matplotlib-users Mailing List for matplotlib

Thanks Ben
so streamplot "will" be part of a future stable release of matplotlib
then ? one does not need the scikits.vectorplot installed ?
I will try and pull the latest development version of matplotlib and
install it (linux and mac os X), and then come back to the list to
give some feedbacks
cheers
Nico
On 21 June 2012 11:37, Benjamin Root <ben...@ou...> wrote:
>
>
> On Wednesday, June 20, 2012, Nicolas wrote:
>>
>> Hi all
>>
>> I have installed successively basemap 1.0.3 and 1.0.4 on top of my EPD
>> 7.3 (linux x86_64) running on a linux ubuntu 11.10.
>>
>> archives downloaded from
>>
>> http://sourceforge.net/projects/matplotlib/files/matplotlib-toolkits/basemap-1.0.X/
>>
>> My matplotlib version is 1.1.0 and I have checked that indeed the call
>> to mpl_toolkits.basemap returns the correct version (I have installed
>> successively 1.0.3 and then cleaned up and installed 1.0.4)
>>
>> the traceback is
>>
>> """
>> Traceback (most recent call last):
>> File "streamplot_demo.py", line 32, in <module>
>>
>> m.streamplot(x,y,udat,vdat,color=speed,linewidth=2,density=2,cmap=plt.cm.spectral)
>> File
>> "/home/nicolasf/epd/lib/python2.7/site-packages/mpl_toolkits/basemap/__init__.py",
>> line 3370, in streamplot
>> ret = ax.streamplot(x,y,u,v,*args,**kwargs)
>> AttributeError: 'AxesSubplot' object has no attribute 'streamplot'
>> """
>>
>> the doc string for streamplot_demo.py (in the example folder of the
>> basemap1.0.4 sources) states that it requires the vectorplot scikit,
>> which I have installed but been unable to get working (complains about
>> missing lic_internal module ...)
>>
>> what is confusing is that the entry for streamplot_demo in the README
>> (from basemap_1.0.4-examples) states that it "shows the new matplotlib
>> streamplot method to visualize wind fields"
>>
>> Do I need to upgrade matplotlib to the development version ?
>
>
>
> Yes. Streamplot hasn't been officially released yet. Maybe Basemap should
> check for the function first?
>
> Ben Root
-- 
-------------------------------------------------------------------------------------
Dr. Nicolas Fauchereau
Climate Scientist – National Climate Centre
National Institute of Water and Atmospheric Research (NIWA) Ltd.
41 Market Place
Viaduct Precinct, Auckland
NEW ZEALAND
Tel: +64 (0)9 375 2053
--------------------------------------------------------------------------------------
"It is a mistake to think you can solve any major problems just with potatoes.".
Douglas Adams.

On Wednesday, June 20, 2012, Nicolas wrote:
> Hi all
>
> I have installed successively basemap 1.0.3 and 1.0.4 on top of my EPD
> 7.3 (linux x86_64) running on a linux ubuntu 11.10.
>
> archives downloaded from
>
> http://sourceforge.net/projects/matplotlib/files/matplotlib-toolkits/basemap-1.0.X/
>
> My matplotlib version is 1.1.0 and I have checked that indeed the call
> to mpl_toolkits.basemap returns the correct version (I have installed
> successively 1.0.3 and then cleaned up and installed 1.0.4)
>
> the traceback is
>
> """
> Traceback (most recent call last):
> File "streamplot_demo.py", line 32, in <module>
>
> m.streamplot(x,y,udat,vdat,color=speed,linewidth=2,density=2,cmap=plt.cm.spectral)
> File
> "/home/nicolasf/epd/lib/python2.7/site-packages/mpl_toolkits/basemap/__init__.py",
> line 3370, in streamplot
> ret = ax.streamplot(x,y,u,v,*args,**kwargs)
> AttributeError: 'AxesSubplot' object has no attribute 'streamplot'
> """
>
> the doc string for streamplot_demo.py (in the example folder of the
> basemap1.0.4 sources) states that it requires the vectorplot scikit,
> which I have installed but been unable to get working (complains about
> missing lic_internal module ...)
>
> what is confusing is that the entry for streamplot_demo in the README
> (from basemap_1.0.4-examples) states that it "shows the new matplotlib
> streamplot method to visualize wind fields"
>
> Do I need to upgrade matplotlib to the development version ?
Yes. Streamplot hasn't been officially released yet. Maybe Basemap should
check for the function first?
Ben Root

