matplotlib-users Mailing List for matplotlib

I found that the problem occurs when I have GTKAgg WXAgg or PS backends set in
matplotlibrc file and matplotlib displays fonts properly when using GTK, WX. So
I guess that it must be something wrong with antigrain or preparing text for agg
rendering.

Any help,
regards,
Seweryn Kokot

>>>>> "Jeff" == Jeff Peery <jef...@ya...> writes:

    Jeff> hello, I'm using matplotlib and the wxAgg as a backend with
    Jeff> wxpython for a statistical process control application. I
    Jeff> would like to be able to pick points on an xy line and get
    Jeff> the index of the point. I looked at the picker_demo demo and

You could do something like the following (you'll probably want to add
some epsilon condition for closeness)


from pylab import figure, show, nx

class PickVert:
    def __init__(self, axes, line, callback):
        'call callback with the nearest vert picked'
        self.line = line
        self.axes = axes
        self.axes.figure.canvas.mpl_connect('button_press_event',
    self.pick)
        self.callback = callback

    def pick(self, event):
        if event.button!=1 or event.inaxes!=self.axes: return
        x = line.get_xdata()
        y = line.get_ydata()
        d = nx.sqrt((event.xdata - x)**2 + (event.ydata-y)**2)
        ind = nx.nonzero(d==nx.amin(d))
        self.callback(ind)

def callback(ind):
    print 'the index is', ind

fig = figure()
ax = fig.add_subplot(111)
x = nx.arange(20)
y = nx.mlab.rand(20)
line, = ax.plot(x, y, 'o')

picker = PickVert(ax, line, callback)
show()


    Jeff> I am also a bit confused as to how pylab is related to
    Jeff> matplotlib. I was informed not to use pylab if using a
    Jeff> backend and wxpython application, so I am only using
    Jeff> matplotlib. Is there a similar bind function to use for
    Jeff> binding the pick event to the callback function? thanks.

pylab is a procedural wrapper of the matplotlib API that does things
for you like manage the creation and destruction of GUI windows and it
works across multiple GUIs.  If you are writing a GUI app, you do not
want pylab to manage that for you.

JDH

Hello,

I have the following script and in matplotlib 0.87.5 (debian sid), text is not
correctly displayed, whereas in matplotlib 0.82-1 it was ok. See attached
pictures.

#!/usr/bin/python
# -*- coding: iso-8859-2 -*-
from pylab import *

ab = unicode('żłóńę','iso-8859-2')

plot([1, 3, 4],[1, 4, 2])
xlabel(ab)
show()

Any idead what is wrong
Regards,
Seweryn Kokot

I don't know how to make the "//" symbol in the y-axis, but if you  
have two plots that share the same x-axis, you can represent this  
kind of data.

The "Working with multiple figure and axes" section of the tutorial

http://matplotlib.sourceforge.net/tutorial.html

is almost right; if you turn off the display of the x-axis in the  
upper plot, it will be even better.

&C

On Oct 19, 2006, at 3:05 PM, CL wrote:

> Hi, group,
>              I am wondering if matplotlib can make a plot look like  
> the attached one. Basically, the y-axis was collapsed to show both  
> one extreme value and the rest of smaller values.
>
> Thanks.
>
> Chunlei
>
> <moz-screenshot.jpg>
>
> <moz-screenshot.jpg>
> ---------------------------------------------------------------------- 
> ---
> Using Tomcat but need to do more? Need to support web services,  
> security?
> Get stuff done quickly with pre-integrated technology to make your  
> job easier
> Download IBM WebSphere Application Server v.1.0.1 based on Apache  
> Geronimo
> http://sel.as-us.falkag.net/sel? 
> cmd=lnk&kid=120709&bid=263057&dat=121642______________________________ 
> _________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

hello, I'm using matplotlib and the wxAgg as a backend with wxpython for a statistical process control application. I would like to be able to pick points on an xy line and get the index of the point. I looked at the picker_demo demo and I have an idea of how this works but I'm a bit confused as to how to pick a vertex on a line, or if that isn't possible how to pick a marker created by scatter(). I am also a bit confused as to how pylab is related to matplotlib. I was informed not to use pylab if using a backend and wxpython application, so I am only using matplotlib. Is there a similar bind function to use for binding the pick event to the callback function? thanks.

