I apologise if this has been asked before. I am trying to add median values to the peak of a grouped
density plot (example below).
library(dplyr)
library(forcats)
Catalan_elections %>%
mutate(YearFct = fct_rev(as.factor(Year))) %>%
ggplot(aes(y = YearFct))
geom_density_ridges(
aes(x = Percent, fill = paste(YearFct, Option)),
alpha = .8, color = "white", from = 0, to = 100
)
labs(
x = "Vote (%)",
y = "Election Year",
title = "Indy vs Unionist vote in Catalan elections",
subtitle = "Analysis unit: municipalities (n = 949)",
caption = "Marc Belzunces (@marcbeldata) | Source: Idescat"
)
scale_y_discrete(expand = c(0, 0))
scale_x_continuous(expand = c(0, 0))
scale_fill_cyclical(
breaks = c("1980 Indy", "1980 Unionist"),
labels = c(`1980 Indy` = "Indy", `1980 Unionist` = "Unionist"),
values = c("#ff0000", "#0000ff", "#ff8080", "#8080ff"),
name = "Option", guide = "legend"
)
coord_cartesian(clip = "off")
theme_ridges(grid = FALSE)
CodePudding user response:
Edit:
Thanks for updating your question; I misunderstood and thought you wanted to highlight the medians (straightforward) but it sounds like you actually want the peaks (more complicated). I also thought that this was your code, not an example from https://cran.r-project.org/web/packages/ggridges/vignettes/gallery.html, so I didn't realise the Catalan_elections dataset was publicly available (e.g. from the ggjoy package).
Here is a more relevant solution:
library(tidyverse)
library(palmerpenguins)
library(ggridges)
#install.packages("ggjoy")
library(ggjoy)
Catalan_elections_with_max_density <- Catalan_elections %>%
group_by(Year, Option) %>%
na.omit() %>%
mutate(max_density = max(density(Percent, na.rm = TRUE)$y),
which_max_density = which.max(density(Percent, na.rm = TRUE)$y)) %>%
mutate(which_max_x_intercept = density(Percent, na.rm = TRUE)$x[which_max_density])
Catalan_elections_with_max_density %>%
mutate(YearFct = fct_rev(as.factor(Year))) %>%
ggplot(aes(y = YearFct))
geom_density_ridges(
aes(x = Percent, fill = paste(YearFct, Option)),
alpha = .8, color = "white", from = 0, to = 100,
)
geom_segment(aes(x = which_max_x_intercept,
xend = which_max_x_intercept,
y = as.numeric(YearFct),
yend = as.numeric(YearFct) max_density * 48),
color = "white", size = 0.75, alpha = 0.1)
labs(
x = "Vote (%)",
y = "Election Year",
title = "Indy vs Unionist vote in Catalan elections",
subtitle = "Analysis unit: municipalities (n = 949)",
caption = "Marc Belzunces (@marcbeldata) | Source: Idescat"
)
scale_y_discrete(expand = c(0, 0))
scale_x_continuous(expand = c(0, 0))
scale_fill_cyclical(
breaks = c("1980 Indy", "1980 Unionist"),
labels = c(`1980 Indy` = "Indy", `1980 Unionist` = "Unionist"),
values = c("#ff0000", "#0000ff", "#ff8080", "#8080ff"),
name = "Option", guide = "legend"
)
coord_cartesian(clip = "off")
theme_ridges(grid = FALSE)
#> Picking joint bandwidth of 3.16
Created on 2021-12-14 by the reprex package (v2.0.1)
NB. I don't really understand how the scaling works in geom_density_ridges(), so I used "max_density * a constant" to get it approximately correct. Depending on your use-case you will need to adjust the constant or work out how the peak density relates to the y coordinates of the plot.
Original answer:
I don't have your dataset "Catalan_elections", so here is an example using the palmerpenguins dataset:
library(tidyverse)
library(palmerpenguins)
library(ggridges)
penguins %>%
na.omit() %>%
mutate(YearFct = fct_rev(as.factor(year))) %>%
ggplot(aes(x = bill_length_mm, y = YearFct, fill = YearFct))
geom_density_ridges(
alpha = .8, color = "white", from = 0, to = 100,
quantile_lines = TRUE, quantiles = 2
)
labs(
x = "Vote (%)",
y = "Election Year",
title = "Indy vs Unionist vote in Catalan elections",
subtitle = "Analysis unit: municipalities (n = 949)",
caption = "Marc Belzunces (@marcbeldata) | Source: Idescat"
)
scale_y_discrete(expand = c(0, 0))
scale_x_continuous(expand = c(0, 0))
scale_fill_cyclical(
breaks = c("1980 Indy", "1980 Unionist"),
labels = c(`1980 Indy` = "Indy", `1980 Unionist` = "Unionist"),
values = c("#ff0000", "#0000ff", "#ff8080", "#8080ff"),
name = "Option", guide = "legend"
)
coord_cartesian(clip = "off")
theme_ridges(grid = FALSE)
#> Picking joint bandwidth of 1.92
Created on 2021-12-13 by the reprex package (v2.0.1)