CODEWITHSUNDEEP
rggplot2
nouse
nouse

Reputation: 3471

plotting geom_text at individual positions in each facet of facet_wrap

I have this dataset

df <- data.frame(groups=factor(c(rep("A",6), rep("B",6), rep("C",6))),
                 types=factor(c(rep(c(rep("Z",2), rep("Y",2), rep("X",2)),3))),
                 values=c(10,11,1,2,0.1, 0.2, 12,13, 2,2.5, 0.2, 0.01, 
                          12,14, 2,3,0.1,0.2))
library(ggplot2)
px <- ggplot(df, aes(groups, values)) + facet_wrap(~types, scale="free") + geom_point()
px

i conducted post-hoc analysis (values~groups for each level of types) and created a dataset, which contains significance groups (as letters: a, b, c and so on):

df.text <- data.frame(groups=factor(c(rep("A",3), rep("B",3), rep("C",3))),
                      label=rep("a", 9))

i proceeded to plot the labels on px:

px + geom_text(data=df.text, aes(x=groups, y=0.1, label=label), size=4, col="red", stat="identity") +theme_bw()

which doesnt look great.

My problem is to define a aes(y) in geom_text, which plots the labels at at a fixed position (e.g. above the x-axis or on top of the panel), without shifting the limits of the y axis too much. With previous datasets, the y-values were quite homogeneous among groups, so i could get away with a very low y-value. This time however the range of y is quite high, so its not easily getting done.

So, the question is how to plot the labels inside df.text at a fixed position in facet_wrap, while keeping scale="free". Best would be above the top panel.border.

Upvotes: 2

Views: 2293

Answers (1)

dave-edison
dave-edison

Reputation: 3736

You could define a new variable height which determines the height to plot the labels:

library(tidyverse)

df %>% 
  group_by(types) %>% 
  mutate(height = max(values) + .3 * sd(values)) %>% 
  left_join(df.text, by = "groups") %>% 
  ggplot(aes(groups, values)) + 
  facet_wrap(~types, scale = "free") + 
  geom_point() +
  geom_text(aes(x = groups, y = height, label = label), size = 4, col = "red", stat = "identity") +
  theme_bw()

Here I used the max value plus .3 times the standard deviation but you could change that to whatever you wanted obviously. Not sure how to get the labels on top of the panel strips though.

Upvotes: 4

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