matplotlib-users Mailing List for matplotlib (Page 15)

Mauro Cavalcanti wrote:
> Dear Jeff,
>
> Thanks for your fast reply. Unfortunately, I have not been able to get
> yet working:
>
> I have a menu event like this:
>
> borders = []
> if self.MapDrawBorderItem.IsChecked():
> 	borders = self.map.drawcountries()
> else:
> 	self.ax.lines.remove(borders)
>        # .... redraw the map here...
>
> But I got a ValueError: list.remove(x): x not in list
>
> Any hints?
>   

Mauro:  Instead of

self.ax.lines.remove(borders)

I think should simply do

borders.remove()

-Jeff
> With best regards,
>
> 2008/12/5 Jeff Whitaker <js...@fa...>:
>   
>> Mauro Cavalcanti wrote:
>>     
>>> Dear ALL,
>>>
>>> Always engaged in pushing MPL/Basemap ahead of its limits, here am I
>>> again with a humble question: I want to be able to toggle the display
>>> of country boundaries on a map using a menu option on my wxPython
>>> interface. It is quite easy to initially plotting a map without
>>> borders and then toggling them on, but I could not figure out a way to
>>> toggling them off (if possible, without redrawing the whole map). Is
>>> there any trick to do this? ;-)
>>>
>>> Thanks in advance!
>>>
>>> With warmest regards,
>>>
>>>
>>>       
>> Mauro:
>>
>> The drawcountries() method returns a matplotlib line collection.  Invoking
>> the remove() method of the line collection will remove the countries from
>> the axes instance.
>>
>> -Jeff
>>
>> --
>> Jeffrey S. Whitaker         Phone  : (303)497-6313
>> Meteorologist               FAX    : (303)497-6449
>> NOAA/OAR/PSD  R/PSD1        Email  : Jef...@no...
>> 325 Broadway                Office : Skaggs Research Cntr 1D-113
>> Boulder, CO, USA 80303-3328 Web    : http://tinyurl.com/5telg
>>
>>
>>     
>
>
>
>   


-- 
Jeffrey S. Whitaker         Phone  : (303)497-6313
Meteorologist               FAX    : (303)497-6449
NOAA/OAR/PSD  R/PSD1        Email  : Jef...@no...
325 Broadway                Office : Skaggs Research Cntr 1D-113
Boulder, CO, USA 80303-3328 Web    : http://tinyurl.com/5telg

Mauro Cavalcanti wrote:
> Dear ALL,
>
> Always engaged in pushing MPL/Basemap ahead of its limits, here am I
> again with a humble question: I want to be able to toggle the display
> of country boundaries on a map using a menu option on my wxPython
> interface. It is quite easy to initially plotting a map without
> borders and then toggling them on, but I could not figure out a way to
> toggling them off (if possible, without redrawing the whole map). Is
> there any trick to do this? ;-)
>
> Thanks in advance!
>
> With warmest regards,
>
>   

Mauro:

The drawcountries() method returns a matplotlib line collection.  
Invoking the remove() method of the line collection will remove the 
countries from the axes instance.

-Jeff

-- 
Jeffrey S. Whitaker         Phone  : (303)497-6313
Meteorologist               FAX    : (303)497-6449
NOAA/OAR/PSD  R/PSD1        Email  : Jef...@no...
325 Broadway                Office : Skaggs Research Cntr 1D-113
Boulder, CO, USA 80303-3328 Web    : http://tinyurl.com/5telg

Dear ALL,

Always engaged in pushing MPL/Basemap ahead of its limits, here am I
again with a humble question: I want to be able to toggle the display
of country boundaries on a map using a menu option on my wxPython
interface. It is quite easy to initially plotting a map without
borders and then toggling them on, but I could not figure out a way to
toggling them off (if possible, without redrawing the whole map). Is
there any trick to do this? ;-)

Thanks in advance!

With warmest regards,

-- 
Dr. Mauro J. Cavalcanti
Ecoinformatics Studio
P.O. Box 46521, CEP 20551-970
Rio de Janeiro, RJ, BRASIL
E-mail: mau...@gm...
Web: http://studio.infobio.net
Linux Registered User #473524 * Ubuntu User #22717
"Life is complex. It consists of real and imaginary parts."

