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Re: Vectorlength independet of axis-scale using VectorPlot?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg124465] Re: Vectorlength independet of axis-scale using VectorPlot?
  • From: "Oleksandr Rasputinov" <oleksandr_rasputinov at hmamail.com>
  • Date: Fri, 20 Jan 2012 01:54:51 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <jf8veo$5pb$1@smc.vnet.net>

On Thu, 19 Jan 2012 11:40:08 -0000, Robert Steinfelder  
<rsteinfe at techfak.uni-bielefeld.de> wrote:

> Hi,
>
> given the following code:
>
> \[Gamma] := 3
> a := 0.3
> \[Epsilon] := 0.1
>
> graphs := Plot[{-v*(v - a)*(v - 1), v/\[Gamma]}, {v, -0.4, 1.5},
>   PlotRange -> {{-0.4, 1.3}, {-0.2, 0.3}},
>   PlotStyle -> {{Black, Thick}, {Black, Thick}}, AspectRatio -> 1,
>   AxesStyle -> Arrowheads[0.03] ]
>
> vecs := VectorPlot[{-v*(v - a)*(v - 1) -
>     w, \[Epsilon]*(v - \[Gamma]*w)}, {v, -0.4, 1.2}, {w, -0.2, 0.3},
>   Axes -> True, VectorPoints -> 15,
>   VectorScale -> {0.03, Scaled[1], None}]
>
> Show[graphs, vecs, AxesLabel -> {"v", "w"}, AspectRatio -> 1]
>
> The vectors of this vectorfield have all the same (absolute) length, of
> course. But
> due to the axis-scale, vectors in vertical orientatian are plottet
> longer than
> the others. Is it possible to correct that, so that all the
> vectors have the same (relative) length?
>
> Regards,
>  Rob
>

The way that seems to make most sense to me is to set AspectRatio ->  
Automatic. Of course, this means you end up with a plot having an unusual  
aspect ratio, but if you want the vectors to be of the same relative size  
yet still quantitatively meaningful I'm not sure that there's a better way  
to accomplish this.



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