Hi all
I have installed successively basemap 1.0.3 and 1.0.4 on top of my EPD
7.3 (linux x86_64) running on a linux ubuntu 11.10.
archives downloaded from
http://sourceforge.net/projects/matplotlib/files/matplotlib-toolkits/basemap-1.0.X/
My matplotlib version is 1.1.0 and I have checked that indeed the call
to mpl_toolkits.basemap returns the correct version (I have installed
successively 1.0.3 and then cleaned up and installed 1.0.4)
the traceback is
"""
Traceback (most recent call last):
 File "streamplot_demo.py", line 32, in <module>
 m.streamplot(x,y,udat,vdat,color=speed,linewidth=2,density=2,cmap=plt.cm.spectral)
 File "/home/nicolasf/epd/lib/python2.7/site-packages/mpl_toolkits/basemap/__init__.py",
line 3370, in streamplot
 ret = ax.streamplot(x,y,u,v,*args,**kwargs)
AttributeError: 'AxesSubplot' object has no attribute 'streamplot'
"""
the doc string for streamplot_demo.py (in the example folder of the
basemap1.0.4 sources) states that it requires the vectorplot scikit,
which I have installed but been unable to get working (complains about
missing lic_internal module ...)
what is confusing is that the entry for streamplot_demo in the README
(from basemap_1.0.4-examples) states that it "shows the new matplotlib
streamplot method to visualize wind fields"
Do I need to upgrade matplotlib to the development version ?
thanks a lot in advance for any help on that one ...
-- 
-------------------------------------------------------------------------------------
Dr. Nicolas Fauchereau
Climate Scientist – National Climate Centre
National Institute of Water and Atmospheric Research (NIWA) Ltd.
41 Market Place
Viaduct Precinct, Auckland
NEW ZEALAND
Tel: +64 (0)9 375 2053
--------------------------------------------------------------------------------------
"It is a mistake to think you can solve any major problems just with potatoes.".
Douglas Adams.

