CODEWITHSUNDEEP
rggplot2
user1322296
user1322296

Reputation: 566

match fill gradient across different plots

lets say I have this data:

d1 <- data.frame(x = letters[1:3], y=LETTERS[24:26], num = 1:3)
d2 <- data.frame(x = letters[1:3], y=LETTERS[24:26], num = c(1,2,30))

library(gridExtra)
library(ggplot2) 

ggd1 <- ggplot(d1, aes(x=x,y=y)) + 
          geom_tile(aes(fill=num)) + 
          scale_fill_gradient(low = "green", high = "blue")
ggd2 <- ggplot(d2, aes(x=x,y=y)) + 
          geom_tile(aes(fill=num)) + 
          scale_fill_gradient(low = "green", high = "blue")

grid.arrange(ggd1,ggd2)

enter image description here

My question is how can I standardise the fill gradient so that even though the extent of the data in d1 and d2 differ, colours for X-a,Y-b shoud match for both plots but Z-c should differ by an order of magnitude. i.e. I want to keep the same scale for both plots.

Upvotes: 2

Views: 1962

Answers (2)

Henrik
Henrik

Reputation: 67788

If you wish the scale of the plots to be the same, it may suffice with one scale. Then, instead of using grid.arrange, you may bind the two data sets together, and add a grouping variable which can be used in facet_wrap:

d3 <- rbind(d1, d2)
d3$grp <- rep(1:2, each = 3)

# You may also create a group variable before binding the df:s together, e.g.
d1$grp <- 1
d2$grp <- 2
rbind(d1, d2)



ggplot(d3, aes(x = x, y = y)) + 
  geom_tile(aes(fill = num)) + 
  scale_fill_gradient(low = "green", high = "blue") +
  facet_wrap(~ grp, ncol = 1)

enter image description here

Upvotes: 4

BrodieG
BrodieG

Reputation: 52677

Add limits to each plot:

ggd1 <- ggplot(d1, aes(x=x,y=y)) + 
  geom_tile(aes(fill=num)) + 
  scale_fill_gradient(low = "green", high = "blue", limits=c(1, 30))
ggd2 <- ggplot(d2, aes(x=x,y=y)) + 
  geom_tile(aes(fill=num)) + 
  scale_fill_gradient(low = "green", high = "blue", limits=c(1, 30))
grid.arrange(ggd1,ggd2)

enter image description here

Upvotes: 7

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