Re: ContourPlot problem
- To: mathgroup at smc.vnet.net
- Subject: [mg15507] Re: ContourPlot problem
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Mon, 18 Jan 1999 23:47:11 -0500
- References: <77uukf$kb8@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Pedro A Santos wrote in message <77uukf$kb8 at smc.vnet.net>...
>When I give the command
>
>ContourPlot[(1-Exp[-1/((x)^2+(y)^2)/10]),{x,-1.0,1.0},{y,-1.0,1.0},
> PlotPoints ->{50,50},
> Contours -> {.1,.2,.3,.4,.5,.6,.7,.8,.9,.99, .99999999},
> ContourShading ->False]
>
>I get what would be to expect, i.e. all the contours. But if I change
>slightly the domain,
>say "{x,-1.1,1.1},{y,-1.1,1.1}", the majority of the contours
>disappear. And they do not appear even if I increase PlotPoints to 200
>or more.
>
>Does anybody know the reason of this strange behaviour? And how to avoid
>it?
Pedro,
This is caused by Mathematica showing only what it thinks is interesting
With "{x,-1.1,1.1},{y,-1.1,1.1}" the same data is available as in the
first case but not all of it is displayed.
ContourPlot[(1-Exp[-1/((x)^2+(y)^2)/10]),{x,-1.1,1.1},{y,-1.1,1.1},
PlotPoints ->{50,50},
Contours -> {.1,.2,.3,.4,.5,.6,.7,.8,.9,.99, .99999999}, ContourShading
->False];
We can correct this retrospectively using Show
Show[%, PlotRange->All];
or we can use the option in ContourPlot:
ContourPlot[(1-Exp[-1/((x)^2+(y)^2)/10]),{x,-1.1,1.1},{y,-1.1,1.1},
PlotPoints ->{50,50},
Contours -> {.1,.2,.3,.4,.5,.6,.7,.8,.9,.99, .99999999}, ContourShading
->False,
PlotRange -> All];
If we don't want to see everything we can specify the range of heights
by PlotRange -> {0,1.2}, for example.
Allan
---------------------
Allan Hayes
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