On Tue, Mar 27, 2012 at 3:31 AM, Mike Kaufman <mc...@gm...> wrote:
> On 3/26/12 12:49 PM, Christopher Graves wrote:
>
>> On Sun, Mar 11, 2012 at 2:32 PM, Christopher Graves
>> <chr...@gm... <mailto:chr...@gm...>> wrote:
>>
>
> Try this:
>>
>> from pylab import *
>> from matplotlib.ticker import AutoMinorLocator
>>
>> clf()
>> ax=subplot(111)
>> ax.autoscale(tight=True)
>> plot([1,2,4],[1,2,3])
>> ax.xaxis.set_minor_locator(__AutoMinorLocator(2))
>> ax.yaxis.set_minor_locator(__AutoMinorLocator(2))
>>
>> draw()
>>
>> M
>>
>> PS: I believe this is a fairly new feature...
>>
>>
>> Thanks! Great news that AutoMinorLocator has been added and
>> accomplishes this. Regarding the P.S. I can confirm that the feature
>> was not in matplotlib 1.0.1 - I had to update to 1.1.0 to use it.
>>
>> Best /Chris
>>
>>
>>
>> Hi Mike,
>>
>> A follow-up question... When using that, if one then tries to manually
>> use the zoom-box tool available with a matplotlib plot, if one draws too
>> small of a box (less than 2 major ticks in x or y dimension, based on
>> the following error message), it gives the following error and further
>> operations on the plot do not work.
>>
>> ValueError: Need at least two major ticks to find minor tick locations
>> ( File "/usr/lib/pymodules/python2.7/matplotlib/ticker.py", line 1528,
>> in __call__ )
>>
>> Any way to avoid this for now? (And ultimately, should this be made into
>> a bug fix request?)
>>
>
>
> Ok, I seem to remember seeing this error before, but I can't trip it now
> (with either 1.1.1rc or today's git checkout of 1.2.x). Do you have
> a short script that can reproduce this? For me, the zoom-box tool seems to
> be [correctly] setting the majortick locations as I zoom in, thus
> preventing this exception. I should note that I'm using the GTKAgg
> frontend. This may be the issue. A long time ago I was using the MacOSX
> frontend, and maybe this was when I was seeing it...
>
> Aside from that, this would be a bug.
>
> M
>
On Wed, Mar 28, 2012 at 10:50 PM, Christopher Graves <
chr...@gm...> wrote:
> Hi Mike,
>
> Ok I found the root cause. Here is a short script:
>
>
> from pylab import *
>
> from matplotlib.ticker import MultipleLocator, AutoMinorLocator
>
> plot([0,3],[0,2.2])
>
> ax = gca()
>
> ax.xaxis.set_major_locator(MultipleLocator(0.5))
>
> ax.xaxis.set_minor_locator(AutoMinorLocator(2))
>
> show()
>
>
> Once MultipleLocator has been called, the auto-reassigning of tick spacing
> when zooming (either with the zoom box or the cross and right-click drag)
> does not happen, and then AutoMinorLocator has the error because it has
> "majorstep = majorlocs[1] - majorlocs[0]" and majorlocs has less than 2
> elements when zoomed in that far. (GTKAgg vs others doesn't matter.)
>
> Seems like a bug. Is it the same in the newer mpl version you have?
> For my purposes, a different fix could work, because my reason to use
> MultipleLocator is only to make x and y major ticks have equal spacing, as
> follows:
>
> from pylab import *
>
> from matplotlib.ticker import MultipleLocator, AutoMinorLocator
>
> ax = subplot(111, aspect='equal')
>
> plot([0,3],[0,1.1])
>
> # Set the ticks to have the same interval on both x and y axes:
>
> x_major_tick_interval =
> abs(ax.xaxis.get_ticklocs()[0]-ax.xaxis.get_ticklocs()[1])
>
> ax.yaxis.set_major_locator(MultipleLocator(x_major_tick_interval))
>
> # 2 minor ticks per major tick:
>
> ax.yaxis.set_minor_locator(AutoMinorLocator(2))
>
> ax.xaxis.set_minor_locator(AutoMinorLocator(2))
>
> show()
>
>
> aspect='equal' is not necessary to bring out the error, it just
> illustrates the purpose of this. Is there another way to fix the x and y
> tick interval as equal? (And ideally even maintain the equal spacing when
> zooming.. As it is, they initially show as equal, but when zooming they can
> lose equal visible spacing while maintaining equal value intervals.)
>
>
> Best,
>
> Chris
>
On Thu, Mar 29, 2012 at 4:06 AM, Mike Kaufman <mc...@gm...> wrote:
> I can confirm this bug on yesterday's checkout. About equal spacing, I
> don't know offhand. A question to ask the list I think. If you could,
> please file as an issue on the github tracker. Include your code nugget
> that reproduces. Thanks.
>
> I don't have a lot of time at this moment, so hopefully somebody else
> looks at fixing it first.
>
> M
>
On Thu, Mar 29, 2012 at 11:53 AM, Christopher Graves <
chr...@gm...> wrote:
>
> Ok, bug is filed at https://github.com/matplotlib/matplotlib/issues/807
>
Has anyone had a chance to take a look at this very annoying bug with using
AutoMinorLocator?
Best,
Chris