The bottleneck for Python 3 adoption is going to be the availability of
compatible third party libraries. I'm using numpy, scipy, matplotlib,
wxpython, pywin32 and py2exe, so I'm not even going to download python 3
until all these projects have moved to it.

Armando.

On Fri, Dec 5, 2008 at 2:37 AM, Kaushik Ghose <Kau...@hm...
> wrote:

>
> Has anyone switched to python 3?
>
> Thanks
> -Kaushik
>

On Thu, Dec 4, 2008 at 8:42 PM, David Cournapeau
<da...@ar...> wrote:

>> Quick question. Is matplotlib python 3 compatible? Has anyone switched to python
>> 3? Anecdotally, how much of a pain is it to switch over, if you use common
>> scientific libraries such as PIL and VTK?
>>
>
> matplotlib depends on numpy, and numpy on python 3 won't be finished
> anytime soon - it will be a huge task.

mpl also depends on CXX for extension code.  I was heartened to see
that the python 3 migration is well underway in CXX svn.  Since this
is most of our extension code, hopefully it will insulate from serious
difficulties porting the extension code.  But we will have to wait for
CXX and numpy before we can do serious work.

JDH

Kaushik Ghose wrote:
> Hi Everyone,
>
> Quick question. Is matplotlib python 3 compatible? Has anyone switched to python 
> 3? Anecdotally, how much of a pain is it to switch over, if you use common 
> scientific libraries such as PIL and VTK?
>   

matplotlib depends on numpy, and numpy on python 3 won't be finished
anytime soon - it will be a huge task.

David

Hi Everyone,

Quick question. Is matplotlib python 3 compatible? Has anyone switched to python 
3? Anecdotally, how much of a pain is it to switch over, if you use common 
scientific libraries such as PIL and VTK?

Thanks
-Kaushik

Elfnor wrote:
> I'm giving an introductory talk on matplotlib to colleagues next week. I'd
> like to run matplotlib in interactive mode from the PythonWin IDE. Is this
> possible?

probably not reliably -- pythonWin IDE runs things inside the same 
interpreter as the IDE itself, and therefore has problems running GUI 
code with any GUI that MPL supports.

IPython has smarts to start up MPL in another thread to avoid the issues.

Has pythonWin IDE seen any maintenance in the last five years? It may be 
time for them to move on!

On the other hand, you can still edit code with the IDE, and start it 
from a command line.

-Chris



-- 
Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R            (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chr...@no...

Hi

I'm giving an introductory talk on matplotlib to colleagues next week. I'd
like to run matplotlib in interactive mode from the PythonWin IDE. Is this
possible?

I use PyScripter or occasionally IPython myself, but the python group I'm
talking to have all been set up with PythonWin and my brief is to avoid
confusing then with another IDE.

thanks Eleanor
-- 
View this message in context: http://www.nabble.com/Can-matplotlib-be-run-from-PythonWin-IDE-in-interactive-mode--tp20822638p20822638.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

Mike Hearne wrote:
> 
>  >>I don't think this is going to make it easy to do what you want
> 
> It might if I could find the x,y data in the LineCollection objects. 
>  There is an undocumented function in the LineCollection class called 
> get_paths(), which looks like it returns a list of Path objects.  These 
> path objects have a vertices property which looks like the stuff I want. 
>  I'll explore this for a while.  Anyone who knows more about these 
> objects, feel free to chime in!

Mike,

Have you tried simply making two sets of contours, one where you have 
masked out the region that you want dashed, and a second with the 
inverse of that mask?  (Or, maybe the original mask and the inverted 
mask should overlap so that the contours in both regions go to their 
common boundary.)  Granted, there may be edge effects between the 
regions, but it should be simple and quick.

