Color Gradients With ggplot

Question

I have some geographic x,y,z data which I plot as follows

p<-ggplot(aes(x=x,y=y,fill=z),data=my_data)

I then apply a gradient

p<-p + scale_fill_gradient(low = "pink", high = "green")

And then tile and display the data

p<-p + geom_tile()
p

This works and gives the following:

One would think then, that I could replace the scale_fill_gradient() call with any number of other options such as

p<-p + scale_color_hue()
p<-p + scale_colour_gradientn(colours=c("#E5F5F9","#99D8C9","#2CA25F"))
p<-p + scale_colour_gradientn(colours = rainbow(7))
p<-p + scale_colour_brewer() 

would work.

But they don't, all I get is a gradient of blue.

Any thoughts as to why this might be, and how I can generate lots of happy colours?

Solution

There are two versions of these scale functions, one for colour and one for fill. You just needed to use the fill versions, i.e. scale_fill_hue, etc.