Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2009

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: extracting points and projecting

  • To: mathgroup at smc.vnet.net
  • Subject: [mg98114] Re: extracting points and projecting
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Mon, 30 Mar 2009 05:19:50 -0500 (EST)
  • Organization: Uni Leipzig
  • References: <gqq3s0$7ml$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

g = ContourPlot[Arg[Gamma[x + I*y]] == 0, {x, -10, 10}, {y, -10, 10},
   PlotPoints -> 100];

j1[x_, y_] := 2 x/(1 + x^2 + y^2)^2
j2[x_, y_] := 2 y/(1 + x^2 + y^2)^2
j3[x_, y_] := (-1 + x^2 + y^2)/(1 + x^2 + y^2)

toSphere[{x_, y_}] := {j1[x, y], j2[x, y], j3[x, y]}


and

Graphics3D[
  g[[1]] /. GraphicsComplex[pnts_, more_, ___] :>
    GraphicsComplex[toSphere /@ pnts, more]]

Regards
   Jens

Cristina Ballantine wrote:
> I would like to extract the points from the following ContourPlot
> 
> g=ContourPlot[Arg[Gamma[x + I*y]] == 0, {x, -10, 10}, {y, -10, 10}, PlotPoints -> 100]
> 
> I can do this with
> 
> pts = First@Cases[g, x_GraphicsComplex :> First[x]]
> 
> Then I would like to map this list of points onto the Riemann sphere. The projection is performed through
> 
> j1[x_, y_] := 2 x/(1 + x^2 + y^2)^2
> j2[x_, y_] := 2 y/(1 + x^2 + y^2)^2
> j3[x_, y_] := (-1 + x^2 + y^2)/(1 + x^2 + y^2)
> 
> I need to generate a list of three dimensional points (j1[x,y], j2[x,y], j2[x,y]) from pts and plot them. I am unable to generate the list of three dimensional points. Any help is very much appreciated.
> 
> Cristina
> 


  • Prev by Date: Re: Re: Interpolation with Method->Spline
  • Next by Date: Grabbing the hierarchy of function names from Function Nav NB
  • Previous by thread: Re: extracting points and projecting
  • Next by thread: Re: extracting points and projecting