Horizontal side by side choropleth subplots do not work

Question

I want to have two r plotly choropleth plots in one subplot horizontally (side by side), but nrow=1 does not work, instead they appear vertically (above each other):

library(plotly)
df <- read.csv("https://raw.githubusercontent.com/plotly/datasets/master/2011_us_ag_exports.csv")

g <- list(
  scope = 'usa',
  projection = list(type = 'albers usa'),
  showlakes = TRUE,
  lakecolor = toRGB('white')
)

p1 <- plot_ly(z = df$beef, text = df$hover, locations = df$code, type = 'choropleth', locationmode = 'USA-states', color = df$beef, colors = 'Purples',
              colorbar = list(title = "Millions USD")) %>% layout(geo = g)

p2 <- plot_ly(z = df$pork, text = df$hover, locations = df$code, type = 'choropleth', locationmode = 'USA-states', color = df$pork, colors = 'Purples',
              colorbar = list(title = "Millions USD"), geo = 'geo2') %>% layout(geo2 = g)


plotly::subplot(p1, p2, nrows = 1)

How can I fix (have them above each other than side by side)? And how can I have one common legend/colorbar?

Answer 1

Simply use "domain" to let nrows work.

g <- list(
  scope = 'usa',
  projection = list(type = 'albers usa'),
  showlakes = TRUE,
  lakecolor = toRGB('white'),
  domain = list(x = c(0, 1), y = c(0, 1))
)

p1 <- plot_ly(z = df$beef, locations = df$code, type = 'choropleth', locationmode = 'USA-states', 
              color = df$beef, colors = 'Purples',
              colorbar = list(title = "Millions USD"), showscale = F) %>% layout(geo = g)
p2 <- plot_ly(z = df$pork, locations = df$code, type = 'choropleth', locationmode = 'USA-states', 
              color = df$pork, colors = 'Greens',
              colorbar = list(title = "Millions USD"), showscale = F, geo = 'geo2') %>% layout(geo2 = g)
p3 <- plot_ly(z = df$corn, locations = df$code, type = 'choropleth', locationmode = 'USA-states', 
              color = df$corn, colors = 'Blues',
              colorbar = list(title = "Millions USD"), showscale = F, geo = 'geo3') %>% layout(geo3 = g)
p4 <- plot_ly(z = df$cotton, locations = df$code, type = 'choropleth', locationmode = 'USA-states', 
              color = df$cotton, colors = 'Oranges',
              colorbar = list(title = "Millions USD"), showscale = F, geo = 'geo4') %>% layout(geo4 = g)

subplot(p1, p2, p3, p4, nrows = 2)

This renders:

Still have not found a way to share a colorbar for the subplots, so I hide them by 'showscale = F' and use different colors instead.