R help - Jul 2008 - fill in area between 2 lines with a color

Hi - I'd like to have the area between 2 lines on a x-y plot be filled with
grey, but I haven't had
any luck using polygon or rect.  (In reality, I'd like to do this for twice
- once for a low group and once for a high group - and then I'd like to plot
a set of data points for a 'normal' group together with these 2 grey
areas.)

Here's a simple example of the 2 lines:
     
age=1:10
y.low=rnorm(length(age),150,25)+10*age
y.high=rnorm(length(age),250,25)+10*age
plot(age,y.high,type='n',ylim=c(100,400),ylab='Y
Range',xlab='Age (years)')
lines(age,y.low,col='grey')
lines(age,y.high,col='grey')

Is it possible to fill the area between the 2 lines filled with, for
example, 'grey30' ?

thanks very much in advance,
David Freedman

-----
David Freedman
Atlanta
-- 
View this message in context:
http://www.nabble.com/fill-in-area-between-2-lines-with-a-color-tp18556096p18556096.html
Sent from the R help mailing list archive at Nabble.com.

try the following:

age <- 1:10
y.low <- rnorm(length(age), 150, 25) + 10*age
y.high <- rnorm(length(age), 250, 25) + 10*age

plot(age,y.high,type = 'n', ylim = c(100, 400),
     ylab = 'Y Range', xlab = 'Age (years)')
lines(age, y.low, col = 'grey')
lines(age, y.high, col = 'grey')

polygon(c(age, rev(age)), c(y.high, rev(y.low)),
     col = "grey30", border = NA)


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
      http://perswww.kuleuven.be/dimitris_rizopoulos/


Quoting David Freedman <3.14david at gmail.com>:
>
> Hi - I'd like to have the area between 2 lines on a x-y plot be filled
with
> grey, but I haven't had
> any luck using polygon or rect.  (In reality, I'd like to do this for
twice
> - once for a low group and once for a high group - and then I'd like to
plot
> a set of data points for a 'normal' group together with these 2
grey areas.)
>
> Here's a simple example of the 2 lines:
>
> age=1:10
> y.low=rnorm(length(age),150,25)+10*age
> y.high=rnorm(length(age),250,25)+10*age
> plot(age,y.high,type='n',ylim=c(100,400),ylab='Y
Range',xlab='Age (years)')
> lines(age,y.low,col='grey')
> lines(age,y.high,col='grey')
>
> Is it possible to fill the area between the 2 lines filled with, for
> example, 'grey30' ?
>
> thanks very much in advance,
> David Freedman
>
> -----
> David Freedman
> Atlanta
> --
> View this message in context:   
>
http://www.nabble.com/fill-in-area-between-2-lines-with-a-color-tp18556096p18556096.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>


Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

on 07/20/2008 11:34 AM David Freedman wrote:
> Hi - I'd like to have the area between 2 lines on a x-y plot be filled
with
> grey, but I haven't had
> any luck using polygon or rect.  (In reality, I'd like to do this for
twice
> - once for a low group and once for a high group - and then I'd like to
plot
> a set of data points for a 'normal' group together with these 2
grey areas.)
> 
> Here's a simple example of the 2 lines:
>      
> age=1:10
> y.low=rnorm(length(age),150,25)+10*age
> y.high=rnorm(length(age),250,25)+10*age
> plot(age,y.high,type='n',ylim=c(100,400),ylab='Y
Range',xlab='Age (years)')
> lines(age,y.low,col='grey')
> lines(age,y.high,col='grey')
> 
> Is it possible to fill the area between the 2 lines filled with, for
> example, 'grey30' ?
> 
> thanks very much in advance,
> David Freedman
Try this:


age=1:10

y.low=rnorm(length(age),150,25)+10*age

y.high=rnorm(length(age),250,25)+10*age

plot(age,y.high,type='n',ylim=c(100,400),ylab='Y Range',
      xlab='Age (years)')

lines(age,y.low,col='grey')
lines(age,y.high,col='grey')


polygon(c(age, rev(age), age[1]), c(y.low, rev(y.high), y.low[1]),
         col = "grey30")


What you essentially need to do is to 'walk' the boundary of the 
polygon, be sure to 'close' the open end by returning to the starting 
point, and then fill it.

HTH,

Marc Schwartz