Harvey balls in R

Question

How to create a chart like the following in R?

Some toy data would look like this:

# Data
data <- rep(c(0, 25, 50, 75, 100),6) 
data <-  matrix(data, ncol=3, byrow=TRUE) 
colnames(data) <- paste0("factor_", seq(3))
rownames(data) <- paste0("observation_", seq(10))


#                factor_1 factor_2 factor_3
# observation_1         0       25       50
# observation_2        75      100        0
# observation_3        25       50       75
# observation_4       100        0       25
# observation_5        50       75      100
# observation_6         0       25       50
# observation_7        75      100        0
# observation_8        25       50       75
# observation_9       100        0       25
# observation_10       50       75      100

Thanks.

Answer 1

Here's a quick & dirty solution using base graphics and unicode symbols:

library(extrafont)
# font_import() # ... if you need to
loadfonts()
getPch <- function(x) {
  sapply(x, function(x) {
    switch(as.character(x), 
    "0"=-9675,
    "25"=-9684,
    "50"=-9682,
    "75"=-9685,
    "100"=-9679
  )})
}
par(mar=c(2, 7, 2, 4))
plot(y =rep(1:nrow(data), ncol(data)), 
     x = rep(1:ncol(data), each=nrow(data)), 
     pch = getPch(as.vector(data)), 
     axes = F, xlab = "", ylab = "",
     cex = 3, xlim = c(.5, ncol(data) + .5),
     family = "Arial Unicode MS")
abline(v = 0:ncol(data)+.5)
abline(h = 1:nrow(data) + .5)
mtext(side = 1, at=1:ncol(data), text=colnames(data))
mtext(side = 2, at=1:nrow(data), text=rownames(data), las=2)