty hacky, but it works. I had to play with the data a bit to create "groups" of the data from A2 to B1, then B1 to B2 and so on. I'm sure there's a better way of doing this.

library(tidyverse)

cefr_hours <- data_frame(cefr = as.factor(c("A2", "B1", "B2", "C1", "C2")),
                         hours = c(200, 400, 600, 800, 1200))

#duplicate the data and create an indicator for group
cefr_hours <- cefr_hours %>% 
  bind_rows(cefr_hours) %>% 
  arrange(cefr) %>% 
  #create a group for A2 to B1, then B1 to B2, etc.
  mutate(group = ceiling((row_number() - 1) / 2)) %>% 
  #exclude the first and last points
  filter(group != min(group), group != max(group)) %>% 
  #convert from numeric to character
  mutate(group = letters[group])

ggplot(cefr_hours, aes(x= cefr, y=hours, group = group, fill = group)) +
  geom_ribbon(aes(ymin = 0, ymax = hours))+
  geom_point() +
  geom_line(arrow = arrow(angle = 15, ends = "last", type = "closed")) +
  theme_minimal() +
  labs(title = "Hours of Guided Learning Per Level", 
       subtitle = "Source: Cambridge English Assessment",
       x = "CEFR Level",
       y = "Number of Hours") +
  scale_fill_brewer(palette = "Dark2") + 
  theme(legend.position = "none")

edited Oct 29, 2018 at 13:50

answered Oct 29, 2018 at 13:08

Jordo82

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1 Comment

Jordo82 Over a year ago

Edited to have multiple colors

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