Align ridgeplots

Question

I have created two separate ridgeplots in R using the ggridge package and the stat_density_ridges() function. My dataset includes a series of Latitude and Longitude locations. I have produced one ridgeplot for Latitute and one for Longitude and they are perfectly fine on their own. I have then used the function plot_grid() from the package cowplot to arrange the two plots horizontally. The two plots are aligned in terms of plot area but the x axes are not. Also, the spacing between plots is quite large and I would prefer reducing it rather than editing it manually.

My code is:

#load the necessary libraries
library(readr)
library(ggplot2)
library(ggridges)
library(cowplot)
library(RColorBrewer)

#load the data into a data.frame object
data <- as.data.frame(read_csv(file.choose()))
#View(data)

#calculate min and max latitude and longitude
minlat <- min(data$lat)
maxlat = max(data$lat)
minlon <- min(data$lon)
maxlon = max(data$lon)

#define the color palette to match the number of groups in the dataset
nb.cols <- 18
mycolors <- colorRampPalette(brewer.pal(9, "YlGnBu"))(nb.cols)

#make the latitude ridgeplot
r.plot.lat <-
  ggplot(data, aes(x = lat, y = species_group, fill = species_group)) +
  stat_density_ridges(
    alpha = 0.75,
    scale = 5,
    panel_scaling = T,
    size = 0.6,
    linetype = 1,
    colour = "darkgrey",
    quantile_lines = F,
    rel_min_height = 0.01
  ) +
  theme_ridges(font_size = 18) +
  theme(legend.position = "none") +
  xlab("Latitude") +
  ylab("") +
  scale_fill_manual(values = mycolors) +
  scale_x_discrete(limits=seq(round(minlat,0),round(maxlat,0), 2))

r.plot.lat

#make the longitude ridgeplot
r.plot.lon <-
  ggplot(data, aes(x = lon, y = species_group, fill = species_group)) +
  stat_density_ridges(
    alpha = 0.75,
    scale = 5,
    panel_scaling = T,
    size = 0.6,
    linetype = 1,
    colour = "darkgrey",
    quantile_lines = F,
    rel_min_height = 0.01
  ) +
   theme_ridges(font_size = 18) +
  theme(legend.position = "none") +
  xlab("Longitude") +
  ylab("")+
  theme(axis.text.y=element_blank()) +
  scale_fill_manual(values = mycolors) +
  scale_x_discrete(limits=seq(round(minlon,1),round(maxlon,1), 5))

r.plot.lon

#arrange the plots horizontally
plot_grid(r.plot.lat, NULL, r.plot.lon, align = "hv", labels=c("AUTO"), rel_widths = c(3, 0, 3), nrow=1)

The resulting plot is (I have blurred the Y axes on purpose, the plot is going into a paper to be submitted for publication):

I thought it was a problem of bandwidth so I have specified the same value for each plot in the bandwidth argument in the stat_density_ridges() function. Still not aligned.

EDIT Following @Quinten request, here is an example of 60 random records from my dataset.