Eric

> 
> Thanks,
> 
> Mike
> 
> 
> *Eric Firing <ef...@ha...>*
> 
> 12/03/08 01:59 PM
> 
> 	
> To
> 	Mike Hearne <mh...@us...>
> cc
> 	mat...@li...
> Subject
> 	Re: [Matplotlib-users] Contour line data
> 
> 
> 	
> 
> 
> 
> 
> 
> Mike Hearne wrote:
>  >
>  > How can I get the actual x,y data that represents the contour lines that
>  > are drawn with the contour() function?
>  >
>  > I'd like to be able to redraw portions of those lines with different
>  > styles (dashed, dotted, etc.)
>  >
>  > For example, given the following sample code (lifted from the
>  > sourceforge example):
>  >
>  > from pylab import *
>  > from numpy import *
>  >
>  > delta = 0.025
>  > x = arange(-3.0, 3.0, delta)
>  > y = arange(-2.0, 2.0, delta)
>  > X, Y = meshgrid(x, y)
>  > Z1 = bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)
>  > Z2 = bivariate_normal(X, Y, 1.5, 0.5, 1, 1)
>  > # difference of Gaussians
>  > Z = 10.0 * (Z2 - Z1)
>  > figure()
>  > cs = plt.contour(X, Y, Z)
>  > show()
>  >
>  > How could I, for example, re-draw the lines in the region X [0 1] Y
>  > [-1.5 -0.5] as dashed?
>  >
>  > I could do it, I think, if I had the for all the lines in the plot.
> 
> I don't think this is going to make it easy to do what you want, but
> cs.collections is a list of LineCollection objects corresponding to the
> contour levels in cs.levels.
> 
> Eric
> 

>>I don't think this is going to make it easy to do what you want

It might if I could find the x,y data in the LineCollection objects. There 
is an undocumented function in the LineCollection class called 
get_paths(), which looks like it returns a list of Path objects.  These 
path objects have a vertices property which looks like the stuff I want. 
I'll explore this for a while.  Anyone who knows more about these objects, 
feel free to chime in!

Thanks,

Mike



Eric Firing <ef...@ha...> 
12/03/08 01:59 PM

To
Mike Hearne <mh...@us...>
cc
mat...@li...
Subject
Re: [Matplotlib-users] Contour line data






Mike Hearne wrote:
> 
> How can I get the actual x,y data that represents the contour lines that 

> are drawn with the contour() function?
> 
> I'd like to be able to redraw portions of those lines with different 
> styles (dashed, dotted, etc.)
> 
> For example, given the following sample code (lifted from the 
> sourceforge example):
> 
> from pylab import *
> from numpy import *
> 
> delta = 0.025
> x = arange(-3.0, 3.0, delta)
> y = arange(-2.0, 2.0, delta)
> X, Y = meshgrid(x, y)
> Z1 = bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)
> Z2 = bivariate_normal(X, Y, 1.5, 0.5, 1, 1)
> # difference of Gaussians
> Z = 10.0 * (Z2 - Z1)
> figure()
> cs = plt.contour(X, Y, Z)
> show()
> 
> How could I, for example, re-draw the lines in the region X [0 1] Y 
> [-1.5 -0.5] as dashed?
> 
> I could do it, I think, if I had the for all the lines in the plot.

I don't think this is going to make it easy to do what you want, but 
cs.collections is a list of LineCollection objects corresponding to the 
contour levels in cs.levels.

Eric

Mike Hearne wrote:
> 
> How can I get the actual x,y data that represents the contour lines that 
> are drawn with the contour() function?
> 
> I'd like to be able to redraw portions of those lines with different 
> styles (dashed, dotted, etc.)
> 
> For example, given the following sample code (lifted from the 
> sourceforge example):
> 
> from pylab import *
> from numpy import *
> 
> delta = 0.025
> x = arange(-3.0, 3.0, delta)
> y = arange(-2.0, 2.0, delta)
> X, Y = meshgrid(x, y)
> Z1 = bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)
> Z2 = bivariate_normal(X, Y, 1.5, 0.5, 1, 1)
> # difference of Gaussians
> Z = 10.0 * (Z2 - Z1)
> figure()
> cs = plt.contour(X, Y, Z)
> show()
> 
> How could I, for example, re-draw the lines in the region X [0 1] Y 
> [-1.5 -0.5] as dashed?
> 
> I could do it, I think, if I had the for all the lines in the plot.

I don't think this is going to make it easy to do what you want, but 
cs.collections is a list of LineCollection objects corresponding to the 
contour levels in cs.levels.

Eric

How can I get the actual x,y data that represents the contour lines that 
are drawn with the contour() function?

I'd like to be able to redraw portions of those lines with different 
styles (dashed, dotted, etc.)

For example, given the following sample code (lifted from the sourceforge 
example):

from pylab import *
from numpy import *

delta = 0.025
x = arange(-3.0, 3.0, delta)
y = arange(-2.0, 2.0, delta)
X, Y = meshgrid(x, y)
Z1 = bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)
Z2 = bivariate_normal(X, Y, 1.5, 0.5, 1, 1)
# difference of Gaussians
Z = 10.0 * (Z2 - Z1)
figure()
cs = plt.contour(X, Y, Z)
show()

How could I, for example, re-draw the lines in the region X [0 1] Y [-1.5 
-0.5] as dashed?

