matplotlib-users Mailing List for matplotlib

On 01/02/2012 08:36 AM, Chao YUE wrote:
> Dear all,
>
> I want to draw a contourf with the data covering N>45 (high latitude)
> using a 'npstere' projection.
>
> The problem is if I draw continents with a gray color,
> (m.fillcontinents(color='0.5'))
> the contourf lay which comes later will  be below the continents and
> completely invisible.
> Does anyone else have this and any suggestions?

I think you will be able to solve this problem be setting the zorder of 
each patch collection in the object returned by the call to contourf, 
something like this:

CS = contourf(Z)
for col in CS.collections:
     col.set_zorder(2.5)

The default zorder for solids is 2, so I expect that is what the filled 
continents are; boosting the patch collections to 2.5 should ensure they 
are above the continents.

Eric

>
> thanks,
>
> Chao
> --
> ***********************************************************************************
> Chao YUE
> Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL)
> UMR 1572 CEA-CNRS-UVSQ
> Batiment 712 - Pe 119
> 91191 GIF Sur YVETTE Cedex
> Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16
> ************************************************************************************
>

Done!
https://github.com/matplotlib/matplotlib/issues/654

Thanks for the support.

On Mon, Jan 2, 2012 at 16:28, Benjamin Root <ben...@ou...> wrote:
> On Mon, Jan 2, 2012 at 11:25 AM, Álvaro Justen [Turicas]
> <alv...@gm...> wrote:
>>
>> Hello,
>> When I use Figure.autofmt_xdate (it uses rotation by default) the
>> graph is not moved/scaled so it is cropped in the image.
>> I noticed this problem when I was trying to crop white border in
>> images using bbox_inches='tight' and pad_inches=0 in Figure.savefig.
>> There are attached:
>> * Simple code to reproduce the bug
>> * Output images of two cases (with and without bbox_inches + pad_inches)
>>
>> My system's info:
>> - uname -a: Linux E04679 2.6.38-13-generic #53-Ubuntu SMP Mon Nov 28
>> 19:33:45 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
>> - matplotlib version: 0.99.3, installed using pip
>> - Nothing in matplotlibrc
>> - Nothing special in verbose options
>>
>> Thanks,
>> --
>>  Álvaro Justen "Turicas"
>
>
> Turicas,
>
> Confirmed with the v1.1.x branch.  Could you file a bug report on github?
>
> Thanks!
> Ben Root
>



-- 
 Álvaro Justen "Turicas"
   http://blog.justen.eng.br http://twitter.com/turicas
   http://CursoDeArduino.com.br http://github.com/turicas
   +55 21 9898-0141

Dear all,

I want to draw a contourf with the data covering N>45 (high latitude) using
a 'npstere' projection.

The problem is if I draw continents with a gray color,
(m.fillcontinents(color='0.5'))
the contourf lay which comes later will  be below the continents and
completely invisible.
Does anyone else have this and any suggestions?

thanks,

Chao
-- 
***********************************************************************************
Chao YUE
Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL)
UMR 1572 CEA-CNRS-UVSQ
Batiment 712 - Pe 119
91191 GIF Sur YVETTE Cedex
Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16
************************************************************************************

Thanks Ben.

cheers,

Chao

2012/1/2 Benjamin Root <ben...@ou...>

> On Mon, Jan 2, 2012 at 11:10 AM, Chao YUE <cha...@gm...> wrote:
>
>> Dear all matplotlib users,
>>
>> Happy New Year.
>> I try to check the distribution of a 2D array and I find that the
>> histogram plot function doesn't respect the numpy masked array?
>>
>>
>> In [188]: a=range(1,6); b=np.array(a+a[::-1])
>>
>> In [189]: b=np.ma.masked_equal(b,2); b=np.ma.masked_equal(b,5)
>>
>> In [190]: b
>> Out[190]:
>> masked_array(data = [1 -- 3 4 -- -- 4 3 -- 1],
>>              mask = [False  True False False  True  True False False
>> True False],
>>        fill_value = 5)
>>
>>
>> In [191]: n,bins,patches=plt.hist(b)
>>
>> In [192]: n
>> Out[192]: array([2, 0, 2, 0, 0, 2, 0, 2, 0, 2])
>>
>> In [193]: n.sum()
>> Out[193]: 10
>>
>> it seems that all the elements (masked or not) are counted in the history
>> plotting?
>> and the original value is used but not the fill_value?
>>
>> I attach a figure below.
>>
>> In [194]: plt.show()
>>
>>
> Yes, this is a known issue (at least, from the comments within the
> function).  Looks like hist() uses np.asarray() instead of np.asanyarray(),
> which would result in the array being stripped of its mask.  However, I
> don't think the fix is as straight-forward as changing that to
> np.asanyarray().  I will take a peek and see what can be done.
>
> Ben Root
>
>


