CODEWITHSUNDEEP
rggplot2
Brennan
Brennan

Reputation: 429

ggplot lwd overriding legend

I have a bit of a coding issue. I have a MWE below:

df <- data.frame(year=seq(1961,2013,1), group1=rnorm(53), group2=rnorm(53))
p <- ggplot(df, aes(x=year)) +
  geom_line(aes(y=group1, linetype="group1")) +
  geom_line(aes(y=group2, linetype="group2"))

p1 <- ggplot(df, aes(x=year)) +
  geom_line(aes(y=group1, linetype="group1"), lwd=1.5) +
  geom_line(aes(y=group2, linetype="group2"))

p produces a very standard looking graph with no issues:

enter image description here

However, when I try to change the linewidth in p1, of one of the geom_line, this distorts the legend as such:

enter image description here

The dotted aspect of the line remains the same but the lined segment is being affected by the lwd=1.5 from the first line.

Is there an error/shortcoming in my approach to this problem or a larger issue at play here?

Upvotes: 1

Views: 346

Answers (1)

stefan
stefan

Reputation: 125478

If you want a nice legend with different linetypes and linewidths then you should convert your data to long format, map group on both linetype and lwd aestehtics and set the lwd manually using scale_size_manual.

library(ggplot2)
library(dplyr)
library(tidyr)

df <- data.frame(year=seq(1961,2013,1), group1=rnorm(53), group2=rnorm(53))

df %>% 
  pivot_longer(-year, names_to = "group") %>% 
  ggplot(aes(x=year)) +
  geom_line(aes(y=value, linetype = group, lwd = group)) +
  scale_size_manual(values = c(1.5, .5))

Created on 2020-05-27 by the reprex package (v0.3.0)

Upvotes: 1

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