matplotlib-users Mailing List for matplotlib

Hi,

in this example:

========================================
import numpy as np
import matplotlib.pyplot as plt

arr = np.random.random((10, 10))

plt.contourf(arr, 10)
plt.contourf(arr, 10, cmap='coolwarm', levels=np.arange(0, 1, .2), alpha=.5)
plt.colorbar()
plt.show()
========================================

colorbar is representing last contour. 

I want to make colorbar that will match actual plot, which is combination of two contours obviously. I tried also something like:

========================================
import numpy as np
import matplotlib.pyplot as plt

arr = np.random.random((10, 10))

fig = plt.figure()
ax = fig.add_subplot(111)

cax = ax.contourf(arr, 10)
cb = fig.colorbar(cax)
cax = ax.contourf(arr, 10, cmap='coolwarm', levels=np.arange(0, 1, .2), alpha=.5)
cb.update_bruteforce(cax)    # tried also: cb.update_normal(cax)

plt.show()
========================================

but it didn't get me there. Is there some easy way to do this?

Thanks

Hi Paul,

I've modified your suggestion a little, since I don't want a grid for the
primary axis at all -- unfortunately to no avail, i.e. no grid line at all:

import numpy

import matplotlib

matplotlib.use('agg')

import matplotlib.pyplot as plt


datax = numpy.arange(50)

data1 = numpy.sin(datax)*1.5

data2 = datax**2


plt.close('all')


fig = plt.figure()

ax1 = fig.add_subplot(111)

ax2 = ax1.twinx()


ax1.plot(datax, data1, 'x')

ax2.plot(datax, data2, '--')


#for ax in [ax1, ax2]:

# ax.xaxis.grid(True, which='both') # `which` can be 'minor', 'major', or
'both'

# ax.yaxis.grid(True, which='both')


ax2.xaxis.grid(True, which='both')

ax2.yaxis.grid(True, which='both')


fig.savefig('twinxgrid.png')

#fig.show()

On Thu, Jun 13, 2013 at 4:47 AM, Daniel Mader <
dan...@go...> wrote:

> Hi,
>
> I need a twinx() plot with horizontal and vertical grid lines for the
> second axis, just like the usual grid for the first axis. I don't need or
> want to specify the ticks manually, though!
>
> My example code just produces horizontal lines:
>
> import pylab
>
>
> datax = pylab.arange(50)
>
> data1 = pylab.sin(datax)*1.5
>
> data2 = datax**2
>
>
> pylab.close('all')
>
>
> fig = pylab.figure()
>
> ax1 = fig.add_subplot(111)
>
> ax2 = ax1.twinx()
>
>
> ax1.plot(datax, data1, 'x')
>
> ax2.plot(datax, data2, '--')
>
>
> #ax1.grid()
>
> ax2.grid()
>
>
> fig.show()
>
>
> Thanks in advance!
>

Does this get you where you want to be?

import pylab

datax = pylab.arange(50)
data1 = pylab.sin(datax)*1.5
data2 = datax**2

pylab.close('all')

fig = pylab.figure()
ax1 = fig.add_subplot(111)
ax2 = ax1.twinx()

ax1.plot(datax, data1, 'x')
ax2.plot(datax, data2, '--')

for ax in [ax1, ax2]:
    ax.xaxis.grid(True, which='both') # `which` can be 'minor', 'major', or
'both'
    ax.yaxis.grid(True, which='both')

fig.show()

close_figures,  not close_all

Haven't tried to switch it at run time using %config magic though.

$ ipython [qtconsole|notebook|whatever] --help-all 

to get all option as examples in config files are **not** updated with IPython.

InlineBackend options
---------------------
--InlineBackend.close_figures=<CBool>
    Default: True
    Close all figures at the end of each cell.
    When True, ensures that each cell starts with no active figures, but it also
    means that one must keep track of references in order to edit or redraw
    figures in subsequent cells. This mode is ideal for the notebook, where
    residual plots from other cells might be surprising.
    When False, one must call figure() to create new figures. This means that
    gcf() and getfigs() can reference figures created in other cells, and the
    active figure can continue to be edited with pylab/pyplot methods that
    reference the current active figure. This mode facilitates iterative editing
    of figures, and behaves most consistently with other matplotlib backends,
    but figure barriers between cells must be explicit.

savefig works for me when I put both the plotting commands and the savefig
call in the *same* code cell.