-- 
***********************************************************************************
Chao YUE
Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL)
UMR 1572 CEA-CNRS-UVSQ
Batiment 712 - Pe 119
91191 GIF Sur YVETTE Cedex
Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16
************************************************************************************

On Mon, Jan 2, 2012 at 11:25 AM, Álvaro Justen [Turicas] <
alv...@gm...> wrote:

> Hello,
> When I use Figure.autofmt_xdate (it uses rotation by default) the
> graph is not moved/scaled so it is cropped in the image.
> I noticed this problem when I was trying to crop white border in
> images using bbox_inches='tight' and pad_inches=0 in Figure.savefig.
> There are attached:
> * Simple code to reproduce the bug
> * Output images of two cases (with and without bbox_inches + pad_inches)
>
> My system's info:
> - uname -a: Linux E04679 2.6.38-13-generic #53-Ubuntu SMP Mon Nov 28
> 19:33:45 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
> - matplotlib version: 0.99.3, installed using pip
> - Nothing in matplotlibrc
> - Nothing special in verbose options
>
> Thanks,
> --
>  Álvaro Justen "Turicas"
>

Turicas,

Confirmed with the v1.1.x branch.  Could you file a bug report on github?

Thanks!
Ben Root

On Mon, Jan 2, 2012 at 11:10 AM, Chao YUE <cha...@gm...> wrote:

> Dear all matplotlib users,
>
> Happy New Year.
> I try to check the distribution of a 2D array and I find that the
> histogram plot function doesn't respect the numpy masked array?
>
>
> In [188]: a=range(1,6); b=np.array(a+a[::-1])
>
> In [189]: b=np.ma.masked_equal(b,2); b=np.ma.masked_equal(b,5)
>
> In [190]: b
> Out[190]:
> masked_array(data = [1 -- 3 4 -- -- 4 3 -- 1],
>              mask = [False  True False False  True  True False False  True
> False],
>        fill_value = 5)
>
>
> In [191]: n,bins,patches=plt.hist(b)
>
> In [192]: n
> Out[192]: array([2, 0, 2, 0, 0, 2, 0, 2, 0, 2])
>
> In [193]: n.sum()
> Out[193]: 10
>
> it seems that all the elements (masked or not) are counted in the history
> plotting?
> and the original value is used but not the fill_value?
>
> I attach a figure below.
>
> In [194]: plt.show()
>
>
Yes, this is a known issue (at least, from the comments within the
function).  Looks like hist() uses np.asarray() instead of np.asanyarray(),
which would result in the array being stripped of its mask.  However, I
don't think the fix is as straight-forward as changing that to
np.asanyarray().  I will take a peek and see what can be done.

Ben Root

Hello,
When I use Figure.autofmt_xdate (it uses rotation by default) the
graph is not moved/scaled so it is cropped in the image.
I noticed this problem when I was trying to crop white border in
images using bbox_inches='tight' and pad_inches=0 in Figure.savefig.
There are attached:
* Simple code to reproduce the bug
* Output images of two cases (with and without bbox_inches + pad_inches)

My system's info:
- uname -a: Linux E04679 2.6.38-13-generic #53-Ubuntu SMP Mon Nov 28
19:33:45 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
- matplotlib version: 0.99.3, installed using pip
- Nothing in matplotlibrc
- Nothing special in verbose options

Thanks,
-- 
 Álvaro Justen "Turicas"
   http://blog.justen.eng.br http://twitter.com/turicas
   http://CursoDeArduino.com.br http://github.com/turicas
   +55 21 9898-0141

On Mon, Jan 2, 2012 at 6:01 AM, Virgil Stokes <vs...@it...> wrote:

