Control Point Border Thickness of ggplot2 Scatterplot in R

In this article, we will see how to control Point Border Thickness of ggplot ScatterPlot in R Programming Language. For this, we will be using geom_point() function. Following is brief information about ggplot function, geom_point().

Syntax : geom_point(size, color, fill, shape, stroke)

Parameter :

• size : Size of Points
• color : Color of Points/Border
• fill : Color of Points
• shape : Shape of Points in in range from 0 to 25
• stroke : Thickness of point border

Return : It creates scatterplots. 

Let us first create a scatterplot with no modification so that the difference is apparent.

Example: 

R

# Load package
library("ggplot2")

# Create data for plotting
data <- data.frame(x = rnorm(10), y = rnorm(10))

# Create Scatterplot with size 10 and green color
ggplot(data, aes(x, y)) +
  geom_point(size = 10, color = "green")

Output:

Scatterplot using ggplot2

To change the shape of the points in scatterplot i.e to make borders around points in Scatterplot, we use shape parameter of geom_point() function to set the value as 21 which specify the shape of points in range from 0 to 25. The following image represents the shape of points with range. Other than that we use fill parameter to fill the color of points and color parameter of border color. 

Shapes of Points of Scatterplot with Range

Example:

R

# Load package
library("ggplot2")

# Create data for plotting
data <- data.frame(x = rnorm(10), y = rnorm(10))

# Create a border around points
# in Scatterplot
ggplot(data, aes(x, y)) +
  geom_point(size = 10, color = "black",
             fill = "green", shape = 21)

Output:

Scatterplot with borders around points

Now to change the thickness of border, we simply use a parameter inside geom_point() function called stroke, which specify the thickness of the border of points in Scatterplot. 

Example:

R

# Load package
library("ggplot2")

# Create data for plotting
data <- data.frame(x = rnorm(10), y = rnorm(10))

# Change thickness of the border
ggplot(data, aes(x, y)) +
  geom_point(size = 10, color = "black",
             fill = "green", shape = 21,
             stroke = 4)

Output:

Scatterplot with changed border thickness of points