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ggplot2 geom_segment() in R: Draw Line Segments

The geom_segment() function in ggplot2 draws line segments between explicit start and end points, specified via x, y, xend, and yend aesthetics. Useful for arrows, lollipop charts, and custom annotations.

By Selva Prabhakaran  ·  Published May 12, 2026  ·  Last updated May 12, 2026
⚡ Quick Answer
ggplot(df, aes(x, y, xend = xend, yend = yend)) + geom_segment()
geom_segment(arrow = arrow())
ggplot(df, aes(x, y)) + geom_segment(aes(xend = x, yend = 0))  # lollipop
geom_curve(...)                          # curved version

Need explanation? Read on for examples and pitfalls.

📊 Is geom_segment() the right tool?
STARTstraight line between 2 specific pointsgeom_segment()curved connectiongeom_curve()arrow with textgeom_segment(arrow = ...) + annotatelollipop chartgeom_segment(aes(xend, yend = 0)) + geom_point()error barsgeom_errorbar()

What geom_segment() does in one sentence

geom_segment() draws straight line segments from (x, y) to (xend, yend) for each row of data. Each row produces ONE segment.

Syntax

geom_segment(mapping = NULL, data = NULL, arrow = NULL, lineend = "butt", ...). Requires aes(x, y, xend, yend).

Run live
Run live, no install needed. Every R block on this page runs in your browser. Click Run, edit the code, re-run instantly. No setup.
RLollipop chart
library(ggplot2) library(dplyr) library(tibble) mtcars |> tibble::rownames_to_column("car") |> arrange(mpg) |> slice_head(n = 10) |> ggplot(aes(x = mpg, y = reorder(car, mpg))) + geom_segment(aes(xend = 0, yend = car)) + geom_point(size = 3, color = "steelblue")

  

  





Tip
Combine geom_segment with geom_point for lollipop charts. The segment is the "stick"; the point is the "candy".



Five common patterns



1. Lollipop chart




  

    
RBar alternative

    
df |>
  ggplot(aes(category, value)) +
  geom_segment(aes(xend = category, yend = 0)) +
  geom_point(size = 3)

    

      
      
    

    

  

  





2. Arrow segment




  

    
RWith arrowhead

    
ggplot(df, aes(x = 0, y = 0, xend = 5, yend = 10)) +
  geom_segment(arrow = arrow(length = unit(0.3, "cm")))

    

      
      
    

    

  

  





3. Connect two points




  

    
RA-to-B segments

    
df <- tibble(x1 = 1:3, y1 = 1:3, x2 = 4:6, y2 = 4:6)
ggplot(df, aes(x = x1, y = y1, xend = x2, yend = y2)) +
  geom_segment()

    

      
      
    

    

  

  





4. Highlight reference lines




  

    
RVertical line at x = 5

    
ggplot(mtcars, aes(wt, mpg)) +
  geom_point() +
  geom_segment(aes(x = 5, y = 0, xend = 5, yend = max(mpg)),
               linetype = "dashed", color = "red")

    

      
      
    

    

  

  





5. Network-like edges




  

    
RConnect node positions

    
edges <- tibble(x1 = c(0, 1), y1 = c(0, 1), x2 = c(1, 2), y2 = c(1, 0))
ggplot(edges, aes(x = x1, y = y1, xend = x2, yend = y2)) +
  geom_segment()

    

      
      
    

    

  

  





Key Insight
geom_segment requires FOUR aesthetics: x, y, xend, yend. Each row draws ONE segment from (x, y) to (xend, yend).



geom_segment() vs geom_curve() vs geom_line()







Function
Path
Best for






geom_segment()
Straight line
Explicit endpoints




geom_curve()
Curved line
Arc connections




geom_line()
Connected points (sorted x)
Trends




geom_path()
Connected points (row order)
Trajectories







A practical workflow



Lollipop charts are a common alternative to bar charts and use geom_segment + geom_point.




  

    
RInteractive R

    
mtcars |>
  tibble::rownames_to_column("car") |>
  arrange(desc(mpg)) |>
  slice_head(n = 10) |>
  ggplot(aes(x = mpg, y = reorder(car, mpg))) +
  geom_segment(aes(xend = 0, yend = car), color = "grey") +
  geom_point(size = 4, color = "steelblue")

    

      
      
    

    

  

  





Common pitfalls



Pitfall 1: forgetting xend or yend. geom_segment requires all four aesthetics. Missing one errors.



Pitfall 2: arrow direction. arrow appears at the END (xend, yend) by default. Reverse aesthetics if direction is wrong.



Warning
geom_segment() does NOT close shapes. It draws ONE segment per row. For closed shapes, use geom_polygon.



Try it yourself





Try it: Make a lollipop chart of top 5 mtcars by mpg. Save to ex_plot.



  

    
RYour turn: lollipop

    
ex_plot <- mtcars |>
  tibble::rownames_to_column("car") |>
  arrange(desc(mpg)) |>
  slice_head(n = 5) |>
  # your code here

    

      
      
    

    

  

  





Click to reveal solution



  

    
RSolution

    
ex_plot <- mtcars |>
  tibble::rownames_to_column("car") |>
  arrange(desc(mpg)) |>
  slice_head(n = 5) |>
  ggplot(aes(x = mpg, y = reorder(car, mpg))) +
  geom_segment(aes(xend = 0, yend = car)) +
  geom_point(size = 3, color = "steelblue")

    

      
      
    

    

  

  





Explanation: Sort by mpg desc, take top 5, draw segment from 0 to mpg with point at the end.










After mastering geom_segment, look at:



    


  • geom_curve(): curved segments
    • 


  • arrow(): arrowhead specification
    • 


  • geom_path() / geom_line(): connected points
    • 


  • geom_vline() / geom_hline(): full-axis reference lines
    • 


  • annotate(): one-off annotations
    • 





FAQ



What does geom_segment do in ggplot2?



geom_segment() draws straight line segments from (x, y) to (xend, yend) for each row of data.



How do I add an arrow to geom_segment?



Pass arrow = arrow(length = unit(0.3, "cm")): geom_segment(arrow = arrow()). Arrow appears at (xend, yend).



What is the difference between geom_segment and geom_line?



geom_segment draws independent segments per row using xend/yend. geom_line connects points across rows with sorted x.



How do I make a lollipop chart?



Combine geom_segment (stick from baseline to value) with geom_point (candy at value).



What is the difference between geom_segment and geom_curve?



geom_segment is straight; geom_curve is curved. Same aesthetics; different visual.



          

        


        
      


      

        

        
© 2016-2026 Selva Prabhakaran.
          This work is licensed under the Creative Commons License.
        

        

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