Streamgraphs in ggplot2 with ggstream

Package

Author

David Sjoberg

Sample data

Consider the blockbusters data set from the ggstream package for this guide.

# install.packages("ggstream")
library(ggstream)

blockbusters

Stream plots in ggplot2 with `geom_stream`

The geom_stream function of the ggstream package allows creating streamplots in ggplot2. Input your data and use the function to create a basic stream graph.

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream()

Stream graph in ggplot2

Adding labels to the areas

Note that the package contains an additional function named geom_stream_label that can be used to add labels to each area of the streamgraph.

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream() +
  geom_stream_label(aes(label = genre))

Streamgraph with labels in R

Stream graphs types

By default, the geom_stream function uses the "mirror" type, which stacks the streams symmetrically around the X-axis. The other alternatives are "ridge", which stacks from the X-axis and "proportional", which makes the streams sum up to 1.

Ridge stream graph in ggplot2

Ridge

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(type = "ridge")

Proportional streamplot in R

Proportional

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(type = "proportional")

Color customization

Change the fill colors

Is is possible to change the fill colors of the streamgraph with scale_fill_manual or an equivalent function.

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

cols <- c("#FFB400", "#FFC740", "#C20008", "#FF020D", "#13AFEF")

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream() +
  scale_fill_manual(values = cols)

The geom_stream function from ggstream

Change the color of the borders

By default the areas have no border but you can add a border color with the color argument of the geom_stream function and modify its width with lwd.

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

cols <- c("#FFB400", "#FFC740", "#C20008", "#FF020D", "#13AFEF")

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(color = 1, lwd = 0.25) +
  scale_fill_manual(values = cols)

Streamplot border color

Change the theme

Note that you can also change the theme to modify the appearance of the chart.

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

cols <- c("#FFB400", "#FFC740", "#C20008", "#FF020D", "#13AFEF")

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(color = 1, lwd = 0.25) +
  scale_fill_manual(values = cols) +
  theme_minimal()

Streamgraph in ggplot2 with ggstream

Advanced arguments

In order to create a streamplot there are underlying non-parametric computations which need a bandwidth (defaults to 0.75) and a grid of values on the X-axis (defaults to 1000). You can change these default values with bw and n_grid.

Note that you can also use an extra range in the estimation with extra_span, that defaults to 0.01 (1%) and specify if the true range of the data should be used on the visualization or the estimation range with true_range.

Bandwidth customization of the stream graph

Bandwidth (bw)

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

cols <- c("#FFB400", "#FFC740", "#C20008", "#FF020D", "#13AFEF")

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(color = 1, lwd = 0.25,
              bw = 1) +
  scale_fill_manual(values = cols) +
  theme_minimal()

X-axis grid in geom_stream with n_grid

Grid (n_grid)

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

cols <- c("#FFB400", "#FFC740", "#C20008", "#FF020D", "#13AFEF")

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(color = 1, lwd = 0.25,
              n_grid = 100) +
  scale_fill_manual(values = cols) +
  theme_minimal()

Extra span and true range of the stream plot in ggplot2

Extra span and true range (extra_span, true_range)

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

cols <- c("#FFB400", "#FFC740", "#C20008", "#FF020D", "#13AFEF")

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(extra_span = 0.2) +
  geom_stream(extra_span = 0.2, true_range = "none",
              alpha = 0.3) +
  scale_fill_manual(values = cols) +
  theme_minimal()

Legend customization

As in other ggplot2 charts you can change the title, the key labels and change the position or remove the legend, as shown in the examples below.

Change the title

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

cols <- c("#FFB400", "#FFC740", "#C20008", "#FF020D", "#13AFEF")

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(extra_span = 0.2) +
  geom_stream(extra_span = 0.2, true_range = "none",
              alpha = 0.3) +
  scale_fill_manual(values = cols) +
  theme_minimal() +
  guides(fill = guide_legend(title = "Title"))

Change the title of the legend of a streamgraph in ggplot2

Change the labels

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

cols <- c("#FFB400", "#FFC740", "#C20008", "#FF020D", "#13AFEF")

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(color = 1, lwd = 0.25) +
  scale_fill_manual(values = cols, labels = LETTERS[1:5]) +
  theme_minimal()

Change the key labels of the legend in ggstream

Remove the legend

# install.packages("ggstream")
library(ggstream)
# install.packages("ggplot2")
library(ggplot2)

cols <- c("#FFB400", "#FFC740", "#C20008", "#FF020D", "#13AFEF")

ggplot(blockbusters, aes(x = year, y = box_office, fill = genre)) +
  geom_stream(color = 1, lwd = 0.25) +
  scale_fill_manual(values = cols) +
  theme_minimal() +
  theme(legend.position = "none")

Remove the legend of the ggplot2 streamplot