rspider-chart

square radar chart in R

I'd like to plot a square radar chart (not a rhombus) in R. I tried to use the fmsb library, but it appears to be unable to rotate the chart.

#create data
data_t <- as.data.frame(matrix( sample( 2:20 , 4 , replace=T) , ncol=4))
colnames(data_t) <- c("math" , "english" , "biology" , "music")
data_t <- rbind(rep(20,4) , rep(0,4) , data_t)

radarchart(data_t)

enter image description here

Solution

  • Sure it's possible. With rotated labels, because otherwise it's a bit ugly. Note I had to size down the original labels using vlcex = 0.00000001

    library(ggplot2)
library(dplyr)
library(tidyr)
library(fmsb)
install.packages("gridGraphics")
library(gridGraphics)

#create data
data_t <- as.data.frame(matrix( sample( 2:20 , 4 , replace=T) , ncol=4))
colnames(data_t) <- c("math" , "english" , "biology" , "music")
data_t <- rbind(rep(20,4) , rep(0,4) , data_t)

# Create the radar chart
radarchart(data_t, vlcex = 0.00000001) # put vlcex = 0 and remove the customized label code to preserve the original labels

# Customizing labels
labels <- colnames(data_t)
n_labels <- length(labels)
angles <- seq(0, 2 * pi, length.out = n_labels + 1)[-1]  # Calculate angles for labels

# Add rotated labels manually
for (i in seq_along(labels)) {
  text(
    x = 1.2 * sin(angles[i]), # Positioning based on sine for x
    y = 1.2 * cos(angles[i]), # Positioning based on cosine for y
    labels[i],
    srt = 45, # Convert radians to degrees and adjust angle
    adj = 1,
    cex = 0.8
  )
}


grab_grob <- function(){
  grid.echo()
  grid.grab()
}

g <- grab_grob()
grid.newpage()
pushViewport(viewport(angle=-45))
grid.draw(g)

    p