ggplot2
allows to easily map a variable to marker
features of a scatterplot. This post
explaines how it works through several examples, with explanation
and code.
Here is the magick of ggplot2: the ability
to map a variable to marker features. Here, the marker
color
depends on its value in the field called
Species
in the input data frame.
Note that the legend is built automatically.
You can map variables to any marker features. For instance, specie is represente below using transparency (left), shape (middle) and size (right).
# Transparency
ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, alpha=Species)) +
geom_point(size=6, color="#69b3a2") +
ggtitle("Transparency") +
theme_ipsum()
# Shape
ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, shape=Species)) +
geom_point(size=6, color="lightblue") +
ggtitle("Shape") +
theme_ipsum()
# Size
ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, size=Petal.Width)) +
geom_point(color="darkred") +
ggtitle("Size") +
theme_ipsum()
Last but not least, note that you can map one or several variables to
one or several features. Here, shape, transparency, size and color all
depends on the marker Species
value.
# load ggplot2
library(ggplot2)
library(hrbrthemes)
# A basic scatterplot with color depending on Species
ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, shape=Species, alpha=Species, size=Species, color=Species)) +
geom_point() +
theme_ipsum()
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