Categorical bubble plot for mapping studies

Question

How to create a categorical bubble plot, using GNU R, similar to that used in systematic mapping studies (see below)?

Answer 1

This will get you started by adding the tick marks to your xaxis.

To add the lines, just add a line at each level

ggs <- subset(gg, count > 0)
radius <- sqrt( ggs$count / pi )

# ggs$Var1 <- as.character(ggs$Var1)

# set up your tick marks 
#  (this can all be put into a single line in `axis`, but it's placed separate here to be more readable)
#--------------
# at which values to place the x tick marks
x_at <- seq_along(levels(gg$Var1))
# the string to place at each tick mark
x_labels <-   levels(gg$Var1)


# use xaxt="n" to supress the standard axis ticks 
symbols(ggs$Var1, ggs$Var2, radius, inches=0.30, xlab="Research type", ylab="Research area", xaxt="n")
axis(side=1, at=x_at, labels=x_labels)

text(ggs$Var1, ggs$Var2, ggs$count, cex=0.5)

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also, notice that instead of calling the object grid I called it gg, and then ggs for the subset. grid is a function in R. While it is "allowed" to overwrite the function with an object, it is not recommended and can lead to annoying bugs down the line.