The perils of aligning plots in ggplot

Question

QUESTION

How do you combine separate plots (ggplot2), with different y-axis and different plot heights, yet retain alignment?

DETAI

Answer 1

In your gtable g, you can set the relative panel heights,

require(gtable)
g1<-ggplotGrob(top)
g2<-ggplotGrob(bottom)
g<-gtable:::rbind_gtable(g1, g2, "first")
panels <- g$layout$t[grep("panel", g$layout$name)]
g$heights[panels] <- unit(c(1,2), "null")

grid.newpage()
grid.draw(g)