Re: Problems with ContourPlot

• To: mathgroup at smc.vnet.net
• Subject: [mg16869] Re: [mg16855] Problems with ContourPlot
• From: "Kevin J. McCann" <kevinmccann at Home.com>
• Date: Mon, 5 Apr 1999 02:24:15 -0400
• References: <199904020235.VAA11450@smc.vnet.net.>
• Sender: owner-wri-mathgroup at wolfram.com

```Not an expert; so, I will only do (1) and (2):

f1[x_,y_]:=3 x+5 y-9
f2[x_,y_]:= 5x-3y-9

xmin=-1;
xmax=1;
ymin=-1;
ymax=1;

fig1 = ContourPlot[f1[x, y], {x, xmin, xmax},
{y, ymin, ymax}, ContourShading -> False,
ContourStyle -> RGBColor[1, 0, 0], PlotPoints -> 50];

fig2 = ContourPlot[f2[x, y], {x, xmin, xmax},
{y, ymin, ymax}, ContourShading -> False,
ContourStyle -> RGBColor[0, 0, 1], PlotPoints -> 50];

Show[fig1,fig2];

Kevin

----- Original Message -----
From: Marco PULLIA <marco.pullia at cern.ch>
To: mathgroup at smc.vnet.net
Subject: [mg16869] [mg16855] Problems with ContourPlot

> Hello to everybody,
> I have a couple of questions for you experts:
> 1) I have produced two ContourPlots and I would like to show
>    them overlapped. I have tried
>
>    Fig1=ContourPlot[f1[x,y], {x,xmin,xmax}, {y,ymin,ymax},
>                     PlotRange->{zmin,zmax}]
>    Fig2=ContourPlot[f2[x,y], {x,xmin,xmax}, {y,ymin,ymax},
>                     PlotRange->{zmin,zmax}]
>    Show[Fig1,Fig2]
>
>    but it does not work. The problem is that the range in y is not
>    {ymin, ymax} but a much smaller one (0 to 10^-7), thus I just see
>    a useless part of it. How can I do that?
>
> 2) I generally use ContourShading -> False in order to get just some
>    curves. Is it possible to draw these curves in a color different from
>    black?
>
> 3) Is it possible to obtain the numerical values of points of the
>    iso-value curves? And to find the values of the constant expression?
>
>