facet_wrap and scaling point size

Question

In short: I would like to have separate legends for each "panel" of two-panel plot made using `facet_wrap` . Using `facet_wrap(scales="free")` works fine for when I want different axis scales, but not for the size of points. Background: I have data for several samples with three measurements each: x, y, and z. Each sample is from either class 1 or class 2. x and y have the same distributions in each class. However, all the z measurements for class 1 are less than 1.0; z measurements for class 2 range from 0 to 100. Where I'm stuck: Plot x and y on the x and y axes, respectively. Make the area of each point proportional to its z value. ``` d = matrix(c(runif(100),runif(20)*100),ncol=3) e = data.frame( gl(2,20), d ) colnames(e) = c("class","x","y","z") ggplot( data = e, aes(x=x, y=y, size=z) ) + geom_point() + scale_area() + facet_wrap( ~ class, ncol=1, scales="free" ) ``` Problem: Note that the dots on the first panel are difficult to see because they are on the very low end of the sca…

Accepted Answer

A solution using `grid.arrange`. I've left in the call to `facet_wrap` so the `strip.text` remains. You could easily remove this.

```
# plot for class 1
c1 <- ggplot(e[e$class==1,], aes(x=x,y=y,size=z)) + geom_point() + scale_area() + facet_wrap(~class)
# plot for class 2
c2 <- c1 %+% e[e$class==2,]

library(gridExtra)

grid.arrange(c1,c2, ncol=1)
```

facet_wrap and scaling point size

Solution

Problem