ggplot with both `geom_vline` and `geom_hline`. Task: need separate legends - r

Question

library(tidyverse)
library(lubridate)
y <- rnorm(100)
df <- tibble(y) %>%
mutate(os = factor(rep_len(1:5, 100)),
date = seq(from = ymd('2013-01-01'), by = 1, length.out = 100))
ggplot(df, aes(x = date, y = y, colour = os)) +
geom_line() +
geom_vline(
aes(xintercept = min(date), linetype = 'os 1'),
colour = 'red') +
geom_vline(
aes(xintercept = median(date), linetype = 'os 2'),
colour = 'blue') +
geom_hline(
aes(yintercept = 1, linetype = "dashed"),
colour = "black"
) +
scale_linetype_manual(
name = 'lines',
values = c('os 1' = 1, 'os 2' = 1),
guide = guide_legend(override.aes = list(colour = c('red', 'blue'))))
output:
What is wrong with output:
The geom_hline is missing.
The legend combines the vline and the hline to form a cross.
Correct output:
THe geom_hline should be drawn.
Need a separate legend for the vlines and hlines. i.e., lines in the vline legend should be vertical while lines in the hline legend should be horizontal.

Answer 1

This could be achieved by
Adding the hline to scale_linetype_manual
Making use of a custom key glyph as in this answer.
library(tidyverse)
library(lubridate)
set.seed(123)
y <- rnorm(100)
df <- tibble(y) %>%
mutate(os = factor(rep_len(1:5, 100)),
date = seq(from = ymd('2013-01-01'), by = 1, length.out = 100))
draw_key_cust <- function(data, params, size) {
if (data$colour %in% c("red", "blue"))
draw_key_vpath(data, params, size)
else
draw_key_path(data, params, size)
}
ggplot(df, aes(x = date, y = y, colour = os)) +
geom_line() +
geom_vline(
aes(xintercept = min(date), linetype = 'os 1'),
colour = 'red', key_glyph = "cust") +
geom_vline(
aes(xintercept = median(date), linetype = 'os 2'),
colour = 'blue', key_glyph = "cust") +
geom_hline(
aes(yintercept = 1, linetype = "dashed"),
colour = "black", key_glyph = "cust"
) +
scale_linetype_manual(
name = 'lines',
values = c('os 1' = 1, 'os 2' = 1, dashed = 2),
guide = guide_legend(override.aes = list(colour = c('red', 'blue', 'black'))))