matplotlib-users Mailing List for matplotlib

On 7/15/11 12:55 PM, Benjamin Root wrote:
> On Fri, Jul 15, 2011 at 1:44 PM, Yoshi Rokuko <yo...@ro... 
> <mailto:yo...@ro...>> wrote:
>
>     +--------------------------------------------- Jeff Whitaker
>     -----------+
>     > On 7/14/11 2:25 PM, Yoshi Rokuko wrote:
>     > > hi, is it possible to restrict a contour plot to a
>     > > country? if i grid my data to projection coordinates
>     > > and then make a contour plot i can draw the country
>     > > borders on top, but since the data plotted outside
>     > > the country is a gridding artifact i would rather
>     > > not plot it.
>     >
>     > Yoshi:  There is no mechanism for doing this.  It is possible,
>     but you
>     > would need a way to create a mask for all the grid points
>     outside the
>     > country of interest, and then use this mask to create a masked
>     array to
>     > pass to contourf.
>     >
>     > -Jeff
>
>     wouldn't it be possible to create such a mask using internals from
>     Basemap.drawcountries() somehow?
>
>     best regards, yoshi
>
>
> Jeff, I just had a thought....
>
> Isn't the country borders drawn as Path or Polygon objects?  I believe 
> there are some matplotlib internal functions that can be given a list 
> of points (such as those for a grid) and a path and it will return 
> which points are within the path and which are outside.  One could use 
> that to make the mask.
>
> Might make for a nice feature for basemap in the upcoming v1.1.0 release.
>
> Ben Root
>
Ben/Yoshi:  The countries are not polygons, they are line segments. 
Worse yet, they are all just lumped together with no metadata (no way to 
know which lines define the country you want). If you had a shapefile 
with just the country of interest in it, defined as a polygon, then it's 
doable  You could take a look at the source code for the is_land method, 
which tests to see if a given x,y point is inside any of the continent 
polygons.

Let us know if you have you have the country polygon, and then I can 
help you with the details.

-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

On Fri, Jul 15, 2011 at 1:44 PM, Yoshi Rokuko <yo...@ro...> wrote:

> +--------------------------------------------- Jeff Whitaker -----------+
> > On 7/14/11 2:25 PM, Yoshi Rokuko wrote:
> > > hi, is it possible to restrict a contour plot to a
> > > country? if i grid my data to projection coordinates
> > > and then make a contour plot i can draw the country
> > > borders on top, but since the data plotted outside
> > > the country is a gridding artifact i would rather
> > > not plot it.
> >
> > Yoshi:  There is no mechanism for doing this.  It is possible, but you
> > would need a way to create a mask for all the grid points outside the
> > country of interest, and then use this mask to create a masked array to
> > pass to contourf.
> >
> > -Jeff
>
> wouldn't it be possible to create such a mask using internals from
> Basemap.drawcountries() somehow?
>
> best regards, yoshi
>
>
Jeff, I just had a thought....

Isn't the country borders drawn as Path or Polygon objects?  I believe there
are some matplotlib internal functions that can be given a list of points
(such as those for a grid) and a path and it will return which points are
within the path and which are outside.  One could use that to make the mask.

Might make for a nice feature for basemap in the upcoming v1.1.0 release.

Ben Root

+--------------------------------------------- Jeff Whitaker -----------+
> On 7/14/11 2:25 PM, Yoshi Rokuko wrote:
> > hi, is it possible to restrict a contour plot to a
> > country? if i grid my data to projection coordinates
> > and then make a contour plot i can draw the country
> > borders on top, but since the data plotted outside
> > the country is a gridding artifact i would rather
> > not plot it.
> 
> Yoshi:  There is no mechanism for doing this.  It is possible, but you 
> would need a way to create a mask for all the grid points outside the 
> country of interest, and then use this mask to create a masked array to 
> pass to contourf.
> 
> -Jeff

wouldn't it be possible to create such a mask using internals from
Basemap.drawcountries() somehow?

best regards, yoshi

On 7/14/11 2:25 PM, Yoshi Rokuko wrote:
> hi, is it possible to restrict a contour plot to a
> country? if i grid my data to projection coordinates
> and then make a contour plot i can draw the country
> borders on top, but since the data plotted outside
> the country is a gridding artifact i would rather
> not plot it.

