plotly stacked area graph custom colours from named vector

November 22, 2022

I am trying to use custom colours with a dataset in Plotly. The named vector works from a line graph and other graphs, but doesn’t for the stacked area graph. Any ideas?

Also posted here: https://community.rstudio.com/t/plotly-stacked-area-graph-custom-colours-from-named-vector/153342

library(plotly)
library(tidyverse)
library(palmerpenguins) # for the dataset

penguins_cols <- c("Adelie" = "blue",
                   "Gentoo" = "red",
                   "Chinstrap" = "green")

# works for line graphs
plot_ly(penguins,
        colors = penguins_cols) %>%
  add_trace(x = ~bill_length_mm,
            y = ~bill_depth_mm,
            color = ~species,
            type = "scatter",
            mode = "lines+markers")


# doesn't work for area graphs
plot_ly(penguins,
        colors = penguins_cols) %>%
  add_trace(x = ~bill_length_mm,
            y = ~bill_depth_mm,
            fillcolor = ~species,
            mode = "none",
            stackgroup = 'one')

>Solution :

Perhaps there is more direct way but from the docs setting the colors via fillcolor seems to be the way to go, i.e. use fillcolor = ~penguins_cols[species] and set the names for the legend entries via name = ~species.

library(ggplot2)
library(plotly)
library(palmerpenguins)

penguins_cols <- c("Adelie" = "blue",
                   "Gentoo" = "red",
                   "Chinstrap" = "green")

plot_ly(penguins) %>%
  add_trace(x = ~bill_length_mm,
            y = ~bill_depth_mm,
            name = ~species,
            fillcolor = ~penguins_cols[species],
            mode = "none",
            type = "scatter",
            stackgroup = 'one')
#> Warning: Ignoring 2 observations