Table of Contents
Label Points on a Scatterplot in R is a way of adding text labels to the data points in a scatterplot. This can be done in R using the text() function, which takes the x, y and label parameters to specify the coordinates of the point and the corresponding label. This is useful for providing additional context to the data points in a scatterplot.
This tutorial provides an example of how to label the points on a scatterplot in both base R and ggplot2.
Example 1: Label Scatterplot Points in Base R
To add labels to scatterplot points in base R you can use the text() function, which uses the following syntax:
text(x, y, labels, …)
- x: The x-coordinate of the labels
- y: The y-coordinate of the labels
- labels: The text to use for the labels
The following code shows how to label a single point on a scatterplot in base R:
#create data df <- data.frame(x=c(1, 2, 3, 4, 5, 6), y=c(7, 9, 14, 19, 12, 15), z=c('A', 'B', 'C', 'D', 'E', 'F')) #create scatterplot plot(df$x, df$y) #add label to third point in dataset text(df$x[3], df$y[3]-1, labels=df$z[3])
The following code shows how to label every point on a scatterplot in base R:
#create data df <- data.frame(x=c(1, 2, 3, 4, 5, 6), y=c(7, 9, 14, 19, 12, 15), z=c('A', 'B', 'C', 'D', 'E', 'F')) #create scatterplot plot(df$x, df$y) #add labels to every point text(df$x, df$y-1, labels=df$z)
Example 2: Label Scatterplot Points in ggplot2
The following code shows how to label a single point on a scatterplot in ggplot2:
#load ggplot2 library(ggplot2) #create data df <- data.frame(x=c(1, 2, 3, 4, 5, 6), y=c(7, 9, 14, 19, 12, 15), z=c('A', 'B', 'C', 'D', 'E', 'F')) #create scatterplot with a label on the third point in dataset ggplot(df, aes(x,y)) + geom_point() + annotate('text', x = 3, y = 13.5, label = 'C')
The following code shows how to label every point on a scatterplot in ggplot2:
#load ggplot2 & ggrepel for easy annotations library(ggplot2) library(ggrepel) #create data df <- data.frame(x=c(1, 2, 3, 4, 5, 6), y=c(7, 9, 14, 19, 12, 15), z=c('A', 'B', 'C', 'D', 'E', 'F')) #create scatterplot with a label on every point ggplot(df, aes(x,y)) + geom_point() + geom_text_repel(aes(label = z))
