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Re: ListPlot & lots 'o dots.

  • To: mathgroup at smc.vnet.net
  • Subject: [mg87797] Re: ListPlot & lots 'o dots.
  • From: David Bailey <dave at Remove_Thisdbailey.co.uk>
  • Date: Wed, 16 Apr 2008 22:35:51 -0400 (EDT)
  • References: <fu4flb$nj7$1@smc.vnet.net>

Annetts729 wrote:
> Hi,
> 
> Apparently ListPlot has a quirk on my systems (XP SP2/3, 6.0.2)
> 
> With test data
> 
>   test = Table[N@Sin[n \[Pi] x], {n, 1, 5, 1}, {x, -\[Pi], \[Pi], \
> [Pi]/50}];
> 
> ListPlot[test] produces a plot with lots 'o dots as expected.  It's
> easy to see which dots correspond to which frequency by connecting
> points in each data set
> 
>   ListPlot[test, Joined->True]
> 
> We can correct the ordinate scale using
> 
>   ListPlot[test, Joined->True, DataRange->{-\[Pi], \[Pi]}], and for
> lots 'o plots this looks messy.
> 
> Using SetOptions, we can set ListPlot up so that we don't need to
> specify Joined & a data range every time we use ListPlot using
> 
>   SetOptions[ListPlot, DataRange -> {-\[Pi], \[Pi]}, Joined ->
> True ];
> 
> We can confirm ListPlot's new settings either by removing the ";" or
> using Options@ListPlot.
> 
> For me this is where the problem starts.
> 
> After an appropriate SetOptions (like above), ListPlot[test] should
> give me a plots that is joined & has the correct ordinate scale.  For
> me it doesn't, despite Joined->True and DataRange, ListPlot[test] gets
> ma a plot with lots 'o dots and the wrong scale.  I know there's a
> point to SetOptions since I can set (eg) a PlotRange and FrameLabels.
> It's just that ListPlot (apparently) ignores DataRange & Joined so
> that I have to specify them each time I use ListPlot.
> 
> I'd like to know if this problem restricted to my system.  In the
> event that it can be reproduced, I'll report it as a bug.
> 
> Tests.
> test = Table[N@Sin[n \[Pi] x], {n, 1, 5, 1}, {x, -\[Pi], \[Pi], \[Pi]/
> 50}]; (* generate test data *)
> ListPlot[test] (* plot w/ lots o dots *)
> ListPlot[test, Joined -> True, DataRange -> {-\[Pi], \[Pi]}] (*
> desired plot *)
> SetOptions[ListPlot, DataRange -> {-\[Pi], \[Pi]}, Joined -> True,
> FrameLabel -> {"Hi", "Lo"}, PlotRange -> {0,  [Pi]/2}]; (* set default
> options for ListPlot *)
> ListPlot[test] (* dotty plot, incorrect ordinate but correct abscissa
> & labels -- WTF? *)
> 
> 
> Regards,
> 
> Dave.
> 
> 
> 
> 
> 
> 
It would seem that ListPlot is not responding to changed options! 
Although this is a bug, I would not recommend setting the options of 
built-in functions because it can cause confusion over time. A better 
approach is to define your own plotting function which calls ListPlot 
with the required options.

David Bailey
http://www.dbaileyconsultancy.co.uk


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