[R] persp/ scatterplot3d
Petr Pikal
petr.pikal at precheza.cz
Wed Jun 28 16:44:16 CEST 2006
Hi,
there was some thread recently about image, contour, persp.
from persp help page
x, y locations of grid lines at which the values in z are measured.
These must be in **ascending order**. By default, equally spaced
values from 0 to 1 are used. If x is a list, its components x$x and
x$y are used for x and y, respectively.
z a **matrix** containing the values to be plotted (NAs are allowed).
Note that x can be used instead of z for convenience.
so generally
persp(ascending.vector.with.nrow.length,
ascending.vector.with.ncol.length,
matrix.with.nrows.and.ncols)
or
persp(x.coords, y.coords, matrix.of.z.values)
is the necessary input. Something like geographical grid and value
for each set of coordinates.
Or you can use interp function from akima package.
HTH
Petr
From: Mark Hempelmann <e.rehak_at_t-online.de>
Date: Wed 28 Jun 2006 - 22:55:35 EST
Dear WizaRds,
I would like to create a 3d-plot with persp(). I sampled 17
points with xyz-coordinates (real-life example!), representing the
peaks of the whole plane with "zero coordinates" x=3,y=3,z=3. My
intention is to show which entries are above or below the "zero"
level with persp() on a nicely created grid. I also tried
scatterplot3d(), but, alas, I am unable to tell the function that my
points represent the peaks of the plane and are either above or below
"normal" (whatever that means...) Please help me:
dat<-
matrix(c(1.33,1.00,2.67,4.33,4.00,5.00,0.67,3.33,1.00,3.00,3.00,1.33,1
.67,1.67,1.33,1.67,2.33,1.67,0.67,1.00,1.33,3.33,2.67,1.67,1.67,2.67,2
.00,0.33,0.67,0.33,2.67,3.33,0.67,0.67,1.33,0.00,4.33,3.33,4.67,3.00,4
.00,5.00,4.00,3.67,1.67,3.00,3.67,3.33,1.00,1.33,0.33), ncol=3)
colnames(dat)<-c("x","y","z")
x=dat$x; y=dat$y, z=dat$z
persp(x,y,z) # doesn't work at all, of course, even if I utilize
outer()
scatterplot3d(x,y,z) # returns a 3d scatterplot, but not the way I
would like to see it fit.
Thank you so much for your help and support!
mark
Petr Pikal
petr.pikal at precheza.cz
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