[R-sig-Geo] ramping four color in xy space

[Marcelino de la Cruz]

Nice plot!

It could be even more similar to  the one in 
http://www.flickr.com/photos/erniebooth/183647844/ 
if you substitute pch=15 for pch =19

Cheers,

Marcelino


At 08:33 19/11/2008, Holger Kreft wrote:
>Dear Tom,
>
>Thanks a lot for your swift reply. While your 
>script wasn't exactly doing what I wanted, it 
>brought me on the right track. Here is the code that I finally used.
>Probably not super elegant, but it does the job 
>and I thought it be useful for others.
>
>Cheers,
>
>Holger
>
>--
>
>my.data<-seq(0,1,.01)
>
>my.class<-classIntervals(my.data,n=100,style="equal")
>my.pal.1<-findColours(my.class,c("yellow","red"))
>my.pal.2<-findColours(my.class,c("green","blue"))
>
>plot(rep(0,101),my.data,pch=19,col=my.pal.1, cex=1, xlim=c(0,1),ylim=c(0,1))
>points(rep(1,101),my.data,pch=19,col=my.pal.2, cex=1)
>
>#------------------------------------
># loop: use left and right vertical
># color ramp & interpolate horizontally
>#------------------------------------
>
>col.matrix<-matrix(nrow = 101, ncol = 101, NA)
>
>for(i in 1:101){
>my.col<-c(paste(my.pal.1[i]),paste(my.pal.2[i])) # choose colors
>col.matrix[102-i,]<-findColours(my.class,my.col)
>}
>
>#------------------------------------
># plot full grid
>#------------------------------------
>
>plot(rep(0,101),my.data,pch=19,col=my.pal.1, cex=0.5, xlim=c(0,1),ylim=c(0,1))
>
>for(i in 1:101){
>col.temp<-col.matrix[i-1,]
>points(my.data,rep((i-1)/100,101),pch=19,col=col.temp, cex=1)
>}
>
>
>
>
>Tomislav Hengl schrieb:
>>Dear Holger,
>>
>>This is a small script that uses [colorspace] 
>>library to run calculations with colors (some methods
>>are limited to 256 colors only):
>>
>>http://spatial-analyst.net/scripts/whitening.R
>>
>>If you assign R,G,B values spatially and then 
>>interpolate them (they have to be in the 0-1 range),
>>then it is relatively easy to produce an RGB image.
>>
>>cheers,
>>
>>Tom Hengl
>>http://spatial-analyst.net/wiki/index.php?title=Uncertainty_visualization
>>
>>PS: maybe you should also consider color mixing:
>>
>>Hengl T., Walvoort D.J.J., Brown A. 2004. A 
>>double continuous approach to visualisation and analysis
>>of categorical maps. Int. Jou. of Geographical 
>>Information Science, 18(2): 183-202.
>>http://dx.doi.org/10.1080/13658810310001620924
>>
>>-----Original Message-----
>>From: r-sig-geo-bounces at stat.math.ethz.ch 
>>[mailto:r-sig-geo-bounces at stat.math.ethz.ch] On Behalf Of
>>Holger Kreft
>>Sent: Tuesday, November 18, 2008 9:38 AM
>>To: R-sig-Geo at stat.math.ethz.ch
>>Subject: [R-sig-Geo] ramping four color in xy space
>>
>>Hi,
>>
>>I have run a metaMDS(vegan) on ecological 
>>community data and have a nice plot in xy space.
>>What I want to do next is to assign a unique 
>>color to each point in the plot and then look 
>>at how these communities map out in geographic space.
>>So, each corner of the plot has a color (let's 
>>say green, blue, red and yellow). I guess I 
>>have to ramp the colors for the space inbetween.
>>The right plot here illustrate how the palette 
>>should look like: http://www.flickr.com/photos/erniebooth/183647844/
>>
>>Does anyone have experience in ramping four 
>>colours in 2-D? I looked at a lot of packages, 
>>but they are all not doing what I want.
>>
>>Any hint / help is greatly appreciated!
>>
>>Thanks,
>>
>>Holger
>>
>>_______________________________________________
>>R-sig-Geo mailing list
>>R-sig-Geo at stat.math.ethz.ch
>>https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>>_______________________________________________
>>R-sig-Geo mailing list
>>R-sig-Geo at stat.math.ethz.ch
>>https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>>
>
>
>--
>****************************************************************
>Dr. Holger Kreft
>Phone:  ++1-858-5346659
>Email:  hkreft at ucsd.edu
>www.uni-bonn.de/~uzsxeg
>Ecology Behavior & Evolution Section
>Division of Biological Sciences
>University of California, San Diego
>9500 Gilman Drive, MC 0116
>La Jolla, CA 92093-0116, USA
>http://www-biology.ucsd.edu/labs/jetz/
>
>_______________________________________________
>R-sig-Geo mailing list
>R-sig-Geo at stat.math.ethz.ch
>https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
>
>---------------------------------------------------------------------------------------------------
>Texto añadido por Panda IS 2008:
>
>Este mensaje NO ha sido clasificado como SPAM. 
>Si se trata de un mensaje de correo no 
>solicitado (SPAM), haz clic en el siguiente 
>vínculo para reclasificarlo: 
>http://localhost:6083/Panda?ID=pav_2562&SPAM=true&path=C:\Documents%20and%20Settings\mcr\Configuración%20local\Datos%20de%20programa\Panda%20Software\AntiSpam
>---------------------------------------------------------------------------------------------------

________________________________

Marcelino de la Cruz Rot

Departamento de  Biología Vegetal
E.U.T.I. Agrícola
Universidad Politécnica de Madrid
28040-Madrid
Tel.: 91 336 54 35
Fax: 91 336 56 56
marcelino.delacruz at upm.es