matplotlib-users Mailing List for matplotlib

Thanks for the reply Eric,

MayaVi 2 has an imshow() function as well. Additionally, its UI allows me
visually design colormaps for my figures. It is a very useful aid, indeed.

MV also allows me view my dual-doppler analysis dia volumetrically and allow
to cut sections within 3D data. Another nice thing is that, matplotlib's
pylab and mayavi's mlab work very well inside ipython.

Gökhan

On Mon, Apr 6, 2009 at 9:34 PM, Eric Firing <ef...@ha...> wrote:

> Gökhan SEVER wrote:
>
>> Hello,
>>
>> I am trying convert a plot written in IDL to Python using matplotlib. So
>> far, I have managed to show the image on the screen equivalent to its IDL
>> output. The only problem that I could not figure out matching the colormaps
>> between them. Please see the results on this png image:
>> http://img515.imageshack.us/img515/3951/colormaps.png
>>
>> The top plot and the associated colorbar is from IDL, and the other plot
>> is using matplotlib's imshow(). I don't know how to show my lowest values in
>> the plot as white. I would be please if someone gives some insight into this
>> issue.
>>
>
> See
> http://matplotlib.sourceforge.net/examples/pylab_examples/image_masked.html
> and in particular the use of set_under().
>
> Eric
>
>>
>> Thank you all.
>>
>> Gökhan
>>
>

Hi,

I'm not a frequent user of matplotlib.dates module, so  other expert
may give you a better answer.
My understanding is that, for the date time formatting, the (x-) data
needs to be days (if not datetime instance) from some reference point
(1, 1, 1? I'm not sure).

The easiest way I can think of in your case is


 from matplotlib.dates import datetime, SEC_PER_DAY
 ordinal_today=datetime.datetime.today().toordinal()
 xvals = ordinal_today + np.arange(1200, dtype="d")/SEC_PER_DAY



Also, you'd better comment out the set_minor_locator and
set_minot_formatter calls, unless you want the same x-label drawn
twice.

IHTH,

-JJ



On Tue, Apr 7, 2009 at 3:47 PM, Brian Zambrano <br...@gm...> wrote:
> He there,
>
> I'm new to matplotlib but have really been appreciating the thorough
> documentation and examples online.  I've never worked with matlab either so
> I'm stumbling  my way around a bit, but have managed to get some basic plots
> working with my wxPython program.
>
> I'm plotting some simple time/temp curves.  For the time, I have just the
> number of seconds, starting at 0 and going up to about 1200 (20 minutes).
> I'm trying to format the xaxis so that there is a tick mark every one
> minute, and format the tick marks so they display %M:%S.  The code below
> doesn't give me *any* formatting or tick marks on the xaxis.  It seems like
> this should be fairly obvious how to accomplish, but I'm not getting it.
>
> What am I doing wrong here?
>
>
> xvals = range(1200)
> yvals = list of temps
>
> self.mainline = self.ax.plot(xvals, yvals, lw=2, color='red')[0]
>
> locator = matplotlib.dates.MinuteLocator()
> self.ax.xaxis.set_major_locator(locator)
> self.ax.xaxis.set_minor_locator(locator)
>
> formatter = matplotlib.dates.DateFormatter('%M:%S')
> self.ax.xaxis.set_major_formatter(formatter)
> self.ax.xaxis.set_minor_formatter(formatter)
>
> # draw the canvas
>
>
> Any help appreciated...thanks!
> BZ
>
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>

He there,

I'm new to matplotlib but have really been appreciating the thorough
documentation and examples online.  I've never worked with matlab either so
I'm stumbling  my way around a bit, but have managed to get some basic plots
working with my wxPython program.

I'm plotting some simple time/temp curves.  For the time, I have just the
number of seconds, starting at 0 and going up to about 1200 (20 minutes).
I'm trying to format the xaxis so that there is a tick mark every one
minute, and format the tick marks so they display %M:%S.  The code below
doesn't give me *any* formatting or tick marks on the xaxis.  It seems like
this should be fairly obvious how to accomplish, but I'm not getting it.

What am I doing wrong here?


xvals = range(1200)
yvals = list of temps

self.mainline = self.ax.plot(xvals, yvals, lw=2, color='red')[0]

locator = matplotlib.dates.MinuteLocator()
self.ax.xaxis.set_major_locator(locator)
self.ax.xaxis.set_minor_locator(locator)

formatter = matplotlib.dates.DateFormatter('%M:%S')
self.ax.xaxis.set_major_formatter(formatter)
self.ax.xaxis.set_minor_formatter(formatter)

# draw the canvas


Any help appreciated...thanks!
BZ

Thanks a lot, Jae. Your suggestion was very helpful.





