R ggplot heatmap using geom_tile(): how to sort by year and show all years in y-axis?

Question

After studying Hadley\'s book and searching here on SO I have created a heatmap consisting of a matrix of years and months, with the colour varying according the percentage chan

Answer 1

For the first two points, you can replace scale_y_continuous with scale_y_reverse to have the earliest years on top, and explicitly specify the breaks and labels.

p_heat +  scale_y_reverse(breaks=1995:2011, labels=1995:2011, expand=c(0,0) )