[R Course] Data Visualisation with R: Options

Learn how to use the multitude options included in the ggplot2 package such as themes, scales, axes, legends, and facetting.

Set up

We will work with data from UNIDO and US data from map_data.

Data

You can load UNIDO data stored in a Gsheet by using the following code!

library(gsheet)

dataGraph <- gsheet2tbl("https://docs.google.com/spreadsheets/d/1uLaXke-KPN28-ESPPoihk8TiXVWp5xuNGHW7w7yqLCc/edit?usp=sharing")

We want to create a column with random data from a sample of 1 to 500.

dataGraph$sample <- sample(1:500, 18, replace=F)

You can load US data from map_data by using the following code!

library(ggmap)

usa <- map_data("usa")

Package

For the examples to work, we need to load the ggplot2 package.

library(ggplot2)

Themes

Themes control the display of all non-data elements of the plot. You can override all settings with a complete theme like theme_bw(), or choose to tweak individual settings by using theme() and the element_ functions. Use theme_set() to modify the active theme, affecting all future plots.

Default

The default themes:

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_grey()

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_gray()

BW

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_bw()

Linedraw

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_linedraw()

Light

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_light()

Dark

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_dark()

Minimal

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_minimal()

Classic

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_classic()

Void

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_void()

Economist

library(ggthemes)

ggplot(usa, aes(x = long, y = lat, group = group)) +
  geom_polygon() +
  theme_economist()

Adding the scale_color_economist() function to color points with the economist theme colors.

ggplot(dataGraph, aes(date, GDP, color = country)) + 
  geom_point() + 
  theme_economist() + 
  scale_color_economist()

Stata

ggplot(dataGraph, aes(date, GDP, color = country)) + 
  geom_point() + 
  theme_stata() + 
  scale_color_stata()

Wall Street Journal

ggplot(dataGraph, aes(date, GDP, color = country)) + 
  geom_point() + 
  theme_wsj() + 
  scale_colour_wsj("colors6")

LibreOffice Calc

ggplot(dataGraph, aes(date, GDP, color = country)) + 
  geom_point() + 
  theme_calc() + 
  scale_colour_calc()

Modify components of a theme

Labs

Title, subtitle, x, y, coulour, shape, caption and tag

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries",
       subtitle = "(2010 - 2015)",
       x = "Years",
       y = "Gross domestic product",
       colour = "Countries",
       shape = "Sections", 
       caption = "Source: Nüance-R", 
       tag = "A")

Theme

Plot

Title

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(plot.title = element_text(size = 20))

Background

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(plot.title = element_text(size = 20), 
        plot.background = element_rect(fill = "gold"))

Legend

Position

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  theme(legend.position = "none")

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  theme(legend.position = "bottom")

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(legend.position = "left")

Justification, Box, Margin

# Or place legends inside the plot using relative coordinates between 0 and 1
# legend.justification sets the corner that the position refers to
ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(legend.position = c(.95, .95),
        legend.justification = c("right", "top"),
        legend.box.just = "right",
        legend.margin = margin(6, 6, 6, 6))

Box background and margin

# The legend.box properties work similarly for the space around all the legends
ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(legend.box.background = element_rect(),
        legend.box.margin = margin(6, 6, 6, 6))

Key

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(legend.key = element_rect(fill = "white", colour = "black"))

Text and Title

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(legend.text = element_text(size = 8, colour = "red"),
        legend.title = element_text(face = "bold"))

Axis

Line

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") +
  theme(axis.line = element_line(size = 3, colour = "grey80"))

Text

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") +
  theme(axis.line = element_line(size = 3, colour = "grey80"),
        axis.text = element_text(colour = "blue"),
        axis.text.x = element_text(margin = margin(t = .8, unit = "cm"), angle = 90))

Ticks

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") +
  theme(axis.line = element_line(size = 3, colour = "grey80"),
        axis.text = element_text(colour = "blue"),
        axis.text.x = element_text(margin = margin(t = .8, unit = "cm"), angle = 90),
        axis.ticks = element_line(size = 2),
        axis.ticks.length.y = unit(.25, "cm"),
        axis.ticks.length.x = unit(.3, "cm"),
        axis.title.y = element_text(size = 15, angle = 90))

Panel

Background

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(plot.title = element_text(size = 20), 
        panel.background = element_rect(fill = "lavender", colour = "purple"))

