[R] Plotting problems directional or rose plots

[alanm (Alan Mitchell)]

I'm not sure if there are any packages that do this, but I've created similar plots in R.  The easiest way I've found is to think in terms of a unit circle in polar coordinates for drawing the plot.  
I haven't tested the code below, but it will give you the idea.


dist=dist/9000

t = seq(0,360,length.out=1000)*pi/180  #want radians not degrees

angle=angle*pi/180

circle$x=cos(t)
circle$y=sin(t)

plot(circle$x,circle$y,type='l')

You can use the polygon function to draw the 'petals'.

# for 0-10

t0 = seq(0,10,length.out=50)*pi/180

petal0$x = dist[1]*cos(t0)
petal0$y = dist[1]*sin(t0)

polygon( x=c(0,petal0$x,0),y=c(0,petal0$y,0),col=color.list[1])


I hope this helps.  

Alan Mitchell





-----Original Message-----
From: kitty [mailto:kitty.a1000 at gmail.com]
Sent: Tue 7/26/2011 2:20 PM
To: r-help at r-project.org
Subject: [R] Plotting problems directional or rose plots
 
Hi,

I'm trying to get a plot that looks somewhat like the attached image
(sketched in word).
I think I need somthing called a rose diagram? but I can't get it to do what
I want. I'm happy to use any library.

Essentially, I want a circle with degree slices every 10 degrees with 0 at
the top representing north, and
'tick marks' around the outside in 10 degree increments to match the slices
(so the slices need to be ofset by 5 degrees so the 0 degree slice actually
faces north)
I then want to be able to colour in the slices depending on the distance
that the factor extends to; so for example the 9000 dist is the largest in
the example so should fill the slice,
a distance in this plot of 4500 would fill halfway up the slice.
I also want to be able to specify the colour of each slice so that I can
relate it back to the spatial correlograms I have.

I have added some sample data below.

Thank you for reading my post,
All help is greatly appreciated,
K

sample data:

#distance factor extends to
dist<-c(5000,7000,9000,4500,6000,500)

#direction
angle<-c(0,10,20,30,40,50)

#list of desired colour example, order corrisponds to associated
angle/direction
color.list<-c('red','blue','green','yellow','pink','black')

(my real data is from 0 to 350 degrees, and so I have corresponding distance
and colour data for each 10 degree increment).