extracting points and projecting

*To*: mathgroup at smc.vnet.net*Subject*: [mg98099] extracting points and projecting*From*: "Cristina Ballantine" <cballant at holycross.edu>*Date*: Mon, 30 Mar 2009 04:42:57 -0500 (EST)

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

**Follow-Ups**:**Re: extracting points and projecting***From:*DrMajorBob <btreat1@austin.rr.com>