Re: Getting Coordinates from plot
- To: mathgroup at smc.vnet.net
- Subject: [mg32967] Re: [mg32953] Getting Coordinates from plot
- From: BobHanlon at aol.com
- Date: Fri, 22 Feb 2002 01:48:50 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
In a message dated 2/21/02 4:04:10 AM, uceswga at ucl.ac.uk writes:
>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}];
>
plt = ParametricPlot[{ {xd[t], xdd[t]}, {xr[t], xrd[t]}}, {t, 1000, 1500}];
The data for the first plot is plt[[1, 1, 1, 1, 1]]
The second plot is plt[[1, 2, 1, 1, 1]]
To compare with the original plot
Needs["Graphics`Graphics`"];
DisplayTogether[
ListPlot[plt[[1, 1, 1, 1, 1]], PlotJoined -> True],
ListPlot[plt[[1, 2, 1, 1, 1]], PlotJoined -> True]];
Bob Hanlon
Chantilly, VA USA