Plot x vs y with two values in y

Question

I fitted a model and want to do a plot of observation number in x-axis and fitted in y-axis with observed value of y in y-axis too with ggplot2, something like this. I can't use colours then I need different symbols for observed and predicted.

observed <- c(0.1,0.32,0.42,0.27,0.9,0.8)
fitted <- c(0.19,0.31,0.41,0.26,0.81,0.77)
x <- c(1,2,3,4,5,6)

So basically what I want to do is put to each x the two values in y-axis (observed and fitted) with different symbols.

score 2 · Answer 1 · answered Apr 25 '17 at 00:14

2

You can use simple base graphics to get two different plotting characters

plot(x, observed, pch=15)
points(x, fitted, pch=17)

answered Apr 25 '17 at 00:14

MrFlick

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Is there a way to put a legend in the right side with this simple plot ? – Roland Apr 25 '17 at 00:21
Take a look at the `?legend` function. – MrFlick Apr 25 '17 at 00:21

alistaire · Accepted Answer · 2017-05-24T17:14:33.557

With ggplot, make a data.frame first:

library(tidyverse)

df <- data.frame(observed = c(0.1,0.32,0.42,0.27,0.9,0.8),
                 fitted = c(0.19,0.31,0.41,0.26,0.81,0.77),
                 x = c(1,2,3,4,5,6))

Then you can plot each set of values separately, with some extra specification to get shapes:

ggplot(df) + 
    geom_point(aes(x, observed, shape = 'observed')) + 
    geom_point(aes(x, fitted, shape = 'fitted'))

...or in an approach that will scale better, reshape to long form first with tidyr::gather:

df %>% gather(value, val, -x) %>% 
    ggplot(aes(x, val, shape = value)) + 
    geom_point()

Plot x vs y with two values in y

2 Answers2