On Wed, 16 Feb 2005 15:44:00 +0200 Sander Oom wrote: > 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?
It does! cols is a vector of length 42 and only the first 30 are used. Try to use your persp call below with col = cols and col = cols[1:30]. Z > 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(0.064329041,0.117243316,0.161565116,0.19923015,0.231642175,0.2598 > >35539,0.284571226,>0.038507288,0.094184749,0.140959431,0.180803984,0 > >.215159105,0.245096084,0.271412845,>0.00775022,0.066198255,0.1154332 > >07,0.157494219,0.193836765,0.225569076,0.253518629,>-0.02820814,0.03 > >2958752,0.084661362,0.128946221,0.167320522,0.200892494,0.230504392, > >>-0.07003273,-0.005814512,0.048304039,0.094805358,0.135196637,0.1706 > >30435,0.201956395,>-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 > ______________________________________________ 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