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points() colored by value

3 messages · Chris82, michael.weylandt at gmail.com (R. Michael Weylandt, Sarah Goslee

Chris82
# 
Hi R users,

I want to colored points by their value

for example:

x <- c(1,2,3,4)
y <- c(1,2,3,4)
z <- c(2,3,4,9)

y and x are coordinates

z is the value of the coordinates

points(x,y,col= rainbow(z))

something like that

But haven't found any solution at the moment.

Thanks.

Chris



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michael.weylandt at gmail.com (R. Michael Weylandt
# 
Try either col=z or col=rainbow(max(z))[z] depending on what color scheme you want. 

Michael
On Nov 15, 2011, at 1:47 PM, Chris82 <rubenbauar at gmx.de> wrote:

            

      
      
      
    

        

      
      
    

  
  


  


      

    

    

      
      

        


  

        

      Sarah Goslee
    

    

      
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Hi Chris,

        
On Tue, Nov 15, 2011 at 1:47 PM, Chris82 <rubenbauar at gmx.de> wrote:

            

      
      
      
    

        
In the general sense:
plot(x, y, col=rainbow(length(unique(z)))[as.factor(z)])

converting z to a factor to use as an index is just a quick way to
convert z to sequential values 1,2,3,4 rather than 2,3,4,9 and to
ensure that multiple and unsorted values use the correct color. If z
contains only sequential values, that bit is unnecessary.

I like RColorBrewer for things like this, rather than rainbow, but it
depends on what you're trying to do.

Sarah