[R] 2d plotting and colours

Asha Jayanthi ashajayanthi at hotmail.com
Thu Mar 31 08:36:22 CEST 2005


Thank you.

mycols <- c("brown","orange","tomato")
plot(x,col = mycols[cl$cluster])

this works. I can define distinct colours and check the graph.

the rest of the examples does not give a wide palette to choose from

Asha
>From: "Mulholland, Tom" <Tom.Mulholland at dpi.wa.gov.au>
>To: "Asha Jayanthi" <ashajayanthi at hotmail.com>,<r-help at stat.math.ethz.ch>
>Subject: RE: [R] 2d plotting and colours
>Date: Thu, 31 Mar 2005 10:14:13 +0800
>
>Since I was only concentrating on colour issues and not on your specific 
>problem I was just showing the possibilities.
>
>Does this code help
>
>n <- 5
>par(mfrow = c(2,2))
>palette("default")
>barplot(1:25,col = 1:25)
>palette(rainbow(n))
>barplot(1:25,col = 1:25)
>palette(rgb((0:15)/15, g=0,b=0, names=paste("red",0:15,sep=".")))
>barplot(1:25,col = 1:25)
>
>
>require(cluster)
>x <- runif(100) * 8 + 2
>cl <- kmeans(x, n)
>palette(rainbow(n))
>plot(x, col = cl$cluster)
>abline(h = cl$centers, lty = 2,col = "grey" )
>palette(palette()[order(cl$centers)])
>points(x,col = cl$cluster,pch = 20,cex = 0.4)
>
>However you may wish to choose your colours in a way that is different from 
>cl$cluster which is why I changed the palette before plotting the points. 
>You should see that they now are ordered from bottom to top of the last 
>plot.
>
>You could also choose to create a vector with your colours and then use the 
>value in cl$cluster to select the colours
>
>mycols <- rainbow(n)
>plot(x,col = mycols[cl$cluster])
>
>Tom
>
> > -----Original Message-----
> > From: Asha Jayanthi [mailto:ashajayanthi at hotmail.com]
> > Sent: Thursday, 31 March 2005 9:17 AM
> > To: r-help at stat.math.ethz.ch
> > Subject: RE: [R] 2d plotting and colours
> >
> >
> > Thank you very much.
> >
> > the code
> > plot(x, col = s)
> > points(cl$centers, col = s, pch = 8, cex=2)
> >
> > does not plot the points according to the group colors. The
> > plots are used
> > to identify the groups by colors
> >
> > That could be done by
> >
> > plot(x, col = cl$cluster)
> >
> > This means that we need to set the default colours , say col
> > = cl$cluster =
> > a set of group numbers say 1...10 should produce 10 distinct
> > colours points
> > grouped by colour.
> >
> > how to do this when you have more than 8 group colours to plot
> >
> > >From: "Mulholland, Tom" <Tom.Mulholland at dpi.wa.gov.au>
> > >To: <r-help at stat.math.ethz.ch>,"Asha Jayanthi"
> > <ashajayanthi at hotmail.com>
> > >Subject: RE: [R] 2d plotting and colours
> > >Date: Wed, 30 Mar 2005 15:59:46 +0800
> > >
> > >And getting back to your question about the palette
> > >
> > >there are a lot of ways to do this
> > >
> > >assuming you have just started a session
> > >
> > >palette()
> > ># will give
> > >#[1] "black"   "red"     "green3"  "blue"    "cyan"
> > >#[6] "magenta" "yellow"  "gray"
> > >
> > >palette(rainbow(24))  # There's also 'heat.colors' & 'topo.colors'
> > >palette()
> > >
> > ># [1] "red"         "#FF4000"     "#FF8000"
> > ># [4] "#FFBF00"     "yellow"      "#BFFF00"
> > ># [7] "#80FF00"     "#40FF00"     "green"
> > >#[10] "#00FF40"     "#00FF80"     "#00FFBF"
> > >#[13] "cyan"        "deepskyblue" "#0080FF"
> > >#[16] "#0040FF"     "blue"        "#4000FF"
> > >#[19] "#8000FF"     "#BF00FF"     "magenta"
> > >#[22] "#FF00BF"     "#FF0080"     "#FF0040"
> > >
> > >palette(rgb((0:15)/15, g=0,b=0, names=paste("red",0:15,sep=".")))
> > >palette()
> > ># [1] "black"   "#110000" "#220000" "#330000" "#440000"
> > ># [6] "#550000" "#660000" "#770000" "#880000" "#990000"
> > >#[11] "#AA0000" "#BB0000" "#CC0000" "#DD0000" "red2"
> > >#[16] "red"
> > >
> > >If you are looking to use colours that take account of
> > colour blindness
> > >you could try the package dichromat. (I think 2.1 will have
> > some of this
> > >inbuilt)
> > >
> > >Once you look through the help files associated with some of
> > these options
> > >you
> > >will find the way that best suits your method of working.
> > >
> > >Tom
> > >
> > >
> > >
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: Uwe Ligges [mailto:ligges at statistik.uni-dortmund.de]
> > > > Sent: Wednesday, 30 March 2005 3:18 PM
> > > > To: TEMPL Matthias
> > > > Cc: r-help at stat.math.ethz.ch; Asha Jayanthi
> > > > Subject: Re: [R] 2d plotting and colours
> > > >
> > > >
> > > > TEMPL Matthias wrote:
> > > >
> > > > > Hi!
> > > > >
> > > > > There are more than 8 colors.
> > > >
> > > > Yes, e.g. for rgb space there are 16777216, see ?rgb.
> > > >
> > > > Uwe Ligges
> > > >
> > > >
> > > >
> > > > > x <- rbind(matrix(rnorm(100, sd = 0.3), ncol = 2),
> > > > >                 matrix(rnorm(100, mean = 1, sd = 0.3),
> > ncol = 2))
> > > > >
> > > > > (cl <- kmeans(x, i, 20))
> > > > >
> > > > > s <- c("tomato4", "turquoise", "slateblue", "wheat",
> > > > "snow", "skyblue",
> > > > > "peru", "pink")
> > > > > # see at:
> > > > > colors()
> > > > >
> > > > > plot(x, col = s)
> > > > >
> > > > > points(cl$centers, col = s, pch = 8, cex=2)
> > > > >
> > > > >
> > > > > Best,
> > > > > Matthias
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >>Hi!
> > > > >>
> > > > >>I am new to R just 3 days in it and i apologize if my
> > > > >>questions seem very
> > > > >>trivial and consumed your valuable time.
> > > > >>
> > > > >>I am coding in perl and i stumbled upon R regarding
> > plotting good
> > > > >>statistical graphs.
> > > > >>
> > > > >>I tried the kmean clustering for a large matrix ,say > 150 *
> > > > >>150 . I tried
> > > > >>the example code given in the tutorial to perform 2d plot
> > > > >>
> > > > >># i ranges from 2 to 10
> > > > >>cl <- kmeans(x, i, 20)
> > > > >>plot(x, col = cl$cluster)
> > > > >>points(cl$centers, col = 1:i )
> > > > >>
> > > > >>I see that there are only 8 colours defined , namely
> > > > >>black,red,green,blue,cyan,magenta,yello,gray.
> > > > >>
> > > > >>How should i set my colour preferences to obtain my palette
> > > > >>of colours? I
> > > > >>checked in the totorial which talks about R.colors and
> > > > >>palatte , but i
> > > > >>failed to understand how to set it.
> > > > >>
> > > > >>Thank You
> > > > >>
> > > > >>Asha
> > > > >>
> > > > >>
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