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I'm trying to produce a faceted ridgeplot, where some ridges are empty. The code below produces an example.

library(ggridges)
library(tidyverse)

df <- tibble(x = rnorm(1000, 1, 1),
             id = c(rep(1, 600), rep(2, 400)),
             year = c(rep(2000:2005, each = 100), rep(2000:2003, each = 100)))
df %>%
  ggplot(aes(x = x, y = as.factor(year))) + 
    geom_density_ridges2() +
    facet_grid(.~id) +
    geom_vline(xintercept = 0)

ggridges problem example

The vertical line here stretches through the years in facet 2 for which there is no data. How can I prevent this and stop it after 2003?

ADF
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1 Answers1

2

Not super pretty, but you could make a df/tibble to describe parameters for a geom_segment() for each year / id combo. You'd likely need to include some tweaks to clean up the area shown (like with coord_cartesian() as I've done here) but it may serve for what you need.

enter image description here

library(ggridges)
library(tidyverse)

set.seed(123)

df <- tibble(x = rnorm(1000, 1, 1),
             id = c(rep(1, 600), rep(2, 400)),
             year = c(rep(2000:2005, each = 100), rep(2000:2003, each = 100)))

seg_df <-
  data.frame(
    x0 = 0,
    x1 = 0,
    id = c(rep(1, 6), rep(2, 4)),
    year = c(2000:2005, 2000:2003)
  ) %>%
  group_by(id) %>%
  arrange(year) %>%
  mutate(y0 = row_number(), y1 = y0 + 1) %>%
  mutate(y0 = ifelse(y0 == 1, -1, y0)) %>%
  mutate(y1 = ifelse(y1 == max(y1), y1 + 1, y1))
seg_df

df %>%
  ggplot(aes(x = x, y = as.factor(year))) + 
  geom_density_ridges2() +
  facet_grid(.~id) +
  geom_segment(
    data = seg_df,
    mapping = aes(
      x = x0,
      xend = x1,
      y = y0,
      yend = y1
    ),
    inherit.aes = FALSE
  ) + coord_cartesian(ylim = c(1, length(unique(df$year)) + 1.2))
Luke C
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  • This solution is adequate. I was thinking of doing something similar by constructing a large legend that sat on top of that part of the plot... Still, I feel like there should be a more elegant way, or even that this should be the default behavior. – ADF Jul 06 '21 at 13:13