Border

• Default

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") +
  theme(plot.title = element_text(size = 20), 
        panel.border = element_rect(fill = NA))

• Linetype option

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") +
  theme(plot.title = element_text(size = 20), 
        panel.border = element_rect(linetype = "dashed", fill = NA))

Grid major and minor

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(plot.title = element_text(size = 20), 
        panel.grid.major = element_line(colour = "magenta"))

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(panel.grid.major.y = element_blank(),
        panel.grid.minor.y = element_blank())

ggplot(dataGraph, aes(date, GDP)) +
  geom_point(aes(colour = country, shape = section), size = 3) +
  labs(title = "Gross Domestic Product by Countries") + 
  theme(panel.grid.major.x = element_blank(),
        panel.grid.minor.x = element_blank())

Strip

Background

ggplot(dataGraph, aes(sample, GDP)) +
  geom_point() +
  facet_wrap(~ country) +
  theme(strip.background = element_rect(colour = "black", fill = "white"))

Text

ggplot(dataGraph, aes(sample, GDP)) +
  geom_point() +
  facet_wrap(~ country) +
  theme(strip.text.x = element_text(colour = "white", face = "bold"))

ggplot(dataGraph, aes(sample, GDP)) +
  geom_point() +
  facet_wrap(~ country) +
  theme(panel.spacing = unit(2, "lines"))

Facetting

Facet wrap

ggplot(dataGraph, aes(sample, GDP)) +
  geom_point() +
  facet_wrap(~ country)

Facet Grid

Rows

ggplot(dataGraph, aes(GDP, sample)) + 
  geom_point() + 
  facet_grid(rows = vars(country))

Cols

ggplot(dataGraph, aes(GDP, sample)) + 
  geom_point() + 
  facet_grid(cols = vars(country))

Vars

ggplot(dataGraph, aes(GDP, sample)) + 
  geom_point() + 
  facet_grid(vars(country), vars(section)) + 
  theme(axis.text.x = element_text(angle = 90))

# You can also choose whether the scales should be constant across all panels (the default), 
# or whether they should be allowed to vary
ggplot(dataGraph, aes(GDP, sample, colour = country)) +
  geom_point() + 
  facet_grid(. ~ country, scales = "free") + 
  theme(axis.text.x = element_text(angle = 90))

Guides

Fill

ggplot(dataGraph, aes(date, GDP, fill=country)) + 
  geom_bar(stat="identity", position = "dodge") + 
  guides(fill = guide_legend(title = "LEFT", 
                             title.position = "left",
                             title.theme = element_text(size = 15, face = "italic", colour = "red",angle = 0)))

Colour

ggplot(dataGraph, aes(date, GDP, colour=country)) +
  geom_jitter(alpha = 1/3, width = 0.01, height = 0.01) + 
  guides(colour = guide_legend(override.aes = list(alpha = 1)))

Scales

Sequential, diverging and qualitative

The brewer scales provides sequential, diverging and qualitative colour schemes from ColorBrewer. These are particularly well suited to display discrete values on a map. See the colorbrewer2 website for more information.

Default

ggplot(iris, aes(Sepal.Length, Sepal.Width)) + 
        geom_point(aes(colour = Species))

Scale colour brewer

ggplot(iris, aes(Sepal.Length, Sepal.Width)) + 
  geom_point(aes(colour = Species)) + 
  scale_colour_brewer("Type of\nSpecies")

ggplot(iris, aes(Sepal.Length, Sepal.Width)) + 
  geom_point(aes(colour = Species)) +
  scale_colour_brewer(palette = "Greens")

ggplot(iris, aes(Sepal.Length, Sepal.Width)) + 
  geom_point(aes(colour = Species)) +
  scale_colour_brewer(palette = "Set1")

Scale fill brewer

# scale_fill_brewer works just the same as
# scale_colour_brewer but for the fill option
ggplot(dataGraph, aes(date, GDP, fill = country)) +
  geom_bar(stat = "identity", position = "dodge") + 
  scale_fill_brewer()

ggplot(dataGraph, aes(date, GDP, fill = country)) +
  geom_bar(stat = "identity", position = "dodge") +
  scale_fill_brewer(direction = -1)

Viridis colour

The viridis scales provide colour maps that are perceptually uniform in both colour and black-and-white. They are also designed to be perceived by viewers with common forms of colour blindness. See also https://bids.github.io/colormap/.