Yoshi:  There is no mechanism for doing this.  It is possible, but you 
would need a way to create a mask for all the grid points outside the 
country of interest, and then use this mask to create a masked array to 
pass to contourf.

-Jeff
>
> to make it more clear what i mean:
> http://rokuko.net/basicmap.png
>
> any ideas? can one make a single country transparent?
>
> best regards, yoshi
>
> ------------------------------------------------------------------------------
> AppSumo Presents a FREE Video for the SourceForge Community by Eric
> Ries, the creator of the Lean Startup Methodology on "Lean Startup
> Secrets Revealed." This video shows you how to validate your ideas,
> optimize your ideas and identify your business strategy.
> http://p.sf.net/sfu/appsumosfdev2dev
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

On Fri, Jul 15, 2011 at 11:42 AM, robert rottermann <ro...@re...>wrote:

> **
> On 15.07.2011 17:56, Benjamin Root wrote:
>
>
>
> On Fri, Jul 15, 2011 at 10:49 AM, robert <ro...@re...> wrote:
>
>> Hi there,
>> I am all new to mathlib world..
>>
>> What I try to do is plotting some charts over an image.
>> I would be very grateful, if somebody could provide me with an example.
>> thanks
>> robert
>>
>>
> Welcome Robert,
>
> This is fairly straight-forward.  If you have a image file, you can plot it
> like so:
>
> >>> import matplotlib.pyplot as plt
> >>> imData = plt.imread("foobar.png")
> >>> plt.imshow(imData)
>
> Now, the tricky issue is that the coordinate system for the plot may be a
> bit backwards than you might want for normal plotting.  The (0, 0)
> coordinate will be in the upper-left instead of the lower-left.  Plus, the
> axis limits will be in pixels.  This may or may not be an issue depending on
> what you plan to plot on top of the image.  And, of course, unless you are
> in interactive mode, you will need to do a "plt.show()" call when you are
> finished building the plot and want to display it to the screen.
>
> I hope this helps and let us know if you have any other questions!
> Ben Root
>
>   thank a lot Ben,
> it feels really good when you get answers that fast ..
> one more question: can I as imData what dimensions it has?
>
> thanks
> robert
>
>
That is quite straight-forward:

>>> print imData.shape

matplotlib uses NumPy for its numerical data arrays.  You might want to read
up on its documentation here:

http://docs.scipy.org/doc/numpy/user/
http://docs.scipy.org/doc/numpy/reference/

I hope this helps!
Ben Root

On 07/14/2011 08:08 PM, ruggit wrote:
> Hi,
>
> How to set the ticks width through rc?
> Something like: rc('xtick.major', size=6), but for the width? I cannot
> find the proper key.

There isn't one, and probably should be.  You might want to file an 
issue on github.

As a workaround, if you are not using any other markers in the plot, you 
can use the lines.markeredgewidth key; ticks are actually markers.

With mpl >= 1.0 you can also use the tick_params function or Axes method 
once you have created your Axes instance, e.g.:

plot([1,2,3])
tick_params(width=2, length=4)

Eric

>
> Thanks.
> R.
>
> ------------------------------------------------------------------------------
> AppSumo Presents a FREE Video for the SourceForge Community by Eric
> Ries, the creator of the Lean Startup Methodology on "Lean Startup
> Secrets Revealed." This video shows you how to validate your ideas,
> optimize your ideas and identify your business strategy.
> http://p.sf.net/sfu/appsumosfdev2dev
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

