CODEWITHSUNDEEP
rggplot2tidyverselegend
Jiaqi Ding
Jiaqi Ding

Reputation: 11

Merge legend from different geom and aes?

the idea is simple:
(1)Use red dot for actual data;
(2)Use blue dashed line for fitted value.
But I just could not find a way to make such legend.

My fig and code below: fig

library(ggplot)
x <- seq(1,100,1)
y <- 2*x + runif(100,-5,5)
fit_y <- 2*x

df <- data.frame(x=x, y=y,fit_y=fit_y)
df

ggplot(df)+
  geom_point(aes(x=x, y=y, color='point', shape='point'))+
  geom_line(aes(x=x, y=fit_y, color='line', linetype='line')) +
  scale_color_manual(values=c('point'='red', 'line'='blue')) +
  scale_linetype_manual(values = c('line'='longdash')) +
  scale_shape_manual(values = c('point'=1 ))

And I am pretty confused about that: Why is color legend composed of line and point?
Now it is a "blue line + blue point" PLUS "red line + red point".
But I only assign red to geom_point and blue to geom_line! Why is this?

Upvotes: 1

Views: 379

Answers (3)

teunbrand
teunbrand

Reputation: 37933

Perhaps the best way is to not bother mapping aesthetics for shape and linetype at all, and instead overriding the display of the colour legend directly. This is also the suggested workaround for guides indiscriminately applying glyphs for every key.

library(ggplot2)
x <- seq(1,100,1)
y <- 2*x + runif(100,-5,5)
fit_y <- 2*x

df <- data.frame(x=x, y=y,fit_y=fit_y)

ggplot(df)+
  geom_point(aes(x=x, y=y, color='point'),
             shape = 1)+
  geom_line(aes(x=x, y=fit_y, color='line', linetype='line'),
            linetype = 'longdash') +
  scale_color_manual(
    values=c('point'='red', 'line'='blue'),
    guide = guide_legend(
      override.aes = list(
        shape = c(1, NA),
        linetype = c(NA, 5)
      )
    )
  )

Created on 2021-05-17 by the reprex package (v1.0.0)

Upvotes: 1

DS_UNI
DS_UNI

Reputation: 2650

is this what you're looking for?

ggplot(df)+
  geom_point(aes(x=x, y=y, color="real"), shape=1)+
  geom_line(aes(x=x, y=fit_y, linetype="estimate"), color="blue") +
  scale_color_manual(name="", values=c(real="red")) +
  scale_linetype_manual(name="", values = c(estimate="longdash")) +
  theme(legend.position="bottom")

enter image description here

The issue is that they are not really combined, they are still two separate legends, which is why I add the legend at the bottom, it looks more like one legend

Upvotes: 0

furkan_karamehmetoglu
furkan_karamehmetoglu

Reputation: 1

If I'm not mistaken, you want your data to be blue dots and your fitted value to be red dashed line.

I tried to make some adjustments on your code like following:

ggplot(df)+
geom_point(aes(x=x, y=y, color='point', shape='point'))+
geom_line(aes(x=x, y=fit_y, color='line', linetype='line')) +
scale_color_manual(values=c('point'='blue', 'line'='red')) +
scale_linetype_manual(values = c('line'='longdash')) +
scale_shape_manual(values = c('point'=1 ))

And so that I got following graph:

image

Upvotes: 0

Related Questions