Ordered factors

# viridis is the default colour/fill scale for ordered factors
dataGraph$section <- factor(dataGraph$section, levels=c("a", "b", "c", "d", "e", "f"), ordered=TRUE)

ggplot(dataGraph, aes(GDP, sample)) +
  geom_point(aes(colour = section))

Discrete data: Colour

Viridis

# Use viridis_d with discrete data
# Change scale label
ggplot(dataGraph, aes(GDP, sample)) +
  geom_point(aes(colour = country)) + 
  scale_colour_viridis_d("Countries")

Plasma

# Option plasma
ggplot(dataGraph, aes(GDP, sample)) +
  geom_point(aes(colour = country)) + 
  scale_colour_viridis_d(option = "plasma")

Inferno

# Option inferno
ggplot(dataGraph, aes(GDP, sample)) +
  geom_point(aes(colour = country)) + 
  scale_colour_viridis_d(option = "inferno")

Discrete data: Fill

Viridis

ggplot(dataGraph, aes(date, GDP, fill = country)) + 
  geom_bar(stat = "identity", position = "dodge") + 
  scale_fill_viridis_d()

Direction

ggplot(dataGraph, aes(date, GDP, fill = country)) + 
  geom_bar(stat = "identity", position = "dodge") + 
  scale_fill_viridis_d(direction = -1)

Magma

ggplot(dataGraph, aes(date, GDP, fill = country)) + 
  geom_bar(stat = "identity", position = "dodge") + 
  scale_fill_viridis_d(option = "magma")

Cividis

ggplot(dataGraph, aes(date, GDP, fill = country)) + 
  geom_bar(stat = "identity", position = "dodge") + 
  scale_fill_viridis_d(option = "cividis")

Line patterns

Default line types based on a set supplied by Richard Pearson, University of Manchester. Continuous values can not be mapped to line types.

Aes linetype

ggplot(dataGraph, aes(date, GDP)) + 
  geom_line(aes(group = country, linetype = country))

Colored line type

ggplot(dataGraph, aes(date, GDP, colour = country)) + 
  geom_line(aes(group = country, linetype = country))

Common line types

Shapes

scale_shape maps discrete variables to six easily discernible shapes (aka glyphs). If you have more than six levels, you will get a warning message, and the seventh and subsequence levels will not appear on the plot. Use scale_shape_manual() to supply your own values. You can not map a continuous variable to shape.

Shape

ggplot(dataGraph, aes(GDP, sample)) + 
  geom_point(aes(shape = country))

Solid

ggplot(dataGraph, aes(GDP, sample)) + 
  geom_point(aes(shape = country)) + 
  scale_shape(solid = FALSE)

Legend

# Change the name of the legend
ggplot(dataGraph, aes(GDP, sample)) + 
  geom_point(aes(shape = country)) +
  scale_shape(name = "Countries")

Coloured shapes

ggplot(dataGraph, aes(GDP, sample)) + 
  geom_point(aes(shape = country, colour = country)) +
  scale_shape(name = "Countries")

ggplot(dataGraph, aes(date, GDP, colour = country)) + 
  geom_line(aes(group = country, linetype = country)) + 
  geom_point(aes(colour = country, shape = country))

Size

• Fixed size

ggplot(dataGraph, aes(GDP, sample)) + 
  geom_point(aes(shape = country, colour = country), size = 5)

ggplot(dataGraph, aes(date, GDP, colour = country)) + 
  geom_line(aes(group = country, linetype = country)) + 
  geom_point(aes(colour = country, shape = country), size = 3)

• Aes size

ggplot(dataGraph, aes(GDP, sample)) + 
  geom_point(aes(shape = country, colour = country, size = GDP))

ggplot(dataGraph, aes(date, GDP, colour = country)) + 
  geom_line(aes(group = country, linetype = country)) + 
  geom_point(aes(colour = country, shape = country, size = GDP))

List of all shapes

df_shapes <- data.frame(shape = 0:24)
ggplot(df_shapes, aes(0, 0, shape = shape)) +
  geom_point(aes(shape = shape), size = 5, fill = 'red') +
  scale_shape_identity() +
  facet_wrap(~shape) +
  theme_void()