Re: [Matplotlib-users] Change Hue-Range in HSV color map
KarlBlau mailsgetl...@web.de writes:
I would like to change the hue range of the hsv color map to use only hue
values between 0 and 0.6667. I checked the documentation of matplotlib and
searched in the internet but couldn't find the answer.
There doesn't seem to be any predefined functionality for this. The
easiest way to achieve this is probably just to take the definition of
hsv from _cm.py and modify it a little:
data = {'red': ((0., 1., 1.),(0.158730, 1.00, 1.00),
(0.174603, 0.968750, 0.968750),(0.33, 0.031250, 0.031250),
(0.349206, 0.00, 0.00),(0.67, 0.00,
0.00)),
'green': ((0., 0., 0.),(0.158730, 0.937500, 0.937500),
(0.174603, 1.00, 1.00),(0.507937, 1.00, 1.00),
(0.67, 0.062500, 0.062500)),
'blue': ((0., 0., 0.),(0.33, 0.00, 0.00),
(0.349206, 0.062500, 0.062500),(0.507937, 1.00, 1.00),
(0.67, 1.00, 1.00))}
for k,v in data.items():
data[k] = [(a/0.67, b, c) for (a,b,c) in v]
myhsv = matplotlib.colors.LinearSegmentedColormap('myhsv', data)
--
Jouni K. Seppänen
http://www.iki.fi/jks
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[Matplotlib-users] ticks in Matplotlib
Hi, I'm looking into customizing the the tick positions on an imshow plot. I found that you can do this by doing img = imshow(data) img.ax.xaxis.set_ticks([100.,200.]) The problem with this method is that it moves the tick positions on the bottom and top x axis. What if I wanted to do have the top axes show ticks at slightly different positions than the bottom one? Any ideas or suggestions would be greatly appreciated -Eli -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] [matplotlib-devel] What would you like to see in a book about Matplotlib?
Hi Chris, thanks for your reply, helpful as usual :) On Fri, Jan 30, 2009 at 18:59, Chris Walker chr...@chiark.greenend.org.uk wrote: Firstly, good luck with the book. cheers :) The sort of book I'd buy would explain how to use the combination of matplotlib/ipython/scipy/numpy to analyse data. Sadly, that would not the book I'll write :( The editor wanted to target another audience for the book: experienced python developers, with no knowledge of matplotlib; so an introductionary book, that will show even how to integrate mpl on GTK/WX application and on the web. I pushed to have something about science, and a chapter will be about that, but I need your (all) inputs, because my science days are long back in the past ;) - what are the (basic) things that, when you were beginning to use matplotlib, you wanted to see grouped up but couldn't find? - what would you like to see in a book about matplotlib? Start off by reading data from a file, plotting it and fitting a function to that data. That sounds something that could land in the science chapter. Plotting with related scales Sometimes it is useful to plot related scales on x1 and x2 axes. I've come across this several times in different contexts. In its simplest form, there is a linear relationship between the axes. In a mechanical test, you might want extension on the x1 axis and strain on the x2 axis (for example). Sometimes there is not a linear relationship. For example you might want to plot frequency (or photon energy) on x1 and wavelength on x2. An even more complex example is a Hall-Petch plot: (Yield Stress) = k/sqrt(Grain Size) So plotting 1/Sqrt(Grain Size) on the X1 axis gives a linear plot, but it would be useful to plot the grain size on the X2 scale. Err, I think I lost you ;) What you want is 2 plots on the same figure? so not 2 Ys for the same X (let's say X is time, and Y1 is stock price variation, and Y2 is the percentage change), you want X1-Y1 (let's say on the bottom-left) and X2-Y2 (on the upper-right): did I get you? ipython and emacs - Suppose I want to write a script to analyse some data (perhaps I want a record of what I've done, or perhaps I'd like to perform the same analysis on several data sets). I'd probably do so in emacs - but it is useful to do some experimentation in ipython - tab completion is particularly useful. I feel there must be a good way to do my experimentation in ipython and save the important bits in emacs - but I've not sat down and worked out an efficient way of doing this. I think the preferred way to do so it using ipython, and for now I plan only to show it on the book. Data aqcuisition and experimental control: - Writing a simple application to acquire data - ideally from multiple sources and plot the data as it is acquired. In my case I wanted to combine mechanical with electrical tests. A couple of interesting articles by G Varoquaux are listed at http://wiki.debian.org/DebianScience/DataAcquisition This is perhaps beyond the scope of the book, but it has come up on the mailing lists a couple of times. The ideal application would have a gui for simple use, but a command line (probably ipython) for more more complex use - perhaps performing a series of tests under different conditions. I thought about an example for this already! :) I thought to develop a sample application for GTK/WX that display some system value (like cpu usage or so, in this way everyone can run the example) plotting the information as it comes (for 30 secs, for example). Some discussion of plotting non gridded 2d data should also be in there. for example? Your suggestions are really appreciated :) And wish me good luck! I don't think it is the thrust of your book, but another book I was looking for is A cookbook of Numerical simulations of classic physics/engineering problems. For use by physicists/engineers who don't want to rewrite things from scratch. As said, even if my degree is in linear algebra, my science days are gone, so it won't be in the book, if not for that chapter about science and mpl. Good luck. Cheers, -- Sandro Tosi (aka morph, morpheus, matrixhasu) My website: http://matrixhasu.altervista.org/ Me at Debian: http://wiki.debian.org/SandroTosi -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] ticks in Matplotlib
You cannot set different tick positions for bottom and top x-axis in the same axes. What you can do is to make another axes at the same location and use it to draw ticks at top. Take a look at http://matplotlib.sourceforge.net/examples/api/two_scales.html But it may not be an ideal solution for you as this enforces adjustable=datalim. You may try to use my custom axes class. http://dl.getdropbox.com/u/178748/mpl/parasite_axes2.py import matplotlib.pyplot as plt import numpy as np from parasite_axes2 import SubplotHost fig = plt.gcf() ax = SubplotHost(fig, 1, 1, 1) fig.add_subplot(ax) Z = np.arange(100).reshape(10,10) im = ax.imshow(Z) ax2 = ax.twin() ax2.set_xticks([0, 3, 6, 9]) ax2.set_yticks([1,3,5,7,9]) plt.draw() plt.show() Note that it enforces that ax2 has a same viewlim as the original axes. You cannot manually change it. -JJ On Sun, Feb 1, 2009 at 12:41 PM, Eli Bressert bress...@head.cfa.harvard.edu wrote: Hi, I'm looking into customizing the the tick positions on an imshow plot. I found that you can do this by doing img = imshow(data) img.ax.xaxis.set_ticks([100.,200.]) The problem with this method is that it moves the tick positions on the bottom and top x axis. What if I wanted to do have the top axes show ticks at slightly different positions than the bottom one? Any ideas or suggestions would be greatly appreciated -Eli -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
