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In this post we’ll quickly show how to create radial stacked ara charts in plotly. We’ll use the AirPassengers dataset.

Inspired by Mike Bostocks post: http://bl.ocks.org/mbostock/3048740

#devtools::install_github("ropensci/plotly")

library(plotly)
library(zoo)
library(data.table)

data("AirPassengers")

# Create data frame with year and month
AirPassengers <- zoo(coredata(AirPassengers), order.by = as.yearmon(index(AirPassengers)))
df <- data.frame(month = format(index(AirPassengers), "%b"),
year =  format(index(AirPassengers), "%Y"),
value = coredata(AirPassengers))

# Get coordinates for plotting
#Angles for each month
nMonths <- length(unique(df$month)) theta <- seq(0, 2*pi, by = (2*pi)/nMonths)[-(nMonths+1)] # Append these angles to the data frame df$theta <- rep(theta, nMonths)

# Cumulatively sum number of passgengers
dt <- as.data.table(df)
dt[,cumvalue := cumsum(value), by = month]
df <- as.data.frame(dt)

# Cartesian coordinates (x, y) space will be value*cos(theta) and value*sin(theta)
df$x <- df$cumvalue * cos(df$theta) df$y <- df$cumvalue * sin(df$theta)

# Create hovertext
df$hovertext <- paste("Year:", df$year, "<br>",
"Month:", df$month, "<br>", "Passegers:", df$value)

# Repeat January values
ddf <- data.frame()
for(i in unique(df$year)){ temp <- subset(df, year == i) temp <- rbind(temp, temp[1,]) ddf <- rbind(ddf, temp) } df <- ddf # Plot colorramp <- colorRampPalette(c("#bfbfbf", "#f2f2f2")) cols <- colorramp(12) cols <- rep(c("#e6e6e6", "#f2f2f2"), 6) linecolor <- "#737373" p <- plot_ly(subset(df, year == 1949), x = ~x, y = ~y, hoverinfo = "text", text = ~hovertext, type = "scatter", mode = "lines", line = list(shape = "spline", color = linecolor)) k <- 2 for(i in unique(df$year)[-1]){
p <- add_trace(p, data = subset(df, year == i),
x = ~x, y = ~y, hoverinfo = "text", text = ~hovertext,
type = "scatter", mode = "lines",
line = list(shape = "spline", color = linecolor),
fillcolor = cols[k], fill = "tonexty")

k <- k + 1
}

start <- 100
end <- 4350
axisdf <- data.frame(x = start*cos(theta), y = start*sin(theta),
xend = end*cos(theta), yend = end*sin(theta))

p <- add_segments(p = p, data = axisdf, x = ~x, y = ~y, xend = ~xend, yend = ~yend, inherit = F,
line = list(dash = "8px", color = "#737373", width = 4),
opacity = 0.7)

p <- add_text(p, x = (end + 200)*cos(theta), y = (end + 200)*sin(theta), text = unique(df\$month), inherit = F,
textfont = list(color = "black", size = 18))

p <- layout(p, showlegend = F,
title = "Radial Stacked Area Chart",
xaxis = list(showgrid = F, zeroline = F, showticklabels = F, domain = c(0.25, 0.80)),
yaxis = list(showgrid = F, zeroline = F, showticklabels = F),
length = 1024,
height = 600)

p