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From: Johannes R. <ja...@ho...> - 2010-09-02 00:38:32
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Hello, I have a problem with gnuplot: When I do a polar plot, like e.g. set polar plot cos(t) the minus signs are missing on the axis, so the labels at the y-axis go 0.5 0.4 0.3 0.2 0.1 0 0.1 0.2 0.3 0.4 0.5 Any ideas? Kind regards, Johannes Rauh |
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From: Thomas S. <t.s...@fz...> - 2010-09-02 08:58:09
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set size square set polar set grid polar set rrange [-1:1] set xrange [-2:2] set yrange [-2:2] plot cos(t) Bugzilla from ja...@ho... wrote: > > > Hello, > > I have a problem with gnuplot: When I do a polar plot, like e.g. > > set polar > plot cos(t) > > the minus signs are missing on the axis, so the labels at the y-axis go > 0.5 0.4 0.3 0.2 0.1 0 0.1 0.2 0.3 0.4 0.5 > > Any ideas? > Kind regards, > > Johannes Rauh > > > ------------------------------------------------------------------------------ > This SF.net Dev2Dev email is sponsored by: > > Show off your parallel programming skills. > Enter the Intel(R) Threading Challenge 2010. > http://p.sf.net/sfu/intel-thread-sfd > _______________________________________________ > gnuplot-info mailing list > gnu...@li... > https://lists.sourceforge.net/lists/listinfo/gnuplot-info > > -- View this message in context: http://old.nabble.com/problems-with-polar-plot%3A-no-negative-axis-labels-tp29599731p29601953.html Sent from the Gnuplot - User mailing list archive at Nabble.com. |
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From: Johannes R. <ja...@ho...> - 2010-09-02 10:16:32
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@Mauricio: Thanks for the workaround to this "feature" ;-) @Marek: Thanks for the explanation. Is it a feature I can deactivate? My problem is the following: I want to plot something in the x-y-plane, using polar coordinates, so having a minus sign would be very nice. Cheers, Johannes Rauh > It's not an error, it's a feature. The numbers you read are NOT > y-values - you're plotting in polar coordinate system, aren't you? > So, what you see, is a set of r-values, and those are non-negative. > > Cheers, > Marek Gutowski > > Johannes Rauh wrote: > > Hello, > > > > I have a problem with gnuplot: When I do a polar plot, like e.g. > > > > set polar > > plot cos(t) > > > > the minus signs are missing on the axis, so the labels at the y-axis go > > 0.5 0.4 0.3 0.2 0.1 0 0.1 0.2 0.3 0.4 0.5 > > > > Any ideas? > > Kind regards, > > > > Johannes Rauh |
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From: Johannes R. <ja...@ho...> - 2010-09-02 13:51:06
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Thanks for the suggestion, but rrange is the wrong thing: In polar mode gnuplot> set rrange [0:10] gnuplot> plot t does the same thing as gnuplot> set rrange [-5:5] gnuplot> plot t-5 (in other words, the lower bound of the rrange will always correspond to the origin, and the rest is shifted) I'm just wondering, because if I look at the great page http://t16web.lanl.gov/Kawano/gnuplot/polar-e.html (which is, by now, a bit outdated, but still very useful) I see that this behaviour must have changed some versions ago. While I admit that this behaviour has some justification, at least for my applications it does not make sense. And using a multiplot insert is a bit overkill just for plotting the axis labels. Meanwhile I found another solution to my problem: Specifying the axis labels one by one does work, e.g: set xtics ("7" 7, "6" 6, "5" 5, "4" 4, "3" 3, "2" 2, "1" 1, "0" 0, "-1" -1, "-2" -2, "-3" -3, "-4" -4, "-5" -5) plot t Cheers, Johannes Rauh > From: gu...@if... > > As Thomas Sefzick has shown, you can play with 'rrange', up to making > its lower bound negative. > BUT, note: > 1. both coordinates will be non-monotoneus then, and worse yet > 2. the shape of your curve may be substantially different (test Thomas' > example, see the result, and continue with: > > gnuplot> set rrange[*:*] > > gnuplot> replot > ) > Maybe you should consider making your polar plot to be an insert to the > regular picture, in usual, Cartesian coordinates. For this you should > rather consult/consider the 'multiplot' mode. > > Cheers, > Marek Gutowski > > Johannes Rauh wrote: > > @Mauricio: Thanks for the workaround to this "feature" ;-) > > > > @Marek: Thanks for the explanation. > > > > Is it a feature I can deactivate? My problem is the following: I want to > > plot something in the x-y-plane, using polar coordinates, so having a > > minus sign would be very nice. > > > > Cheers, > > Johannes Rauh > > > > > It's not an error, it's a feature. The numbers you read are NOT > > > y-values - you're plotting in polar coordinate system, aren't you? > > > So, what you see, is a set of r-values, and those are non-negative. > > > > > > Cheers, > > > Marek Gutowski > > > > > > Johannes Rauh wrote: > > > > Hello, > > > > > > > > I have a problem with gnuplot: When I do a polar plot, like e.g. > > > > > > > > set polar > > > > plot cos(t) > > > > > > > > the minus signs are missing on the axis, so the labels at the y-axis go > > > > 0.5 0.4 0.3 0.2 0.1 0 0.1 0.2 0.3 0.4 0.5 > > > > > > > > Any i! deas? > > > > Kind regards, > > > > > > > > Johannes Rauh > > > -- > Marek W. Gutowski > Institute of Physics, ON-3.2, Al. Lotnikow 32/46 > 02-668 Warszawa, POLAND, tel. +48-22-0228436601 ext. 3122 > == To talk or not to talk? Yes, talk, plain ASCII please == > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |