CODEWITHSUNDEEP
rggplot2
KLee
KLee

Reputation: 205

ggplot2: Size of two vertical lines at the end in geom_errorbarh

I currently have the figure shown below:

enter image description here

However, two vertical lines at the end of (horizontal) line is too long for me. I tried to change the number for both "height" and "width", but changing the number did not work.

Can anyone make the vertical lines shorter?

Many thanks in advance!

*** Here is the code that can reproduce the plot.

my_data <- data.frame(mean = c(0.04, 0.015, -0.04),
                      stdev = c(0.019,  0.019, 0.02), 
                      Type = factor(c("A", 
                                      "B",
                                      "C")))
# points at which to evaluate the Gaussian densities
x <- seq(-0.1, 0.1, by = 0.001)

# build list of Gaussian density vectors based on means and standard deviations
pdfs <- mapply(dnorm, mean = my_data$mean, sd = my_data$stdev, MoreArgs = list(x = x),
               SIMPLIFY = FALSE)

# add group names
names(pdfs) <- my_data$Type

# convert list to dataframe
pdfs <- do.call(cbind.data.frame, pdfs)

# Summary stat
x.com <- data.frame(pdfs, x)
sum_stat <- matrix(NA, ncol = 4, nrow = 3)
for (i in 1:3){
  sum_stat[i,1] <- qnorm(0.025 , mean=my_data[i,1], sd=my_data[i,2])
  sum_stat[i,2] <- x.com[,4][x.com[,i]==max(x.com[,i])]
  sum_stat[i,3] <- qnorm(0.975, mean=my_data[i,1], sd=my_data[i,2])
}
sum_stat <- data.frame(sum_stat)
sum_stat[,4] <- colnames(x.com)[1:3]
sum_stat[,4] <- as.factor(sum_stat[,4])
colnames(sum_stat) <- c("left", "max", "right", "Type")
colnames(sum_stat)[4] <- "Type"

# convert dataframe to tall format
# library(tidyr)
pdfs$x <- x
tall_df <- gather(pdfs, Type, density, -x)
tall_df$Type

tt <- transform(tall_df,
                Type=factor(Type,levels=c("A", 
                                          "B",
                                          "C")))

ggplot(tt) + 
  # geom_line(aes(x = x, y = density, color = Type)) +
  geom_point(data = sum_stat, 
             aes(x = max, y = 0, alpha=0.4),
             show.legend = FALSE, color = "black") +

  geom_errorbarh(data = sum_stat, 
                 aes(xmin = left, xmax = right, y = 0, alpha=0.4),
                 height = 0.01, show.legend = FALSE, color = "black") +

  facet_wrap(~ Type, ncol = 1) +
  theme(strip.background = element_blank(),
        strip.text.x = element_blank())

Update:

I am updating the post, because I cannot show you what my Console says. I cleared the the global environment, and then run the code that I attached here. I do not have any problem running it. In my case, the head and tail of tt look like this:

> tt <- transform(tall_df,
+                 Type=factor(Type,levels=c("A", 
+                                           "B",
+                                           "C")))
> head(tt)
       x Type      density
1 -0.100    A 3.407570e-11
2 -0.099    A 5.014963e-11
3 -0.098    A 7.360166e-11
4 -0.097    A 1.077220e-10
5 -0.096    A 1.572238e-10
6 -0.095    A 2.288385e-10
> tail(tt)
        x Type      density
598 0.095    C 2.547469e-09
599 0.096    C 1.815481e-09
600 0.097    C 1.290591e-09
601 0.098    C 9.151661e-10
602 0.099    C 6.473296e-10
603 0.100    C 4.567360e-10

One thing that I wanted to mention is: I would like to keep the range of y, but just make the vertical lines at the end of errorbar shorter.

Upvotes: 2

Views: 482

Answers (1)

stefan
stefan

Reputation: 125028

Fix the scale of your y-axis, e.g. add + scale_y_continuous(limits = c(-.2, .2)). Then you can adjust the length of the vertical lines with height. Otherwise ggplot2 always readjusts the scale of the y-axis to the chosen height so that it appears as if height has no impact at all.

ggplot(tt) + 
  # geom_line(aes(x = x, y = density, color = Type)) +
  geom_point(data = sum_stat, 
             aes(x = max, y = 0, alpha=0.4),
             show.legend = FALSE, color = "black") +
  geom_errorbarh(data = sum_stat, 
                 aes(xmin = left, xmax = right, y = 0, alpha=0.4),
                 height = 0.01, show.legend = FALSE, color = "black") +
  scale_y_continuous(limits = c(-.2, .2)) +
  facet_wrap(~ Type, ncol = 1) +
  theme(strip.background = element_blank(),
        strip.text.x = element_blank())

Created on 2020-03-11 by the reprex package (v0.3.0)

Upvotes: 2

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