Hi, Would like to make an image however the values in z are not on an uniform grid. Have a dataset with length(x) == length(y) == length(z) x[1],y[1] gives the position of z[1] and would like to encode value of z by a color. looking for something like plot(x,y, col = z) where col for z is cleverly chosen from a colorscale. Hope I made clear what I am looking for. Thanks Eryk
Hi,
Not really sure what you are after, but the following plots a series of
points of varying colour
plot(x,y,type='n')
apply(cbind(x,y,z),1,function(a) {points(a[1],a[2],col=a[3],pch=".")})
but its going to be really slow for a large number of points
Martyn
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of W Eryk Wolski
Sent: 06 August 2010 15:25
To: r-help at r-project.org
Subject: [R] image plot but data not on grid.
Hi,
Would like to make an image
however the values in z are not on an uniform grid.
Have a dataset with
length(x) == length(y) == length(z)
x[1],y[1] gives the position of z[1]
and would like to encode value of z by a color.
looking for something like
plot(x,y, col = z)
where col for z is cleverly chosen from a colorscale.
Hope I made clear what I am looking for.
Thanks
Eryk
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On Aug 6, 2010, at 10:24 AM, W Eryk Wolski wrote:> Hi, > > Would like to make an image > however the values in z are not on an uniform grid. > > Have a dataset with > length(x) == length(y) == length(z) > x[1],y[1] gives the position of z[1] > > and would like to encode value of z by a color. > > looking for something like > plot(x,y, col = z) > where col for z is cleverly chosen from a colorscale.?palette ??palette # for other coloring options ?colorRamp # random integer index from default palette for coloring of random x,y points: plot(rnorm(20), rnorm(20), col=palette()[ runif(20, 1,10) ] ) # The cleverness is left to you. -- David Winsemius, MD West Hartford, CT
On Fri, Aug 6, 2010 at 9:24 AM, W Eryk Wolski <wewolski at gmail.com> wrote:> Hi, > > Would like to make an image > however the values in z are not on an uniform grid. > > Have a dataset with > length(x) == length(y) == length(z) > x[1],y[1] gives the position of z[1] > > and would like to encode value of z by a color. > > looking for something like > plot(x,y, col = z) > where col for z is cleverly chosen from a colorscale.library(ggplot2) qplot(x, y, fill = z, data = df, geom = "tile") Hadley -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/