ggplot2: geom_bar with custom y limits

Question

I want to draw a bar chart with ggplot2 along with custom y limits.

Type <- LETTERS[1:5]
Y    <- c(99, 99.5, 99.0, 98.8, 98.5)

df <- data.frame(Type, Y)

The following code works fine for bar chart:

library(ggplot2)
ggplot(data = df, mapping = aes(x = Type, y = Y, fill = Type)) +
  geom_bar(stat = "identity") +
  theme_bw()

However, I'm not able to set the y limits. See the code below.

ggplot(data = df, mapping = aes(x = Type, y = Y, fill = Type)) +
  geom_bar(stat = "identity") +
  scale_y_continuous(limits = c(90, 100)) + 
  theme_bw()

ggplot(data = df, mapping = aes(x = Type, y = Y, fill = Type)) +
  geom_bar(stat = "identity") +
  ylim(90, 100) + 
  theme_bw()

Edited

I guess this behavior is due to stat = "identity".

I don't know if this is possible as `geom_bar` goes from `0` to `y` (its like inserting break in y axis). Why not to plot `geom_point`? — pogibas, Dec 23 '17 at 08:45
Thanks @PoGibas for your comment. Yes, `geom_point` could be another possibility. However, I want to show these points throw bars. Any thought. — MYaseen208, Dec 23 '17 at 08:49

score 10 · Answer 1 · answered Dec 23 '17 at 09:13

10

Alternative, using coord_cartesian:

ggplot(data = df, mapping = aes(x = Type, y = Y, fill = Type)) +
  geom_bar(stat = "identity") +
  coord_cartesian(ylim = c(90, 100)) + 
  theme_bw()

Gives you:

answered Dec 23 '17 at 09:13

Luke C

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This solution is more appealing. Thanks @Luke C for your nice answer. – MYaseen208 Dec 23 '17 at 09:15
This is what I was looking for with `coord_cartesian(ylim = range(df$Y))`. – MYaseen208 Dec 23 '17 at 09:19
1

@MYaseen208 - Good call, that's pretty slick. – Luke C Dec 23 '17 at 09:22

pogibas · Accepted Answer · 2017-12-23T09:15:03.067

5

Solution using geom_rect() instead of geom_bar():

# Generate data
Type <- LETTERS[1:5]
Y    <- c(99, 99.5, 99.0, 98.8, 98.5)
df   <- data.frame(Type, Y)

# Plot data
library(ggplot2)
ggplot() +
    geom_rect(data = df, 
              aes(xmin = as.numeric(Type) - 0.3, 
                  xmax = as.numeric(Type) + 0.3, 
                  ymin = 90, ymax = Y,
                  fill = Type)) +
    scale_x_continuous(label = df$Type, breaks = 1:nrow(df))

In geom_rect() specify x coordinates as as.numeric(X) -/+ value; ymin coordinates as wanted lower limit and ymax as actual Y values.

edited Dec 23 '17 at 09:15

answered Dec 23 '17 at 08:56

pogibas

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Thanks @PoGibas for useful answer. Would highly appreciate if you help me to remove the blank space below the rectangles so that y should start from 90. Thanks – MYaseen208 Dec 23 '17 at 09:11
@MYaseen208 you mean space between rectangles and ticks? – pogibas Dec 23 '17 at 09:12
1

yes the extra space between rectangles and x ticks. – MYaseen208 Dec 23 '17 at 09:14

ggplot2: geom_bar with custom y limits

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