On Thu, Jun 13, 2013 at 10:31 AM, Sudheer Joseph
<sud...@ya...>wrote:

> Thank you,
> I don't see a way other than starting in normal mode as the moment I type
> plot command it get displayed and I don't need to do a show command.
> With best regards sudheer
>
>  ------------------------------
> * From: * Paul Hobson <pmh...@gm...>;
> * To: * Sudheer Joseph <sud...@ya...>;
> * Cc: * mat...@li... <
> mat...@li...>;
> * Subject: * Re: [Matplotlib-users] savefig
> * Sent: * Thu, Jun 13, 2013 2:23:05 PM
>
>
> On Wed, Jun 12, 2013 at 10:28 PM, Sudheer Joseph <sud...@ya...
> > wrote:
>
>> Dear experts,
>> I start ipython in ipython qtconsole --pylab=inline mode and make a plot.
>> But if I use savefig('fig.png') the figure do not get saved instead I get a
>> blank page.
>>
>>  I also tried img.save('fig.png',png) but no use. Is there a way out or I
>> need to do this after quitting and restarting in normal mode each time I
>> want to save?
>>
>> ipython qtconsole --pylab=inline
>>
>>
>> In [93]: ts.plot()
>> Out[93]: <matplotlib.axes.AxesSubplot at 0x9135490>
>>
>
> The fig is destroyed after it has been displayed by the console. Try
> saving it before it gets shown.
> -p
>
>
> ------------------------------------------------------------------------------
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>
>

Dear Lado,

You should be able to do it simply by calling countourf multiple times
changing the alpha value (or setting it to something like 0.5)

    plt.contourf(..., alpha=0.8, ...)
    plt.contourf(..., alpha=0.6, ...)
    plt.contourf(..., alpha=0.4, ...)

The problem comes when you want to save the figure as eps: it does not
support transparency, so the alpha level is ignored and all colors are
solid.

Cheers,

Francesco




2013/6/13 Lado Samushia <co...@gm...>

> How can I plot multiple overlaid transparent contour plots in matplotlib?
> The link below has a plot that shows I am trying to achieve.
>
> https://docs.google.com/file/d/0B4HYv5Dbtu1Zb1VtOG9PTkJCeVU/edit?usp=sharing
>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Windows:
>
> Build for Windows Store.
>
> http://p.sf.net/sfu/windows-dev2dev
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

Thank you,
I don't see a way other than starting in normal mode as the moment I type plot command it get displayed and I don't need to do a show command. 
With best regards sudheer

How can I plot multiple overlaid transparent contour plots in matplotlib?
The link below has a plot that shows I am trying to achieve.
https://docs.google.com/file/d/0B4HYv5Dbtu1Zb1VtOG9PTkJCeVU/edit?usp=sharing

On Wed, Jun 12, 2013 at 10:28 PM, Sudheer Joseph
<sud...@ya...>wrote:

> Dear experts,
> I start ipython in ipython qtconsole --pylab=inline mode and make a plot.
> But if I use savefig('fig.png') the figure do not get saved instead I get a
> blank page.
>
>  I also tried img.save('fig.png',png) but no use. Is there a way out or I
> need to do this after quitting and restarting in normal mode each time I
> want to save?
>
> ipython qtconsole --pylab=inline
>
>
> In [93]: ts.plot()
> Out[93]: <matplotlib.axes.AxesSubplot at 0x9135490>
>

The fig is destroyed after it has been displayed by the console. Try saving
it before it gets shown.
-p

Hi,

I need a twinx() plot with horizontal and vertical grid lines for the
second axis, just like the usual grid for the first axis. I don't need or
want to specify the ticks manually, though!

My example code just produces horizontal lines:

import pylab


datax = pylab.arange(50)

data1 = pylab.sin(datax)*1.5

data2 = datax**2


pylab.close('all')


fig = pylab.figure()

ax1 = fig.add_subplot(111)

ax2 = ax1.twinx()


ax1.plot(datax, data1, 'x')

ax2.plot(datax, data2, '--')


#ax1.grid()

ax2.grid()


fig.show()


Thanks in advance!

Dear experts,
I start ipython in ipython qtconsole --pylab=inline mode and make a plot. But if I use savefig('fig.png') the figure do not get saved instead I get a blank page.

 I also tried img.save('fig.png',png) but no use. Is there a way out or I need to do this after quitting and restarting in normal mode each time I want to save?

ipython qtconsole --pylab=inline
 

In [93]: ts.plot()
Out[93]: <matplotlib.axes.AxesSubplot at 0x9135490>

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