I could do it, I think, if I had the for all the lines in the plot.

--Mike 

On Wed, Dec 3, 2008 at 9:15 AM, Nitin Bhide <nit...@ya...> wrote:
> Hi,
>
> I am getting following error while running the 'legend_demo3.py' from the examples.
>
> exec codeObject in __main__.__dict__
>  File "D:\nitinb\SoftwareSources\SVNPlot\legendtest.py", line 13, in <module>
>    ax1.legend(loc=1, ncol=3, shadow=True)
>  File "F:\Python25\Lib\site-packages\matplotlib\axes.py", line 3617, in legend
>    self.legend_ = mlegend.Legend(self, handles, labels, **kwargs)
> TypeError: __init__() got an unexpected keyword argument 'ncol'
>
> I am using ActivePython version 2.5.2 and Matplotlib version 0.98.3

We use the svn version of matplotlib to generate the website, and ncol
is a recent feature not in the main release yet.  You can checkout the
svn code following the instructions at
http://matplotlib.sourceforge.net/devel/coding_guide.html

I have added a note on the gallery warning people that not all the
images are available in the latest release with a pointer to the svn
instructions.

But we would like to get a release out ASAP!

JDH

Hi,

I am getting following error while running the 'legend_demo3.py' from the examples.

exec codeObject in __main__.__dict__
  File "D:\nitinb\SoftwareSources\SVNPlot\legendtest.py", line 13, in <module>
    ax1.legend(loc=1, ncol=3, shadow=True)
  File "F:\Python25\Lib\site-packages\matplotlib\axes.py", line 3617, in legend
    self.legend_ = mlegend.Legend(self, handles, labels, **kwargs)
TypeError: __init__() got an unexpected keyword argument 'ncol'

I am using ActivePython version 2.5.2 and Matplotlib version 0.98.3

Regards
Nitin



      

Nils Wagner wrote:
> Hi all,
> 
> How can I suppress xticks in a polar plot ?

import matplotlib.pyplot as plt
from matplotlib.ticker import NullFormatter

ax = plt.subplot(1, 1, 1, polar=True)
ax.xaxis.set_major_formatter(NullFormatter())
plt.show()

Ryan

-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma

Aleš Čadež wrote:
>
> Dear Jeffrey,
>
> First of all, sorry to bother you. I'm using matplotlib mapping 
> toolkit. Can you help me with one problem. I would like to colour 
> different countries with different colors. Is there any way to do this 
> with basemap toolkit library? I just can't seem to find any function 
> that would do that.
>
>  
>
> Thank you again,
>
> Ales Cadez
>
Ales:  You need an external shapefile containing country polygons for 
this.  The built-in country dataset in Basemap is made up of line 
segments, so you can't fill them.  Here's a simple example to get you 
started:

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.basemap import Basemap as Basemap
from matplotlib.patches import Polygon

# Robinson world map
m = Basemap(projection='robin',lon_0=0)
# draw country boundaries
# data from http://www.cipotato.org/diva/data/misc/world_adm0.zip
shp_info = m.readshapefile('world_adm0','countries',drawbounds=True)
ax = plt.gca() # get current axes instance
# fill US blue, Russia red, the rest gray.
for nshape,seg in enumerate(m.countries):
    if m.countries_info[nshape]['NAME'] == 'United States':
        poly = Polygon(seg,facecolor='b',edgecolor='b')
    elif m.countries_info[nshape]['NAME'] == 'Russia':
        poly = Polygon(seg,facecolor='r',edgecolor='r')
    else:
        poly = Polygon(seg,facecolor='0.7',edgecolor='0.7')
    ax.add_patch(poly)
# draw meridians and parallels.
m.drawparallels(np.arange(-80,81,20))
m.drawmeridians(np.arange(-180,180,60))
# draw projection limb, set background color
m.drawmapboundary(fill_color='aqua')
plt.title('US Blue, Russia Red')
plt.show()


-Jeff

-- 
Jeffrey S. Whitaker         Phone : (303)497-6313
NOAA/OAR/CDC  R/PSD1        FAX   : (303)497-6449
325 Broadway                Boulder, CO, USA 80305-3328

Hi all,

How can I suppress xticks in a polar plot ?