Hello,
Would like to understand the "best" way to animate / move text on an wxAgg
frame. The following demo code adds text to a random location for each
button interrupt. How best to change this code so that the text is added
only once, and then efficiently move this text to a new random location
for each button interrupt (using perhaps blit, without recreating the
canvas??)? If this has been answered before, please point me to the
thread. Thank you, Doug.
Code...
class MyNavigationToolbar(NavigationToolbar2WxAgg):
 ON_CUSTOM = wx.NewId()
 def __init__(self, canvas):
 NavigationToolbar2WxAgg.__init__(self, canvas)
 self.AddSimpleTool(self.ON_CUSTOM, _load_bitmap('stock_left.xpm'),
'Click me')
 wx.EVT_TOOL(self, self.ON_CUSTOM, self._on_custom)
 def _on_custom(self, evt):
 ax = self.canvas.figure.axes[0]
 x,y = tuple(np.random.rand(2))
 rgb = tuple(np.random.rand(3))
 ax.text(x, y, 'You clicked me', transform=ax.transAxes, color=rgb)
 self.canvas.draw()
 evt.Skip()
.
.
.
toolbar = MyNavigationToolbar(canvas)
toolbar.Realize()

The postscript output of the Cairo backend supports transparency 
emulation, though it hasn't been tested in some time. Eric's suggestion 
(to output PDF and then convert to EPS) is also a reasonable one.
Mike
On 06/20/2012 10:38 AM, Francesco Montesano wrote:
> Dear list,
>
> it might be that this is not the best place to ask, but I guess that
> there are enough people with experience with colors.
>
> I think plots with nice colors and shaded areas are very nice, but for
> my publication I have to use eps files, that do not support
> transparency.
> The script below produce a figure like the one that I would like to
> make. If I save it as eps all the shaded areas are not transparent and
> the plot look ugly and unreadable.
>
> A way to emulate transparency that I've applied some time ago was to
> get the RGB value of the transparent color (with DigitalColor Meter on
> Mac) and to insert it by hand in fill_between, with a low value for
> the zorder option. The results was fine, but I don't like too much
> this approach, as any change in color or alpha value would require to
> go, get the new color, insert it and redo the figure.
>
> Is anyone aware of a way to obtain automatically a RGB color that on
> screen or printed looks similar to the corresponding RGBA?
>
> Thanks in advance,
> Francesco
>
> ********Sample code*********
>
> "plot with errors done with fill_between. Emulation of alpha in eps"
>
> import itertools as it
> import matplotlib.pyplot as plt
> import numpy as np
>
> col = it.cycle([ 'm', 'r', 'g', 'b', 'c', 'y', 'k', ])
> ls = it.cycle( [ '-', '--', '-.', ':' ][::-1])
>
> #figure
> fig = plt.figure()
> ax = fig.add_subplot(111)
>
> x= np.linspace(0.5,5,100)
> for i in range(3):
> c = col.next()
> l = ls.next()
> ax.plot( x, np.sin(x)**i, color=c, ls=l,
> label='$sin^{0}(x)$'.format(i), zorder=10+i )
> ax.fill_between( x, np.sin(x)**i + 1./x, np.sin(x)**i - 1./x,
> color=c, linestyle=l, alpha=0.5, zorder=i+1)
>
> ax.legend(frameon=False)
>
> plt.savefig("test_alpha.pdf")
> plt.savefig("test_alpha.eps")
> plt.show()
>
> exit()
> ********End sample code*********
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

On 06/20/2012 04:38 AM, Francesco Montesano wrote:
> Dear list,
>
> it might be that this is not the best place to ask, but I guess that
> there are enough people with experience with colors.
>
> I think plots with nice colors and shaded areas are very nice, but for
> my publication I have to use eps files, that do not support
> transparency.
> The script below produce a figure like the one that I would like to
> make. If I save it as eps all the shaded areas are not transparent and
> the plot look ugly and unreadable.
>
> A way to emulate transparency that I've applied some time ago was to
> get the RGB value of the transparent color (with DigitalColor Meter on
> Mac) and to insert it by hand in fill_between, with a low value for
> the zorder option. The results was fine, but I don't like too much
> this approach, as any change in color or alpha value would require to
> go, get the new color, insert it and redo the figure.
>
> Is anyone aware of a way to obtain automatically a RGB color that on
> screen or printed looks similar to the corresponding RGBA?
>
> Thanks in advance,
> Francesco
Francesco,
Can't you achieve the same result more easily by saving as pdf and then 
using something like ghostscript to convert the pdf to eps?
Eric