Jae-Joon Lee wrote:
> 
> I guess you're using ipython in pylab mode, correct?
> If you want to make a standalone application, I recommend you not to
> use ipython pylab mode.
> Instead, use your own gui toolkit. Take a look at following examples.
> 
> http://matplotlib.sourceforge.net/examples/user_interfaces/index.html
> 
> However, a quick solution in your case would be using
> 
>   canvas = gcf().canvas
>   canvas.start_event_loop(timeout=10)
> 
> instead of time.sleep.
> 
> 
> In ipython pylab mode, the mainloop of the gui backend is blocked
> while your command is running (e.g., time.sleep function in your
> example, Tk is the only exception I know). To have your figure canvas
> responsive while you're running your code, the code you're running
> need to explicitly process the gui event of the canvas (this is what
> start_event_loop in above example is for).
> 
> Again, start_event_loop may be used in your case for a quick solution,
> but I personally recommend you to develop within the framework of your
> gui choice (matplotlib does have its own gui-neutral event model, but
> I don't think a timeout event is supported).
> 
> IHTH,
> 
> -JJ
> 
> 
> 
> On Wed, Apr 1, 2009 at 7:44 PM, VC <va...@gm...> wrote:
>> Hi all,
>>
>> I am experiencing the following difficulty:
>>
>> My program basically loops and wants to redraw a plot (using imshow() )
>> every 5 seconds or so. So it looks something like:
>>
>> ion()
>> while 1:
>>      do redraw business..
>>      time.sleep(5)
>>
>> The redrawing shows up fine, the only problem is that during the 5
>> seconds
>> of sleep, I cannot really move the figure window or really do anything
>> with
>> it.
>>
>> I am using  MPL on windows with the 'Qt4Agg' backed, and running this
>> code
>> from ipython (on the command line). I don't quite understand the
>> threading
>> model of the GUI kit, vs. the main thread, so could someone enlighten me
>> how
>> it works roughly, and what I need to do in a multi-threaded application
>> in
>> order to update a figure periodically, and be able to move it around, and
>> do
>> things with its figure window.
>>
>> Thanks in advance for any responses.
>> ------------------------------------------------------------------------------
>>
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>
>>
> 
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View this message in context: http://www.nabble.com/Being-able-to-move-figure-around-during-time.sleep%28%29-tp22838236p22931234.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

Hi,

I have an ASCII data set, which includes null data points. eg

1 x1 y1 z1
2 x2 y2 z2
3 x3 y3 z3
4      y3 z3
5      y4 z4
6      y5

I am using ipython with pylab enabled, and the load("/xxx/xxx")
function. However it chokes on the blank, "null", values. How can I
get this data set into matplotlib?

Regards,

Ciarán

Bala subramanian <bal...@gm...> writes:

> Kindly see the attached small test.dat file. I have make a plot with
> this data. But my data does nt have numerical values but has
> characters like B, T etc. So i hve give color codings for these
> characters and plot the data. Like use yellow for B, red for T etc.
> Kindly help me to do it with matplotlib.

Perhaps this will get you started:

Hello,

I am trying to create a plot and I want to disable the black frame which 
is drawn around the plot automatically. I achieved this with this setting:

mp.rcParams['axes.linewidth'] = 0

The problem is now, that I would like to have the dashed axes line, too. 
Those dashed lines do appear on the top and the left of the plot, but 
not on the lower and right border. What do I have to do to plot them 
there, too?

See attached PNG.

By the way, I am impressed by the library, I was searching quite a long 
time for something like this when I was using Matlab. Great!

Regards
Paul.

Hello,

I am trying to create a plot and I want to disable the black frame which
is drawn around the plot automatically. I achieved this with this setting:

mp.rcParams['axes.linewidth'] = 0

The problem is now, that I would like to have the dashed axes line, too.
Those dashed lines do appear on the top and the left of the plot, but
not on the lower and right border. What do I have to do to plot them
there, too?

See http://purecodes.org/stuff/sample.png

By the way, I am impressed by the library, I was searching quite a long
time for something like this when I was using Matlab. Great!

Regards
Paul.

Eric Firing <efiring@...> writes:
> 
> Solution: use
> x = arange(11)
> y = arange(11)
> 
> Eric

Thanks Eric,

That has solved my problem!

Best, Juls

Gökhan SEVER wrote:
> Hello,
> 
> I am trying convert a plot written in IDL to Python using matplotlib. So 
> far, I have managed to show the image on the screen equivalent to its 
> IDL output. The only problem that I could not figure out matching the 
> colormaps between them. Please see the results on this png image: 
> http://img515.imageshack.us/img515/3951/colormaps.png
> 
> The top plot and the associated colorbar is from IDL, and the other plot 
> is using matplotlib's imshow(). I don't know how to show my lowest 
> values in the plot as white. I would be please if someone gives some 
> insight into this issue.