> The following link should link you to a very interesting graphical display,
>
>
> http://www.ecb.int/stats/exchange/eurofxref/html/eurofxref-graph-nok.en.html
>
> This type of graphical output (or at least something quite similar) can be
> found
> in other web pages that display financial data.
>
> Has anyone been able to produce a similar interactive graphical display
> using
> Matplotlib? A challenge for 2012 :-)
>
> --V
>

This shouldn't be too difficult. If you take a look at the event handling
examples<http://matplotlib.sourceforge.net/examples/event_handling/index.html>there
are some good starting points. For example, the data
browser example<http://matplotlib.sourceforge.net/examples/event_handling/data_browser.html>does
something similar, except you click to select data (you can change
this by hooking into 'motion_notify_event' instead of 'pick_event').

The one difficult part might be displaying your data-point info. Its easy
enough to just print out description to a terminal, but I'm not sure how
easy it is to display a tooltip. This SO
question<http://stackoverflow.com/questions/7908636/possible-to-make-labels-appear-when-hovering-over-a-point-in-matplotlib>may
help with that.

Best,
-Tony

very similar:

http://www.google.com/finance?hl=en&q=CURRENCY:AUDUSD

On 01/02/2012 05:01 AM, Virgil Stokes wrote:
> The following link should link you to a very interesting graphical display,
>
>     http://www.ecb.int/stats/exchange/eurofxref/html/eurofxref-graph-nok.en.html
>
> This type of graphical output (or at least something quite similar) can be found
> in other web pages that display financial data.
>
> Has anyone been able to produce a similar interactive graphical display using
> Matplotlib? A challenge for 2012 :-)
>
> --V
>
> ------------------------------------------------------------------------------
> Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex
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> costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox
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> Matplotlib-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

Eric Firing wrote:
>
> On Wed, Dec 28, 2011 at 1:11 AM, Jeff Whitaker <js...@fa...> wrote:
>>
>> On 12/27/11 12:07 PM, Logi Ragnarsson wrote:
>>
>>> Is it supposed to be possible to do a filled contour plot with alpha levels in the colour map? I'm plotting weather data on top of maps and would very much like to plot low levels of wind and precipitation as mostly transparent, with higher levels more opaque.
>>>
>> Logi:  It looks like alpha transparency is controlled with the alpha keyword, so you can't specify different alphas for each contour level.  You may have to call contourf multiple times, changing the alpha as needed for each set of contour levels.
>>
>> -Jeff
>
> It looks like this is something I can fix by modifying ListedColormap. It is discarding the alpha values, and I don't think there is any reason it needs to do so.
>
> Eric

I feel that this would be a worth-while improvement to the library. In
the mean-time, I have realized that the source is all there for me to
read, and I can probably create my own patched version of
ListedColormap. Actually, I've been interpolating colours to feed to
contourf, but it would be much more sensible to use a
LinearSegmentedColormap for this. Unfortunately it also discards alpha
levels.

Regards,
Logi

PS I was getting digests of the list, so I couldn't properly respond
to Eric's mail, in case the headers look funny.

The following link should link you to a very interesting graphical display,

   http://www.ecb.int/stats/exchange/eurofxref/html/eurofxref-graph-nok.en.html

This type of graphical output (or at least something quite similar) can be found 
in other web pages that display financial data.

Has anyone been able to produce a similar interactive graphical display using 
Matplotlib? A challenge for 2012 :-)

--V

On 12/30/2011 01:57 PM, Paul Ivanov wrote:
> Eric Firing, on 2011-12-27 15:31,  wrote:
>> It looks like this is something I can fix by modifying ListedColormap.
>> It is discarding the alpha values, and I don't think there is any reason
>> it needs to do so.
>
> One of my first attempts at a contribution to matplotlib three
> years ago was related to this. It was in reply to a similar
> question on list, and I wrote a patch, but never saw it through
> to inclusion because it wasn't something I needed.
>
> http://www.mail-archive.com/mat...@li.../msg09216.html
>
> I think it's a helpful starting point, as I include a discussion
> on the limitation of mpl colormaps there.

Thank you. I think that some of the sorts of changes you had in your 
patch have actually been made in the interim.  I now have a branch with 
a few small changes that I think may be all that is necessary for full 
support of variable alpha in colormaps.  I will turn it into a pull 
request shortly, after a bit more testing and inclusion of an example, 
assuming I don't run into a major problem along the way.

Eric