Create a Scatter Plot with Multiple Groups using ggplot2 in R

In this article, we will discuss how to create a scatter plot with multiple groups in R Programming Language.

Geoms can be added to the plot to compute various graphical representations of the data in the plot (points, lines, bars). The geom_point() method is used to create scatter plots in R. The geoms may also be specified with the additional mappings, like color to differently color the points pertaining to different groups. 

geom_point(aes(color = ))

library("ggplot2")


# creating a data frame
df < - data.frame(col1=sample(rep(c(1: 5), each=3)),
                  col2=5: 19)
print("original dataframe")
print(df)

# plotting the data
ggplot(df, aes(x=col1, y=col2)) +
geom_point(aes(color=factor(col1)))

Output

[1] "original dataframe" 
col1 col2 
1     2    5 
2     3    6 
3     4    7 
4     2    8 
5     4    9 
6     1   10 
7     3   11 
8     5   12 
9     5   13 
10    5   14 
11    4   15 
12    1   16 
13    3   17 
14    2   18 
15    1   19

Explanation: The groups are created according to the differences in values of col1. All the circles, for example, belonging to col1=1 are given the red color. This is also illustrated in the index of the plot. 

The following code snippet indicates the method where one of the data frame columns is a non-integral one : 

library("ggplot2")

# creating a data frame
df < - data.frame(col1=sample(rep(c(1: 5), each=3)),
                  col2=letters[5:19])

print("original dataframe")
print(df)

# plotting the data
ggplot(df, aes(x=col1, y=col2)) +
geom_point(aes(color=factor(col1)))

Output

[1] "original dataframe" 
col1 col2 
1     2    e 
2     2    f 
3     4    g 
4     3    h 
5     5    i 
6     1    j 
7     5    k 
8     4    l 
9     1    m 
10    2    n 
11    1    o 
12    3    p 
13    5    q 
14    3    r 
15    4    s