On 15.07.2011 17:56, Benjamin Root wrote:
>
>
> On Fri, Jul 15, 2011 at 10:49 AM, robert <ro...@re... 
> <mailto:ro...@re...>> wrote:
>
>     Hi there,
>     I am all new to mathlib world..
>
>     What I try to do is plotting some charts over an image.
>     I would be very grateful, if somebody could provide me with an example.
>     thanks
>     robert
>
>
> Welcome Robert,
>
> This is fairly straight-forward.  If you have a image file, you can plot it 
> like so:
>
> >>> import matplotlib.pyplot as plt
> >>> imData = plt.imread("foobar.png")
> >>> plt.imshow(imData)
>
> Now, the tricky issue is that the coordinate system for the plot may be a bit 
> backwards than you might want for normal plotting.  The (0, 0) coordinate will 
> be in the upper-left instead of the lower-left.  Plus, the axis limits will be 
> in pixels.  This may or may not be an issue depending on what you plan to plot 
> on top of the image.  And, of course, unless you are in interactive mode, you 
> will need to do a "plt.show()" call when you are finished building the plot 
> and want to display it to the screen.
>
> I hope this helps and let us know if you have any other questions!
> Ben Root
>
thank a lot Ben,
it feels really good when you get answers that fast ..
one more question: can I as imData what dimensions it has?

thanks
robert

On Fri, Jul 15, 2011 at 10:49 AM, robert <ro...@re...> wrote:

> Hi there,
> I am all new to mathlib world..
>
> What I try to do is plotting some charts over an image.
> I would be very grateful, if somebody could provide me with an example.
> thanks
> robert
>
>
Welcome Robert,

This is fairly straight-forward.  If you have a image file, you can plot it
like so:

>>> import matplotlib.pyplot as plt
>>> imData = plt.imread("foobar.png")
>>> plt.imshow(imData)

Now, the tricky issue is that the coordinate system for the plot may be a
bit backwards than you might want for normal plotting.  The (0, 0)
coordinate will be in the upper-left instead of the lower-left.  Plus, the
axis limits will be in pixels.  This may or may not be an issue depending on
what you plan to plot on top of the image.  And, of course, unless you are
in interactive mode, you will need to do a "plt.show()" call when you are
finished building the plot and want to display it to the screen.

I hope this helps and let us know if you have any other questions!
Ben Root

Hi there,
I am all new to mathlib world..

What I try to do is plotting some charts over an image.
I would be very grateful, if somebody could provide me with an example.
thanks
robert

Gerald, Eric, the code was very useful and run without any problem. many thanks 
for your help. -- Armagan 
----------------------------------------------------
Armagan Tarim
http://yunus.hacettepe.edu.tr/~armo/
----------------------------------------------------




________________________________
From: Gerald Storer <gd...@mr...>
To: mat...@li...
Cc: ar...@ya...
Sent: Fri, July 15, 2011 5:47:34 AM
Subject: Re: [Matplotlib-users] matplotlib + pyside

As Eric said Github master works with PySide.  If you can't wait for a 
release and you don't want to run the Github version of MPL you can use 
the following code to render a plot inside a PySide app.  Note that this 
will just show the plot image.  You won't get the tool bar, status bar 
or any other GUI elements.

Gerald.

Hi,

How to set the ticks width through rc?
Something like: rc('xtick.major', size=6), but for the width? I cannot
find the proper key.

Thanks.
R.

As Eric said Github master works with PySide.  If you can't wait for a 
release and you don't want to run the Github version of MPL you can use 
the following code to render a plot inside a PySide app.  Note that this 
will just show the plot image.  You won't get the tool bar, status bar 
or any other GUI elements.

Gerald.

