Home/ Questions/Q 6571347
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-25T14:52:14+00:00

I produced biplot with this R code: set.seed(12345) require(ggplot2) AData <- data.frame(Glabel=LETTERS[1:7], A=rnorm(7, mean

  • 0

I produced biplot with this R code:

set.seed(12345)
require(ggplot2)
AData <- data.frame(Glabel=LETTERS[1:7], A=rnorm(7, mean = 0, sd = 1), B=rnorm(7, mean = 0, sd = 1))
TData <- data.frame(Tlabel=LETTERS[11:20], A=rnorm(10, mean = 0, sd = 1), B=rnorm(10, mean = 0, sd = 1))
i <- 2
j <- 3
p <- ggplot(data=AData, aes(AData[, i], AData[, j])) + geom_point() + theme_bw()
p <- p + geom_text(aes(data=AData, label=Glabel), size=3, vjust=1.25, colour="black")
p <- p + geom_segment(data = TData, aes(xend = TData[ ,i], yend=TData[ ,j]),
              x=0, y=0, colour="black",
              arrow=arrow(angle=25, length=unit(0.25, "cm")))
p <- p + geom_text(data=TData, aes(x=TData[ ,i], y=TData[ ,j], label=Tlabel), size=3, vjust=1.35, colour="black")

Output
enter image description here

Everything is fine except the arrows labels. I’d like to have the labels at the end of the arrows and in the same direction as arrows. Any idea and/or solution. Thanks in advance.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Two possibilities:

    p <- p + geom_text(data=TData, aes(x=1.2*TData[ ,i], 
                                   y=1.2*TData[ ,j], 
                  label=Tlabel), size=3, vjust=0, colour="black")
p
#-----------------------------------
p <- p + geom_text(data=TData, aes(x=TData[ ,i] +.1*sign(TData[ ,i]), 
                                   y=TData[ ,j]+.1*sign(TData[ ,j]), 
                  label=Tlabel), size=3, vjust=0, colour="black")
p

    First one leaves labels away from the arrows a distance that varies with the “strengths” while the second one a fixed distance on the graphics plotting scale (probably the preferred solution and the one illustrated below).

    Second version as image

    And finally a fully “trigonometricized “version that will get the labels exactly in the same vector as the arrows. (The sameness of the sign(.) argument is a result of the conventions for arctangent values. Ya do what ya gatta do.) :

    p <- ggplot(data=AData, aes(AData[, i], AData[, j])) + geom_point() + theme_bw()
p <- p + geom_text(aes(data=AData, label=Glabel), size=3, vjust=1.25, colour="black")
p <- p + geom_segment(data = TData, aes(xend = TData[ ,i], yend=TData[ ,j]),
              x=0, y=0, colour="black",
              arrow=arrow(angle=25, length=unit(0.25, "cm")))
p <- p + geom_text(data=TData, 
            aes(x=TData[ ,i] +.1*cos(atan(TData[ ,j]/TData[ ,i]))*sign(TData[ ,i]), 
                y=TData[ ,j] +.1*sin(atan(TData[ ,j]/TData[ ,i]))*sign(TData[ ,i]), 
            label=Tlabel), size=3, vjust=0, colour="red")
    • 0