[Date Index] [Thread Index] [Author Index]

RE: PlotVectorField

• To: mathgroup at smc.vnet.net
• Subject: [mg34791] RE: [mg34785] PlotVectorField
• From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
• Date: Fri, 7 Jun 2002 01:08:53 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

> -----Original Message-----
> From: shollis at armstrong.edu [mailto:shollis at armstrong.edu]
To: mathgroup at smc.vnet.net
> Sent: Thursday, June 06, 2002 7:55 AM
> Subject: [mg34791] [mg34785] PlotVectorField
> 
> 
> I have a situation where I need to PlotVectorField with a specific
> PlotRange. For example,
> 
> <<Graphics`PlotField`;
> PlotVectorField[{1,4-x^2-y^2},{x,-3,3},{y,-3, 3},
>   ScaleFunction->(1&), PlotPoints -> 9, ScaleFactor -> 0.75,
>   PlotRange->{{-3.2, 3.2},{-3.2, 3.2}}]
> 
> As happens with that example, arrows near the edge often get chopped
> off. That's to be expected. What I'd like to do is use PlotRegion to
> create ``margins" around the plot so that all the arrows are fully
> visible. For example,
> 
> PlotVectorField[{1,4-x^2-y^2},{x,-3,3},{y,-3, 3},
>   ScaleFunction->(1&), PlotPoints -> 9, ScaleFactor -> 0.75,
>   PlotRange->{{-3.2, 3.2},{-3.2, 3.2}}, PlotRegion->{{.1,.9},{.1,.9}}]
> 
> This brings the heads of the arrows back into the picture, but the
> lines don't connect with the heads. In other instances, heads get
> drawn badly and look like boxes.
> 
> Short of changing the PlotRange, xmin, xmax, ymin, ymax values, is
> there some better way to do this?
> 
> And is this an ``issue" with PlotVectorField?
> 
> Thanks in advance,
> 
> Selwyn
> 

Selwyn,

if you generate your Graphics object as

p0 = PlotVectorField[{1, 4 - x^2 - y^2}, {x, -3, 3}, {y, -3, 3}, 
    ScaleFunction -> (1 &), PlotPoints -> 9, ScaleFactor -> 0.75, 
    PlotRange -> {{-3.2, 3.2}, {-3.2, 3.2}}]

then you'll get intact arrows if you get rid off all options:

Show[Graphics[p0[[1]]], AspectRatio -> Automatic, 
  Background -> Hue[.1, .1, 1], Frame -> True]

It appears as if in p0 Arrows were partially hidden by the labelling of the
FrameTicks, even if FrameTicks -> None or Frame -> False.

There may be more subtle ways to suppress the undesired effects, but this
will take some time playing with the options.

--
Hartmut