See 
http://matplotlib.sourceforge.net/examples/pylab_examples/image_masked.html
and in particular the use of set_under().

Eric
> 
> Thank you all.
> 
> Gökhan

Hello,

I am trying convert a plot written in IDL to Python using matplotlib. So
far, I have managed to show the image on the screen equivalent to its IDL
output. The only problem that I could not figure out matching the colormaps
between them. Please see the results on this png image:
http://img515.imageshack.us/img515/3951/colormaps.png

The top plot and the associated colorbar is from IDL, and the other plot is
using matplotlib's imshow(). I don't know how to show my lowest values in
the plot as white. I would be please if someone gives some insight into this
issue.

Thank you all.

Gökhan

Juls Night wrote:
> I'm new to matplotlib and am really enjoying using it. I'm confused by something
> though:
[...]
> The following code produces an error though (only the length of the vectors have
> been changed):
> 
> from pylab import *
> 
> x = range(11)
> y = range(11)
> 
> m,b = polyfit(x, y, 1)
> 
> plot(x, y, 'yo', x, m*x+b, '--k')

The problem is that x is a list, not an array, and m*x yields an empty 
array:

In [17]:m*x
Out[17]:[]

In [18]:m
Out[18]:0.99999999999999978

In [19]:x
Out[19]:[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Solution: use
x = arange(11)
y = arange(11)

Eric

I'm new to matplotlib and am really enjoying using it. I'm confused by something
though:

If I plot the following linear regression it works as expected.

from pylab import *

x = range(10)
y = range(10)

m,b = polyfit(x, y, 1)

plot(x, y, 'yo', x, m*x+b, '--k')
show()

The following code produces an error though (only the length of the vectors have
been changed):

from pylab import *

x = range(11)
y = range(11)

m,b = polyfit(x, y, 1)

plot(x, y, 'yo', x, m*x+b, '--k')
show()

I'm using:
python 2.5
matplotlib 0.98.5.2
numpy 1.3.0

Below is the error message:

Traceback (most recent call last):
  File "<stdin>", line 8, in <module>
  File "/usr/lib/python2.5/site-packages/matplotlib/pyplot.py", line 2096, in plot
    ret =  gca().plot(*args, **kwargs)
  File "/usr/lib/python2.5/site-packages/matplotlib/axes.py", line 3277, in plot
    for line in self._get_lines(*args, **kwargs):
  File "/usr/lib/python2.5/site-packages/matplotlib/axes.py", line 401, in
_grab_next_args
    for seg in self._plot_3_args(remaining, **kwargs):
  File "/usr/lib/python2.5/site-packages/matplotlib/axes.py", line 340, in
_plot_3_args
    x, y, multicol = self._xy_from_xy(x, y)
  File "/usr/lib/python2.5/site-packages/matplotlib/axes.py", line 228, in
_xy_from_xy
    assert nrx == nry, 'Dimensions of x and y are incompatible'
AssertionError: Dimensions of x and y are incompatible
Unbunt Hardy 8.04

Thanks,
Juls

A quick but not necessarily accurate answer:  Don't use Python 2.6.  Use 
Python 2.5.  I don't think matplotlib has been 'certified' for 2.6 yet.

I suggest
  (1) uninstall Python 2.6 and numpy for 2.6.
  (2) Install Python 2.5 and numpy for 2.5

 (3) Install matplotlib for 2.5





Constantine <ck...@gm...> 
07/04/2009 10:19 AM

To
mat...@li...
cc

Subject
[Matplotlib-users] Installing Matplotlib






Hi,

sorry to bother you. This may be a trivial question for experienced 
Matplotlib users. I am trying to install Matplotlib under Windows XP but 
with no success. I am not familiar with Python or any of the other 
packages and I've never used Matplotlib before. I followed the 
instructions in the Matplotlib User's Manual and I have installed in the 
following sequence 1) Python(x,y)-2.1.12, 2) python-2.6.1.msi and 3) 
numpy-1.3.0-win32-superpack-python2.6.exe. Can anyone advise me on what to 
do next?

Thanks,
Constantine 
 



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Hi,

sorry to bother you. This may be a trivial question for experienced
Matplotlib users. I am trying to install Matplotlib under Windows XP but
with no success. I am not familiar with Python or any of the other packages
and I've never used Matplotlib before. I followed the instructions in the
Matplotlib User's Manual and I have installed in the following sequence 1)
Python(x,y)-2.1.12, 2) python-2.6.1.msi and 3)
numpy-1.3.0-win32-superpack-python2.6.exe. Can anyone advise me on what to
do next?

Thanks,
Constantine