Nils
  

Thank you for your answers and the obvious solution (banging head into wall).

Best regards,
Jesper

2008/12/1 Jae-Joon Lee <lee...@gm...>:
> On Mon, Dec 1, 2008 at 12:56 AM, Jesper Larsen <jes...@gm...> wrote:
>> Hi Matplotlib users,
>>
>> I have a web application in which I would like to scale the plots down
>> if the users horizontal screen size is less than 800. Currently only
>> the plot is scaled while the fonts are fixed in size (see link below
>> for application). This is of course not a viable solution. I was
>> therefore wondering what the best way to scale fonts consistently with
>> figure size is. A requirement is that the scaling is thread safe (or
>> whatever it is called) in the sense that it should not affect other
>> threads executing matplotlib (since they may have different screen
>> resolutions).
>>
>
> Saving the figure with smaller dpi doesn't work?
> It is not clear how you're scaling down the over all plot (smaller
> figure size, maybe?),
> but I guess the easiest way is to have everything same and save it
> with a smaller dpi.
>
> -JJ
>

João et al.,

Thanks for the bug report.  Mike D. has fixed the problem in svn. (I had 
moved the discussion to matplotlib-devel; I am just reporting back to 
matplotlib-users so this thread can be closed.)

Eric

Eric Firing wrote:
> wafels wrote:
>> Hello,
>>
>> I can confirm and extend this bug report.  The axvline also moves to the
>> wrong position on resizing the matplotlib display window (Mac OS X 10.5.5,
>> Python 2.5.1, Matplotlib 0.98.3).
>>
>> Thanks
> 
> It looks like the transform for the line made by axvline is not getting 
> updated when view limits change.  The problem is found in svn, after the 
> changes I made to axvline, as well as in 0.98.3.  I can't track it down 
> right now.
> 
> Eric
> 
>>
>>
>> João Luís Silva-2 wrote:
>>> Hi,
>>>
>>> A vertical line on the x axis of a semilogy plot will be in the correct 
>>> position, but when saved with the save button of the toolbar it will be 
>>> placed in an incorrect position, although savefig will do the right 
>>> thing. Furthermore, zooming will not move the axvline correctly.
>>>
>>> Matplotlib version: 0.98.3
>>>
>>> Example script:
>>> -----------------------------------------
>>>
>>> import matplotlib.pyplot as pl
>>> import numpy as np
>>>
>>> x = np.linspace(0.0,1.0,100)
>>>
>>> pl.semilogy(x,x**2)
>>> pl.axvline(x=0.5,ls='--',color='k')
>>> pl.show()
>>> #pl.savefig("saved_image.png")
>>> -----------------------------------------
>>>
>>> image.png was saved using the toolbar, saved_image.png using savefig.
>>>
>>> Regards,
>>> João Silva

Thanks for the rapid fix Mike.

regards,
Gary

Michael Droettboom wrote:
> There is an explicit offset of one pixel on the left when it sets up a 
> clip box in Agg.  I don't know why this is there, but it dates back to 
> 0.98.0, and earlier versions did something completely different.  I can 
> only guess it was to compensate for an earlier bug in the precise 
> drawing of the axes rectangle.  I can't explain why it would have 
> different behavior on Windows vs. Linux, though.
> 
> I have fixed this in SVN r6465 and am including a patch below (which 
> unfortunately requires a recompile).
> 
> Cheers,
> Mike

I've committed both of these things.  The subplot()/polar() change seems 
tricky, so it may produce some breakage even though the "regression 
tests" are passing.  Please let me know if you see anything strange 
after this change.

