[R] wireframe() display a graph with two colors, not a gradient.

[Deepayan Sarkar]

On Sun, Feb 27, 2011 at 1:29 AM, James Platt <james-platt at hotmail.co.uk> wrote:
> Hi all,
>
> I'm quite new to wireframe, essentially what I want to do is display a graph, and z-values > 1 would be yellow and those < 1 would be blue.
> This is a bit of my data.
>
> 0.334643563     0.350913807     0.383652307
> 0.370325283     0.38779016      0.42387392
> 0.39861579      0.418389687     0.460692165
> 0.43888516      0.468015843     0.520560489
> 0.499544084     0.535099422     0.60982153
> 0.569888047     0.634351734     0.717646392
> 0.717202578     0.810887467     0.935152498
> 0.901982916     1.044895388     1.228306176
> 1.12856184      1.314210456     1.462055626
> 1.377314404     1.540372345     1.6206216
> 1.494044604     1.618244219     1.631295797
>
>
>
>
>
> data.m = as.matrix(read.table("/Users/James/Desktop/c.txt", sep='\t'))
> library(lattice)
> wireframe(data.m,aspect = c(0.3), shade=TRUE, screen = list(z = 0, x = -45), light.source = c(0,0,10), distance = 0.2)
>
> i know I probably need to use the col.regions or level.colors argument, but I'm not sure what I actually need to supply to the arguments to get it to work.
> All the examples I've seen also have a gradient of color between two or more colors, I want to color half the graph with z values > 1 yellow, and <1 blue.

Something like

wireframe(volcano, drape = TRUE, at = c(90, 150, 200))

perhaps? Note that color may not vary within a quadrilateral, so your
boundary will be jagged to some extent.

-Deepayan