Getting Coordinates from plot

• To: mathgroup at smc.vnet.net
• Subject: [mg32953] Getting Coordinates from plot
• From: Winston Garira <uceswga at ucl.ac.uk>
• Date: Thu, 21 Feb 2002 02:07:08 -0500 (EST)
• Reply-to: Winston Garira <uceswga at ucl.ac.uk>
• Sender: owner-wri-mathgroup at wolfram.com

```Hi,

Can someone help me on this one.
I would like a list of coordinates so that I can analyze them further
and possibly import into a "prettier" graphing package. What should
I do when using the NDSolve function?

I have tried the menu command: Input -> Get Graphics Coordinates.
This requires me to use Mod1 key which I don't have on my keyboard.

How can I get coordinates of the plot from the following:

Pends[init1_, init2_, time_, k_, {c_, w_, p_}] :=
Module[{},
pend = NDSolve[{
x1''[t] + c x1'[t] + ((1 + p Cos[w t])) Sin[x1[t]] == k (x2[t] - x1[t]),
x2''[t] + c x2'[t] + ((1 + p Cos[w t])) Sin[x2[t]] == k (x1[t] - x2[t]),
x1[0] == init1[[1]], x1'[0] == init1[[2]],
x2[0] == init2[[1]], x2'[0] == init2[[2]]},
{x1, x2}, {t, 0, time},
MaxSteps -> 200000];
xd[t_] := x1[t] /. pend[[1]];
xdd[t_] :=x1'[t] /.pend[[1]];
xr[t_] := x2[t] /. pend[[1]];
xrd[t_] :=x2'[t] /.pend[[1]];
];
c = 0.1;  w = 2.0;  p = 2.0;
Pends[{1.37, 0}, {-1.17, 0}, 5000, 0.0, {c, w, p}];
ParametricPlot[{ {xd[t], xdd[t]}, {xr[t], xrd[t]}}, {t, 1000, 1500}];

Winston

```

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