Dear list,
it might be that this is not the best place to ask, but I guess that
there are enough people with experience with colors.
I think plots with nice colors and shaded areas are very nice, but for
my publication I have to use eps files, that do not support
transparency.
The script below produce a figure like the one that I would like to
make. If I save it as eps all the shaded areas are not transparent and
the plot look ugly and unreadable.
A way to emulate transparency that I've applied some time ago was to
get the RGB value of the transparent color (with DigitalColor Meter on
Mac) and to insert it by hand in fill_between, with a low value for
the zorder option. The results was fine, but I don't like too much
this approach, as any change in color or alpha value would require to
go, get the new color, insert it and redo the figure.
Is anyone aware of a way to obtain automatically a RGB color that on
screen or printed looks similar to the corresponding RGBA?
Thanks in advance,
Francesco
********Sample code*********
"plot with errors done with fill_between. Emulation of alpha in eps"
import itertools as it
import matplotlib.pyplot as plt
import numpy as np
col = it.cycle([ 'm', 'r', 'g', 'b', 'c', 'y', 'k', ])
ls = it.cycle( [ '-', '--', '-.', ':' ][::-1])
#figure
fig = plt.figure()
ax = fig.add_subplot(111)
x= np.linspace(0.5,5,100)
for i in range(3):
 c = col.next()
 l = ls.next()
 ax.plot( x, np.sin(x)**i, color=c, ls=l,
label='$sin^{0}(x)$'.format(i), zorder=10+i )
 ax.fill_between( x, np.sin(x)**i + 1./x, np.sin(x)**i - 1./x,
color=c, linestyle=l, alpha=0.5, zorder=i+1)
ax.legend(frameon=False)
plt.savefig("test_alpha.pdf")
plt.savefig("test_alpha.eps")
plt.show()
exit()
********End sample code*********

On Wed, Jun 20, 2012 at 6:12 AM, mogliii <mo...@gm...> wrote:
> Hi,
>
> on the computer where it does not work the backend is 'agg'. In a
> virtual machine, where it works, the backend shows 'TkAgg'
>
> Now on the machine it does not work I run the following:
>
> >>> import matplotlib
> >>> matplotlib.use('TkAgg')
> >>> import matplotlib.pyplot as plt
>
> ImportError: cannot import name _tkagg
>
>
> Works with 'QT4Agg' though. Where is the default config for matplotlib
> located so I can change to 'QT4Agg'?
>
> Many thanks so far. Plot window opened. But I don't want to set the
> backend everytime i run matplotlib.
>
>
Ah, this would mean that the Tk development files were not available (or in
a location to be found) when you built/installed matplotlib. When
libraries like these aren't found, matplotlib falls back to the Agg
backend, which can not display a window. To have QT4Agg as your default
backend, just edit your matplotlibrc file. You should see an entry for
"backend".
Cheers!
Ben Root

Hi,
on the computer where it does not work the backend is 'agg'. In a
virtual machine, where it works, the backend shows 'TkAgg'
Now on the machine it does not work I run the following:
>>> import matplotlib
>>> matplotlib.use('TkAgg')
>>> import matplotlib.pyplot as plt
ImportError: cannot import name _tkagg
Works with 'QT4Agg' though. Where is the default config for matplotlib
located so I can change to 'QT4Agg'?
Many thanks so far. Plot window opened. But I don't want to set the
backend everytime i run matplotlib.
On 19/06/2012 18:43, Goyo wrote:
> 2012年6月19日 Goyo <goy...@gm...>:
>>> I think it normally shouldn't give the object ID.
>> Yes, it should.
>>
> Sorry, not an "object ID" but a string representation of the returned object.
>

Hi André, 
Have you tried to run your script from within IPython? That is, run "ipython --pylab" in your Terminal and "%run your_script.py" inside IPython. This always keeps the figures around for me, regardless of the presence of show().
Good luck,
Ludwig