[R] How to plot graph with different scale (y axis) on same graph?

[Jim Lemon]

On 04/26/2012 08:02 PM, Manish Gupta wrote:
> Hi,
>
> I have my data in below format.
>
> position         var1            var2
> 2                       .1                 10
> 3                       .29               89
> 12                    .56               100
> 425                 .34                1234
> 6546              .12                 21
> ....                   .....                 .....
> ....                   .....                ......
> ....                   .....                ......
>
> I need to plot a grpah for above with position as x - axis and two variables
> with as line on the same plot. I have 5 million records.  How can i
> implement it efficiently.
>
Hi Manish,
You can plot this with twoord.plot (plotrix):

position<-c(2,3,12,425,6546)
var1<-c(.1,.29,.56,.34,.12)
var2<-c(10,89,100,1234,21)
library(plotrix)
twoord.plot(lx=position,ly=var1,rx=position,ry=var2)

but with 5 million records you will just have a jagged block of color. I 
think ghostwheel's suggestion of reducing the number of points is very 
sensible.

Jim