How to get multiple ggplot2 scale_fill_gradientn with same scale?

Question

library(ggplot2)
library(cumplyr)
library(scales)
library(RColorBrewer)


myPalette <- colorRampPalette(rev(brewer.pal(11, \"Spectral\")))

x   = 1:5
y   = 1:5
pt         


        

Answer 1

In scale_fill_gradientn set the limits to be the same, so for example:

scale_fill_gradientn(colours = myPalette(4),limits=c(0,4))

And this is p1 and p2:

Answer 2

Use limit in scale_gradientn:

p1 <- ggplot(as.data.frame(d1))
p1 <- p1 + geom_tile(aes(x = x, y = y, fill = val))

p2 <- ggplot(as.data.frame(d2), aes(x = x, y = y, fill = val))
p2 <- p2 + geom_tile(aes(x = x, y = y, fill = val)) 
library(gridExtra)

p1 <- p1 + scale_fill_gradientn(colours = myPalette(4), limits=c(0,4))
p2 <- p2 + scale_fill_gradientn(colours = myPalette(4), limits=c(0,4))
grid.arrange(p1, p2)

The grid.arrange stuff is just to avoid me having to copy/paste two pictures.