Mike

Ryan May wrote:
> Michael Droettboom wrote:
>> Thanks for updating the docstring.  I actually saw this as a 
>> usability bug and have come up with a patch such that polar() (et al) 
>> will *replace* the current axes with a polar plot if it isn't already 
>> polar.  This is (from the user's perspective) similar to how, for 
>> example, a histogram plot would work -- that is, you don't have to 
>> tell subplot you're about to plot a histogram.
>>
>> But Ryan's new docstring is not obsolete with respect to my proposed 
>> change.  Both techniques will work, and in fact subplot(polar=True); 
>> polar(...) will be slightly faster since it avoids creating a linear 
>> axes which is subsequently thrown away.
>>
>> Any argument against committing my change?
>
> None here.  I'm +1.
>
>> The polar theta tick formatter could be changed to call "round", I 
>> guess.  Alternatively, it looks like '%0.0f' also does the right 
>> thing.  I think that's generally what people would want for polar 
>> plots.  This change would only affect polar theta ticks, so we don't 
>> need to worry about a change in behavior in standard Euclidean plots.
>>
>> Ryan's workaround (to get around this numerically external to 
>> matplotlib) is a good suggestion as well, but I think changing the 
>> formatter may be less surprising...
>
> I like the idea of using %0.0f.  If I don't hear any objections, I'll 
> go ahead and make the change.  It definitely will make things less 
> confusing for our users.
>
> Ryan
>

-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Michael Droettboom wrote:
> Thanks for updating the docstring.  I actually saw this as a usability 
> bug and have come up with a patch such that polar() (et al) will 
> *replace* the current axes with a polar plot if it isn't already polar.  
> This is (from the user's perspective) similar to how, for example, a 
> histogram plot would work -- that is, you don't have to tell subplot 
> you're about to plot a histogram.
> 
> But Ryan's new docstring is not obsolete with respect to my proposed 
> change.  Both techniques will work, and in fact subplot(polar=True); 
> polar(...) will be slightly faster since it avoids creating a linear 
> axes which is subsequently thrown away.
> 
> Any argument against committing my change?

None here.  I'm +1.

> The polar theta tick formatter could be changed to call "round", I 
> guess.  Alternatively, it looks like '%0.0f' also does the right thing.  
> I think that's generally what people would want for polar plots.  This 
> change would only affect polar theta ticks, so we don't need to worry 
> about a change in behavior in standard Euclidean plots.
> 
> Ryan's workaround (to get around this numerically external to 
> matplotlib) is a good suggestion as well, but I think changing the 
> formatter may be less surprising...

I like the idea of using %0.0f.  If I don't hear any objections, I'll go 
ahead and make the change.  It definitely will make things less 
confusing for our users.

Ryan

-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma

On Tue, Dec 2, 2008 at 12:09 PM, Eric Emsellem
<ems...@ob...> wrote:

> Really annoying but as mentioned before, I cannot get a set of commands which
> consistenly break the session, so...

Since there does not appear to be an easy diagnosis or fix, you may
want to consider switching your backend to the non-threaded tkagg

JDH

Ryan May wrote:
> On Tue, Dec 2, 2008 at 11:27 AM, Nils Wagner 
> <nw...@ia... <mailto:nw...@ia...>> 
> wrote:
>
>     Thank you very much !
>     It would be nice to have that information in the docstring
>
>
> Done.
Thanks for updating the docstring.  I actually saw this as a usability 
bug and have come up with a patch such that polar() (et al) will 
*replace* the current axes with a polar plot if it isn't already polar.  
This is (from the user's perspective) similar to how, for example, a 
histogram plot would work -- that is, you don't have to tell subplot 
you're about to plot a histogram.

But Ryan's new docstring is not obsolete with respect to my proposed 
change.  Both techniques will work, and in fact subplot(polar=True); 
polar(...) will be slightly faster since it avoids creating a linear 
axes which is subsequently thrown away.

Any argument against committing my change?
>  
>
>     The next inquiry is related to xticks.
>     I have added
>
>     xticks(linspace(0,2*pi,24,endpoint=False))
>
>     The difference between consecutive xticks is varying between 14
>     and 16 degrees.
>
>     For what reason ?
>
>
> Looks like roundoff error.   For instance:
>
> linspace(0, 2*pi, 24)[7] * 180. / pi
> 104.999999999999
>
> If you format that with '%d', it becomes 104, not 105.
>
> Is there an accepted way of doing this rounding in matplotlib that 
> doesn't round in odd cases?
The polar theta tick formatter could be changed to call "round", I 
guess.  Alternatively, it looks like '%0.0f' also does the right thing.  
I think that's generally what people would want for polar plots.  This 
change would only affect polar theta ticks, so we don't need to worry 
about a change in behavior in standard Euclidean plots.

Ryan's workaround (to get around this numerically external to 
matplotlib) is a good suggestion as well, but I think changing the 
formatter may be less surprising...

Cheers,
Mike

-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA