Filled Area in ggplot2

How to make Filled Area Plots in ggplot2 with Plotly.

New to Plotly?

Plotly is a free and open-source graphing library for R. We recommend you read our Getting Started guide for the latest installation or upgrade instructions, then move on to our Plotly Fundamentals tutorials or dive straight in to some Basic Charts tutorials.

Basic stacked area plot

The data frame used as input to build a stacked area chart requires 3 columns: * x: numeric variable used for the X axis, often it is a time. * y: numeric variable used for the Y axis. What are we looking at? * group: one shape will be done per group.

The chart is built using the geom_area() function.

library(plotly)
library(ggplot2)
library(dplyr)

time <- as.numeric(rep(seq(1,7),each=7))
value <- runif(49, 10, 100)
group <- rep(LETTERS[1:7],times=7)
data <- data.frame(time, value, group)

p <- ggplot(data, aes(x=time, y=value, fill=group)) + 
    geom_area()

ggplotly(p)

Control stacking order

The gallery offers a post dedicated to reordering with ggplot2. This step can be tricky but the code below shows how to:

give a specific order with the factor() function.
order alphabetically using sort()
order following values at a specific data

library(plotly)
library(ggplot2)
library(dplyr)

time <- as.numeric(rep(seq(1,7),each=7))
value <- runif(49, 10, 100)
group <- rep(LETTERS[1:7],times=7)
data <- data.frame(time, value, group)

data$group <- factor(data$group , levels=c("B", "A", "D", "E", "G", "F", "C") )

p <- ggplot(data, aes(x=time, y=value, fill=group)) + 
    geom_area()

ggplotly(p)

Proportional stack

In a proportional stacked area graph, the sum of each year is always equal to hundred and value of each group is represented through percentages.

library(plotly)
library(ggplot2)
library(dplyr)
data <- data  %>%
  group_by(time, group) %>%
  summarise(n = sum(value)) %>%
  mutate(percentage = n / sum(n))

p <- ggplot(data, aes(x=time, y=percentage, fill=group)) + 
    geom_area(alpha=0.6 , size=1, colour="black")

ggplotly(p)

What About Dash?

Dash for R is an open-source framework for building analytical applications, with no Javascript required, and it is tightly integrated with the Plotly graphing library.

Learn about how to install Dash for R at https://dashr.plot.ly/installation.

Everywhere in this page that you see fig, you can display the same figure in a Dash for R application by passing it to the figure argument of the Graph component from the built-in dashCoreComponents package like this:

library(plotly)

fig <- plot_ly() 
# fig <- fig %>% add_trace( ... )
# fig <- fig %>% layout( ... ) 

library(dash)
library(dashCoreComponents)
library(dashHtmlComponents)

app <- Dash$new()
app$layout(
    htmlDiv(
        list(
            dccGraph(figure=fig) 
        )
     )
)

app$run_server(debug=TRUE, dev_tools_hot_reload=FALSE)