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extracting contour points

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  • Subject: [mg92447] extracting contour points
  • From: peterp <peterp at>
  • Date: Tue, 30 Sep 2008 21:54:39 -0400 (EDT)

Hello all,

I've searched the group but I still have a problem. The contour sought
below returns two lines (you can actually see them on the graphic output).
The commands after the contour plot only extract the coordinates of one
of the two lines. How do I get the second ?
I tried replacing "First" by "Second" but no dice.


f[p_, a_, x_] = - p x + x^(a + 1)

contour =
  ContourPlot[Arg[f[1, .6, x + I y]], {x, -2, 2}, {y, -2, 2}, Contours
-> {0},
     ContourShading -> False, PlotPoints -> 100]

grcontour = Graphics[contour];
lns = First[
      Cases[First[grcontour] // Normal, Line[pts_] -> pts, \
dat = Table[lns];
Export["junk.dat", Re[dat]]

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