Combining two paramteric plots into one.
- To: mathgroup at smc.vnet.net
- Subject: [mg49094] Combining two paramteric plots into one.
- From: Bob Harris <nitlion at mindspring.com>
- Date: Thu, 1 Jul 2004 05:25:39 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Howdy,
I'm trying to plot two ellipses together on one plot. I have accomplished
this, except that mathematica plots three figures-- ellipse 1, then ellipse
2, then the combination of the two. I want to avoid the first two figures.
Here's what I am doing.
ellipsePoint[{xc_, yc_, w_, h_, a_}, t_] :=
{((w Cos[a] Cos[t] - h Sin[a] Sin[t]) + xc)/2,
((w Sin[a] Cos[t] + h Cos[a] Sin[t]) + yc)/2}
ellipsePlot[{xc_, yc_, w_, h_, a_}] :=
ellipsePlot[{xc, yc, w, h, a}, 20]
ellipsePlot[{xc_, yc_, w_, h_, a_}, n_] :=
ParametricPlot[
{ellipsePoint[{xc, yc, w, h, a}, 2\[Pi] t/n][[1]],
ellipsePoint[{xc, yc, w, h, a}, 2\[Pi] t/n][[2]]},
{t, 0, n},
AspectRatio -> Automatic]
ellipsePlotTwo[{xc1_, yc1_, w1_, h1_, a1_},
{xc2_, yc2_, w2_, h2_, a2_}] :=
Show[
ellipsePlot[{xc1, yc1, w1, h1, a1}],
ellipsePlot[{xc2, yc2, w2, h2, a2}]]
Apparently what happens is ParametricPlot[...] always draws a figure so when
I call it inside Show (via ellipsePlot[...]), I get a figure drawn that I
don't want to draw yet. How can I call ParametricPlot and just get the
resulting graphical object without it drawing it?
I have similar problems with other combinations with ellipsePlot. For
example, using ListPlot to try to add a list of points on the figure (i.e.
Show[ellipsePlot[...], ListPlot[...]]) I get three figures instead of just
the one I want.
Thanks,
Bob H