[R] Gradient color to a line graph

Jeff Newmiller jdnewmil at dcn.davis.ca.us
Sat Feb 4 21:57:18 CET 2017

You haven't indicated what information you want to convey with this gradient. 

You also are using arrays where you should be using vectors, usually stored in a data frame.

Here is one way using the contributed package ggplot2:

DF <- data.frame( V1=1:10, V2=11:20, C=21:30 )
p <- ggplot( DF, aes( x=V1, y=V2, colour=C ) ) +
    geom_line( size=2 ) +
    scale_colour_gradient( low="red", high="blue" )
print( p )

Sent from my phone. Please excuse my brevity.

On February 4, 2017 12:19:14 PM PST, David Winsemius <dwinsemius at comcast.net> wrote:
>> On Feb 4, 2017, at 9:14 AM, Riyas MJ <riyasmjgeo at gmail.com> wrote:
>> Hi all,
>> I am a new user of R. I just did my first real program.
>> I would like to know how to put a gradient (like rainbow() or
>> etc) to a* line* graph.
>> Example:
>> ar1=array(data=1:10,dim=9)
>> ar2=array(data=11:20,dim=9)
>> plot(ar1,ar2,type="l",col="red",lwd=3)
>> Instead of a red color, I would like to make it in rainbow colors.
>> Tried to do my own and tried searching but everywhere its about
>> gradient to point graph, not to a line graph. Please help, it is
>needed for
>Install the plotrix package and look in its Index page for a function
>name that has both `color` and `line` in its name.

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