How to merge colour and shape?

Question

My troubles started when I had a variable with more than 6 values because that is the current maximum value for the scale_shape function in ggplot2.

Due to that problem

Answer 1

here is an example:

plot1 <- ggplot(dataf, aes(x=Density, y=Growth, colour=Municipality,
        shape=Municipality))
plot1 <- plot1 + geom_point(size=3)
plot1 <- plot1 + scale_colour_discrete() + 
scale_shape_manual(values=as.numeric(dataf$Shape))
plot1

if you need filled shapes, then replace with

scale_shape_manual(values=c(16, 17, 15, 3, 7, 8)[as.numeric(dataf$Shape)])

the tricks are:

1. use same variable for colour and shape aes (Municipality)
2. use scale_shape_manual and make mapping of breaks (here, Municipality) and value (here, dataf$Shape)
3. you need numeric variable instead of factor for values of scale_shape_manual