Re: [R] Plot a sphere
Uwe,
Thanks, I installed it and ran:
rgl.spheres(rnorm(10),rnorm(10),rnorm(10),radius=1,color=rainbow(10))
Nice :)
Thus, I'll give rgl a try but still would be 'stuborn' to see if I can
figure a way out to use persp.
Regards,
D.
From: Uwe Ligges [EMAIL PROTECTED]
To: Spencer Graves [EMAIL PROTECTED]
CC: Derick Schoonbee [EMAIL PROTECTED],[EMAIL PROTECTED]
Subject: Re: [R] Plot a sphere
Date: Fri, 26 Dec 2003 12:48:49 +0100
Spencer Graves wrote:
A hemisphere is relatively easy; try the following:
x - seq(-1, 1, length=21)
Z - outer(x, x, function(x, y)sqrt(1-x^2-y^2))
persp(x=x, y=x, z=Z)
A contour plot is also relatively easy:
image(x=x, y=x, z=Z)
contour(x=x, y=x, z=Z, add=T)
However, if you want an honest perspective plot of a sphere
complete with the underside, etc., I know of nothing in R that could do
that. S-Plus has perspp, which could be used. However, that seems to
be one of the few features available in S-Plus that is not currently
available in R.
The R package rgl by Adler and Nenadic can plot spheres. It is
available at
http://wsopuppenkiste.wiso.uni-goettingen.de/~dadler/rgl/
--- and looks like it will shortly become a CRAN package.
Uwe Ligges
hope this helps.
spencer graves
Derick Schoonbee wrote:
Hi,
I'm new to R (and math ;) Would somebody please be so kind as to
direct me in plotting a 3D sphere?
I tried something in the lines of:
y - x - seq(-pi, pi, length=pi*10)
f - function(x,y)
{
z - sqrt(pi - x^2 - y^2)
#z[is.na(z)] - 0
z
}
z - outer(x, y, f)
persp(x, y, z, theta = 120, phi = 30)
I've also tried: make.surface.grid(...) .. persp( as.surface(
grid, z) ) ... with the same result: 'Incomplete' demi sphere and
others..
Any suggestions/solutions would be appreaciated.
Regards,
Derick
PS:Merry X-mas ;)
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Re: [R] Plot a sphere
Hi,
Thank you all for the solutions.. I now have 3 ways of plotting a 'perfect'
sphere :)
1 rgl
2 scatterplot3d
3 persp (with polygon) as below.
Personally I like the transformation solution as in 3. Thanks a mill.
Derick Schoonbee
From: David Brahm [EMAIL PROTECTED]
Reply-To: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
Subject: Re: [R] Plot a sphere
Date: Fri, 26 Dec 2003 10:29:08 -0500
Derick Schoonbee [EMAIL PROTECTED] wrote:
Would somebody please be so kind as to direct me in plotting a 3D sphere?
Here's one way. I generate an empty 3D plot with persp, then fill it with
polygons transformed with trans3d (as found in the help for persp). I
didn't do hidden surface removal (you didn't mention whether you wanted it),
but if you do, just reorder the polygons from back to front and paint
them
a solid color (e.g. col=red), so hidden ones get painted over.
pmat - persp(0:1, 0:1, matrix(,2,2), xlim=c(-1,1), ylim=c(-1,1),
zlim=c(-1,1),
theta=25, phi=30, expand=.9, xlab=X, ylab=Y, zlab=Z)
trans3d - function(x,y,z, pmat) { # From the help for
persp
tr - cbind(x,y,z,1) %*% pmat
list(x = tr[,1]/tr[,4], y= tr[,2]/tr[,4])
}
theta - seq(0, 2*pi, length=51)
phi - seq(0, pi, length=26)
x - cos(theta) %o% sin(phi)
y - sin(theta) %o% sin(phi)
z - rep(1, length(theta)) %o% cos(phi)
for (j in seq(phi)[-1]) for (i in seq(theta)[-1]) {
idx - rbind(c(i-1,j-1), c(i,j-1), c(i,j), c(i-1,j))
polygon(trans3d(x[idx], y[idx], z[idx], pmat))
}
--
-- David Brahm ([EMAIL PROTECTED])
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Re: [R] Plot a sphere
Thanks for the reply. The results are exactly the same as what I'm getting.
Now I'm thinking in the lines of:
z1 - outer(x, y, f)
z2 - -outer(x, y, f)
So, I want to attach the two hemispheres. But then I need to figure out how
append vectors z1 z2 and then 'feed' this to persp..
hmm, I'll look into it.
Regards,
D.
From: Spencer Graves [EMAIL PROTECTED]
To: Derick Schoonbee [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
Subject: Re: [R] Plot a sphere
Date: Thu, 25 Dec 2003 17:38:01 -0800
A hemisphere is relatively easy; try the following:
x - seq(-1, 1, length=21)
Z - outer(x, x, function(x, y)sqrt(1-x^2-y^2))
persp(x=x, y=x, z=Z)
A contour plot is also relatively easy:
image(x=x, y=x, z=Z)
contour(x=x, y=x, z=Z, add=T)
However, if you want an honest perspective plot of a sphere complete
with the underside, etc., I know of nothing in R that could do that. S-Plus
has perspp, which could be used. However, that seems to be one of the few
features available in S-Plus that is not currently available in R.
hope this helps. spencer graves
Derick Schoonbee wrote:
Hi,
I'm new to R (and math ;) Would somebody please be so kind as to direct me
in plotting a 3D sphere?
I tried something in the lines of:
y - x - seq(-pi, pi, length=pi*10)
f - function(x,y)
{
z - sqrt(pi - x^2 - y^2)
#z[is.na(z)] - 0
z
}
z - outer(x, y, f)
persp(x, y, z, theta = 120, phi = 30)
I've also tried: make.surface.grid(...) .. persp( as.surface( grid, z)
) ... with the same result: 'Incomplete' demi sphere and others..
Any suggestions/solutions would be appreaciated.
Regards,
Derick
PS:Merry X-mas ;)
__
[EMAIL PROTECTED] mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help
__
[EMAIL PROTECTED] mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help
[R] Plot a sphere
Hi,
I'm new to R (and math ;) Would somebody please be so kind as to direct me
in plotting a 3D sphere?
I tried something in the lines of:
y - x - seq(-pi, pi, length=pi*10)
f - function(x,y)
{
z - sqrt(pi - x^2 - y^2)
#z[is.na(z)] - 0
z
}
z - outer(x, y, f)
persp(x, y, z, theta = 120, phi = 30)
I've also tried: make.surface.grid(...) .. persp( as.surface( grid, z)
) ... with the same result: 'Incomplete' demi sphere and others..
Any suggestions/solutions would be appreaciated.
Regards,
Derick
PS:Merry X-mas ;)
__
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