Thanks Peter!
Of course I only have (nx-1)(ny-1) facets in a x*y plot!
The help page line:
...
col the color(s) of the surface facets. Transparent colours are ignored. This is recycled to the (nx-1)(ny-1) facets.
...
just did not ring a bell.
In fact, it is still not clear to me why it recycles the ramp even though it has a surplus of colours (grey levels)! Why not just ignore the surplus colours?
Anyway it works,
Sander.
Peter Dalgaard wrote:
Sander Oom <[EMAIL PROTECTED]> writes:
Dear R users,
Could somebody tell me why the grey color ramp is repeated in this graph, eventhough the ramp values go from 0 to 1? I must be missing something obvious, but I can not see it!
z <- c(0.064329041,0.117243316,0.161565116,0.19923015,0.231642175,0.259835539,0.284571226, 0.038507288,0.094184749,0.140959431,0.180803984,0.215159105,0.245096084,0.271412845, 0.00775022,0.066198255,0.115433207,0.157494219,0.193836765,0.225569076,0.253518629, -0.02820814,0.032958752,0.084661362,0.128946221,0.167320522,0.200892494,0.230504392, -0.07003273,-0.005814512,0.048304039,0.094805358,0.135196637,0.170630435,0.201956395, -0.117878701,-0.050461393,0.005991829,0.054672666,0.097103088,0.134398711,0.167423957)
x <- c(0,1,2,3,4,5) y <- c(50, 100, 150, 200, 250, 300, 350) z <- matrix(z, nrow=length(x), ncol=length(y), byrow=TRUE)
#persp(x, y, z, theta = 30, phi = 30, expand = 0.5, # box= TRUE, axes= TRUE, ticktype = "detailed", main="Title of plot")
hgt <- (z - min(z))/ (max(z) - min(z)) z hgt cols <- grey(hgt) persp(x, y, z, col = cols, theta = 30, phi = 30, expand = 0.5, box= TRUE, axes= TRUE, ticktype = "detailed", main="Title of plot")
You have 30 facets and 42 colour values. Try it with
cols <- grey(hgt[-1,-1])
-- --------------------------------------------------------- Dr. Sander P. Oom Animal, Plant and Environmental Sciences University of the Witwatersrand Private Bag 3 Wits 2050 South Africa
Tel (work) +27 (0)11 717 64 04 Tel (home) +27 (0)18 297 44 51 Fax +27 (0)18 299 24 64
Email [EMAIL PROTECTED] Web www.oomvanlieshout.net/sander
______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
