Ggplot - (aes|aesthetic) (plot parameter definition)

Aesthetic are plots parameters that are given by the data.

For parameters that are not related to the data, see Ggplot - Theme

Such as:

• coordinate x and y.
• Color:
  • color: the bar outline,
  • fill: interior colouring
  • alpha
• group - How the data are grouped (Default to the discrete value of the plot)
• weight - The variable to be summed.
• shape - It will use another shape for each point
• size
• stroke

The aes function maps aesthetic to data frame variable.

mapping = aes(x=carat, y=price)

The aes function (map|set):

• the variable carat to x
• and the variable price to y.

Mappings usually stay the same on a plot, so they are stored as defaults

# The carat variable will be x and the prices will be y 
p <- ggplot(diamonds, aes(x=carat,y=price))
 
# This code will map the colour to the green variable
p + geom_point(aes(colour = "green"))
 
# This code will show the colour green for all geoms
p + geom_point(colour = "green")

ggplot(diamonds, aes(x=carat, y=price))
+ geom_point(aes(colour = carat))

• fill. To slice an histogram, area with colour.

ggplot(diamonds, aes(x=price))
+geom_histogram(aes(fill = clarity))