On 14/07/2011 3:33 PM, Eric Firing wrote:
> On 07/13/2011 09:18 PM, Armagan Tarim wrote:
>> Hi All,
>> I have tried the sample PySide code given at
>> http://www.scipy.org/Cookbook/Matplotlib/PySide
>> the below excerpt is from my "Python Shell" for this sample code, which
>> gives this error,
> Github master works with pyside.  It is expected to emerge as a release
> within a few weeks.
>
> Eric
>
>> "ImportError: Warning: formlayout requires PyQt4>v4.3"
>> It seems that it is looking for PyQt; but the whole point of using
>> PySide is to avoid using PyQt.
>> Any help is appreciated.
>> -- Armagan
>> Python 2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit
>> (Intel)] on win32
>> Type "copyright", "credits" or "license()" for more information.
>>   >>>  import sys
>>   >>>  import matplotlib
>>   >>>  matplotlib.use('Qt4Agg')
>>   >>>  import pylab
>> Traceback (most recent call last):
>> File "<pyshell#3>", line 1, in<module>
>> import pylab
>> File "C:\Python27\lib\site-packages\pylab.py", line 1, in<module>
>> from matplotlib.pylab import *
>> File "C:\Python27\lib\site-packages\matplotlib\pylab.py", line 263, in
>> <module>
>> from matplotlib.pyplot import *
>> File "C:\Python27\lib\site-packages\matplotlib\pyplot.py", line 95, in
>> <module>
>> new_figure_manager, draw_if_interactive, show = pylab_setup()
>> File "C:\Python27\lib\site-packages\matplotlib\backends\__init__.py",
>> line 25, in pylab_setup
>> globals(),locals(),[backend_name])
>> File
>> "C:\Python27\lib\site-packages\matplotlib\backends\backend_qt4agg.py",
>> line 12, in<module>
>> from backend_qt4 import QtCore, QtGui, FigureManagerQT, FigureCanvasQT,\
>> File "C:\Python27\lib\site-packages\matplotlib\backends\backend_qt4.py",
>> line 18, in<module>
>> import matplotlib.backends.qt4_editor.figureoptions as figureoptions
>> File
>> "C:\Python27\lib\site-packages\matplotlib\backends\qt4_editor\figureoptions.py",
>> line 11, in<module>
>> import matplotlib.backends.qt4_editor.formlayout as formlayout
>> File
>> "C:\Python27\lib\site-packages\matplotlib\backends\qt4_editor\formlayout.py",
>> line 51, in<module>
>> raise ImportError, "Warning: formlayout requires PyQt4>v4.3"
>> ImportError: Warning: formlayout requires PyQt4>v4.3
>>
>> -------------------------------------------------
>>

The following helpers do the trick for me:

def set_foregroundcolor(ax, color):
     '''For the specified axes, sets the color of the frame, major ticks,
         tick labels, axis labels, title and legend
     '''
     for tl in ax.get_xticklines() + ax.get_yticklines():
         tl.set_color(color)
     for spine in ax.spines:
         ax.spines[spine].set_edgecolor(color)
     for tick in ax.xaxis.get_major_ticks():
         tick.label1.set_color(color)
     for tick in ax.yaxis.get_major_ticks():
         tick.label1.set_color(color)
     ax.axes.xaxis.label.set_color(color)
     ax.axes.yaxis.label.set_color(color)
     ax.axes.title.set_color(color)
     lh = ax.get_legend()
     if lh != None:
         lh.get_title().set_color(color)
         lh.legendPatch.set_edgecolor(color)
         labels = lh.get_texts()
         for lab in labels:
             lab.set_color(color)

def set_backgroundcolor(ax, color):
     '''Sets the background color of the current axes (and legend).
         Use 'None' (with quotes) for transparent. To get transparent
         background on saved figures, use:
         pp.savefig("fig1.svg", transparent=True)
     '''
     ax.patch.set_facecolor(color)
     lh = ax.get_legend()
     if lh != None:
         lh.legendPatch.set_facecolor(color)

-- 
Christopher Brown, Ph.D.
Associate Research Professor
Department of Speech and Hearing Science
Arizona State University
http://pal.asu.edu