Path: news.mathworks.com!not-for-mail
From: "Charles Cuell" <cuell@math.usask.ca>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Plot trajectories on a sphere?
Date: Wed, 9 Jan 2008 18:58:02 +0000 (UTC)
Organization: Environment Canada
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"Anil Seth" <a.k.seth.nospamplease@sussex.ac.uk> wrote in 
message <fm2li8$ntr$1@fred.mathworks.com>...
> I would be VERY grateful for advice.  Basically I want to
> plot an x,y trajectory on the surface of a sphere.  The 
data
> I have are in the following form:
> 
> x: a vector (N) in [-200,200] 
> y: a vector (N) in [-200,200]
> 
> NB these vectors are toroidal in the sense that -201 maps 
to
> 199.
> 
> What I want:
> 
> plot these trajectories on a sphere of fixed radius (ie 
non
> deformed). 
> 
> Simple question:  If all this is too much, just tell me 
how
> to plot a line on the surface of a sphere!
> 
> Thanks!
> 
> Thanks

If your data vectors, x and y, are already "toroidal", then 
I presume that means they are representing angles?  If that 
is the case then the x and y are representing points on the 
surface of a torus and you need a transformation that takes 
points on a torus to points on a sphere. If so, the trouble 
is that a sphere is not a torus and there is no nice 
transformation.    
 
Charles