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I am doing a simple scatterplot in R and when I try to use the colorbrewer palette "RdBu" I am getting something clearly different and I have no idea why.

Here is a summary of my data

> summary(d$Year)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
   1880    1914    1947    1947    1980    2014 

> summary(d$NHem)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
-52.000 -21.500  -2.000   3.326  16.000  91.000 

> summary(d$NHem.bin)
-3 -2 -1  0  1  2  3  4  5 
 1 23 28 37 22  4  8 11  1

when I use the command

ggplot(d, aes(x=Year, y=NHem, colour=NHem.bin)) + geom_point() + scale_fill_brewer(palette = "RdBu")

i get this

enter image description here

So that's clearly not "RdBu". What am I doing wrong??

Also, I am creating a bin var so that I can try to maintain the same gradient across 3 separate plots.

Since I am already here, how do I reverse the scale so that the blue end corresponds to the more negative numbers and red corresponds to more positive?

thx

Max Wen
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  • As a side note for future postings: Please read (1) [how do I ask a good question](http://stackoverflow.com/help/how-to-ask), (2) [How to create a MCVE](http://stackoverflow.com/help/mcve) as well as (3) [how to provide a minimal reproducible example in R](http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example#answer-5963610) to get the most out of SO. – lukeA Jun 17 '16 at 07:32

1 Answers1

5

First, you got no fill aesthetics mapped. Second, you should either map a color aesthetic instead or specify a point shape that has a fill: 

library(ggplot2)
ggplot(mtcars, aes(wt, mpg, colour = factor(cyl))) +  
  geom_point() + 
  scale_color_brewer(palette = "RdBu") -> p1

# or
ggplot(mtcars, aes(wt, mpg, fill = factor(cyl))) +  
  geom_point(shape=21, color=NA) + 
  scale_fill_brewer(palette = "RdBu") -> p2

gridExtra::grid.arrange(p1, p2)

gives

enter image description here

lukeA
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  • Chalk that up to inexperience. thx. can you tell me how you would reverse the scale in your chart so that 8 would be at the red end and 4 at the blue end? – Max Wen Jun 17 '16 at 07:43