    structure(list(species_group = c("Species_1", "Species_2", "Species_3", 
"Species_4", "Species_5", "Species_2", "Species_6", "Species_7", 
"Species_2", "Species_2", "Species_8", "Species_9", "Species_8", 
"Species_9", "Species_8", "Species_10", "Species_2", "Species_6", 
"Species_3", "Species_1", "Species_1", "Species_1", "Species_10", 
"Species_8", "Species_2", "Species_2", "Species_11", "Species_2", 
"Species_2", "Species_3", "Species_3", "Species_2", "Species_2", 
"Species_1", "Species_5", "Species_6", "Species_3", "Species_11", 
"Species_5", "Species_8", "Species_2", "Species_2", "Species_8", 
"Species_2", "Species_11", "Species_12", "Species_9", "Species_3", 
"Species_5", "Species_13", "Species_11", "Species_9", "Species_3", 
"Species_2", "Species_1", "Species_5", "Species_1", "Species_3", 
"Species_7", "Species_3"), lat = c(39.29652333333, 38.69591833333, 
43.78736, 42.88574333333, 38.51973, 40.06572, 37.36825, 41.06519666667, 
38.18816166667, 36.31976333333, 42.37949166667, 38.66838666667, 
40.72673833333, 36.75656833333, 40.47298333333, 41.720205, 36.14439333333, 
36.64385666667, 35.40855333333, 40.5198, 42.94889333333, 35.99670666667, 
39.967185, 39.37684333333, 39.68108666667, 35.84022166667, 39.45906833333, 
38.6217, 36.79680166667, 39.819615, 36.36867666667, 40.399535, 
36.28853, 42.11886, 40.43070833333, 39.200125, 36.90197, 37.47650833333, 
38.10325666667, 41.64378333333, 34.68400166667, 40.42848333333, 
38.52368166667, 36.15304166667, 36.88089333333, 38.7511, 37.15612666667, 
41.83358833333, 39.90101833333, 39.90281, 36.207415, 44.05422166667, 
44.02940666667, 36.873425, 39.91606166667, 42.93375166667, 39.68787833333, 
38.57978166667, 39.72445333333, 38.77966), lon = c(5.92169333333, 
10.60350166667, 9.29786666667, 7.91347833333, 17.63931166667, 
3.12386166667, 23.40353, 12.51722833333, 11.13067333333, -6.91365, 
15.645445, 10.63217166667, 1.70525666667, -1.71539666667, 1.47485833333, 
3.81735666667, -2.61197833333, -7.662125, 12.72044666667, 5.24996, 
10.23093833333, -5.369945, 17.42619666667, 4.91467166667, 1.518235, 
-6.721575, 0.70451333333, 19.47572333333, -1.51764666667, 17.444935, 
-6.83558166667, 6.89818, -6.96372, 6.03615833333, 3.20266, 0.79276166667, 
-0.75958833333, 2.97557333333, 1.92862666667, 19.300375, 29.77435166667, 
6.52557, 19.43436333333, -4.59611666667, 0.77969, 2.05171833333, 
-0.81246833333, 7.34824, 1.64478333333, 11.36721, -3.84277166667, 
8.53026833333, 9.25958, 0.78068, 1.62469, 3.64922666667, 0.81624166667, 
17.63248166667, 10.09109666667, 10.969315), type = c("groups", 
"groups", "species", "species", "groups", "groups", "species", 
"groups", "groups", "groups", "groups", "groups", "groups", "groups", 
"groups", "groups", "groups", "species", "species", "groups", 
"groups", "groups", "groups", "groups", "groups", "groups", "groups", 
"groups", "groups", "species", "species", "groups", "groups", 
"groups", "groups", "species", "species", "groups", "groups", 
"groups", "groups", "groups", "groups", "groups", "groups", "groups", 
"groups", "species", "groups", "species", "groups", "groups", 
"species", "groups", "groups", "groups", "groups", "species", 
"groups", "species")), row.names = c(NA, -60L), class = "data.frame")

Could you please share some reproducible data using `dput`? So we can reproduce your problem and help you better. — Quinten, Apr 21 '23 at 10:23
I have added 60 random rows from my dataframe, I have plotted the data and the issue is clearly visible — Nino Pierantonio, Apr 21 '23 at 11:10
To reduce space between the plots, you can give a negative relative width to the `NULL` plot in `plot_grid()`. I couldn't figure out how to align the x-axes, but I my guess is that they differ due to differing heights of the individual ridges. As an alternative, you could use `facet_grid()` with `nrow = 1` while making a singular plot, although this will look a bit different than the result you asked for. I could provide an example if you prefer. — rjjanse, Apr 21 '23 at 11:56

stefan · Answer 1 · 2023-04-21T16:55:57.143

One option to fix your issue would be to use facetting which requires to reshape your data but simplifies your code as we only have to create "one" plot. Additionally I use theme options to get rid of the facet look.

# load the necessary libraries
library(ggplot2)
library(ggridges)
library(RColorBrewer)

nb.cols <- 18
mycolors <- colorRampPalette(brewer.pal(9, "YlGnBu"))(nb.cols)

data |>
  tidyr::pivot_longer(c(lat, lon)) |>
  ggplot(aes(x = value, y = species_group, fill = species_group)) +
  stat_density_ridges(
    alpha = 0.75,
    scale = 5,
    panel_scaling = TRUE,
    size = 0.6,
    linetype = 1,
    colour = "darkgrey",
    quantile_lines = FALSE,
    rel_min_height = 0.01
  ) +
  labs(x = NULL, y = NULL) +
  scale_fill_manual(values = mycolors) +
  facet_wrap(~name,
    strip.position = "bottom",
    scales = "free_x",
    labeller = labeller(name = c(lat = "Latitude", lon = "Longitude"))
  ) +
  theme_ridges(font_size = 18) +
  theme(
    legend.position = "none",
    strip.background.x = element_blank(),
    strip.placement = "outside"
  )

this worked perfectly, thanks ever so much for the help. I am not actually sure how to use faceting in this specific case, but that's a great solution,thanks. — Nino Pierantonio, Apr 24 '23 at 14:56

Align ridgeplots

1 Answers1