Jeff

 		
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>>>>> "Khem" == Khem Raj <raj...@gm...> writes:

    Khem> Hi I am new to matplotlib and I am trying to use it to draw
    Khem> a matrix. I would want to give a different color to each box
    Khem> depending upon the value this matrix element has


    Khem> Could someone help me in quick start meanwhile I am looking
    Khem> into documentation.

figure()
imshow(rand(10,5), cmap=cm.jet, interpolation='nearest', aspect='auto')
colorbar()

figure()
pcolor(rand(10,5), cmap=cm.hot)


JDH

>>>>> "Johannes" == Johannes Elbs <ml....@gm...> writes:

    Johannes> Hi, I have time data stored in the format hh:mm:ss and
    Johannes> would like to plot it, having about 4 to 6 ticks labeled
    Johannes> in this format.  What I'm doing at the moment is to
    Johannes> first convert my time to seconds and plot y as function
    Johannes> of yime in seconds.

You first need to convert them to matplotlib dates.  Assume your data
are collected on Oct 10th, 2006

  import matplotlib.numerix as nx
  import datetime
  from matplotlib.dates import date2num, MINUTES_PER_DAY, SEC_PER_DAY

  d0 = date2num(datetime.date(2006,10,10))
  def convert(s):
      h,m,s = map(float, s.split(':'))
      return d0 + h/24. + m/MINUTES_PER_DAY + s/SEC_PER_DAY


In [11]: convert('12:32:02')
Out[11]: 732594.52224537032

matplotlib represents dates as days (float) since 0000-00-00

Now you need to convert your list of strings to mpl dates.  If your
list of strings is called datestrs

  dates = nx.array([convert(s) for s in datestrs])

Now when you plot you need to tell mpl you are plotting dates

  ax.plot_date(dates, vals)

We have pretty smart tick locators and tick formatters for date
plotting, so you may be happy with what you get, but if not you can
set your own

  from matplotlib.dates import DateFormatter
  ax.xaxis.set_major_formatter('%H:%M:%S')

I also find it helpful on date plots to do the following

   # move the subplot up a bit to make for rotated labels
   fig.subplots_adjust(bottom=0.15)
   for label in ax.get_xticklabels():
       label.set_rotation(30)
       label.set_horizontalalignment('right')
  

see also

  http://matplotlib.sf.net/matplotlib.dates.html
  http://matplotlib.sf.net/matplotlib.ticker.html

the users guide and the following examples

date_demo1.py
date_demo2.py
date_demo_convert.py
date_demo_rrule.py
finance_demo.py


JDH

>>>>> "Willi" == Willi Richert <w.r...@gm...> writes:

    Willi> Hi, I am plotting two graphs in one according to
    Willi> http://matplotlib.sourceforge.net/examples/two_scales.py

    Willi> I want the plot belonging to the right axis to start with
    Willi> y=0. However,

    Willi> ax2.set_ylim(ymin=0.0)

    Willi> does not affect the plot at all.

It always helps to post a complete example; otherwise we have to use
our amazing powers of deduction to figure out what you might be doing
wrong.  In this case, two possibilities come to mind:

  1) you are calling set_ylim before a plot command and the autoscaler
     is kicking on the plot command and overriding your changes.  You
     should call set_ylim after all plot commands, or turn autoscaling
     off with the autoscale_on property of the Axes

  2) you are working in interactive mode, eg ipython -pylab, and the
     draw command is not being triggered since you are making an OO
     call.  You can force a draw command in pylab with "draw" or with
     fig.canvas.draw().

The following *does* work for me, so maybe you can follow it as an
example

from pylab import *

ax1 = subplot(111)
t = arange(0.01, 10.0, 0.01)
s1 = exp(t)
plot(t, s1, 'b-')
xlabel('time (s)')
ylabel('exp')


# turn off the 2nd axes rectangle with frameon kwarg
ax2 = twinx()
s2 = sin(2*pi*t)
plot(t, s2, 'r.')
ylabel('sin')
ax2.yaxis.tick_right()
ax2.set_ylim(ymin=-3)
show()

I am sure this (superimposed Line and Bar plots) is
easy to do, but I cannot see any discussion of "how"
on the user list (difficult to know which phrase to search!)
 
Any pointers?
 
Thanks
Derek

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I have a simple, but frustrating problem.
 
I need to plot a number of series onto a boxplot.  Some sample
code looks as follows:
 
from pylab import *
from scipy import array
jan = array([46, 38, 28, 14, 11, 7,  4,  3, 3, 3, 3, 3, 3, 2, 2, 1])
#jan = array([46, 38, 28, 14, 11, 7,  4,  3, 3, 3, 3, 3]) #this length
works!!
feb = array([ 2, 12,  3,  3, 13, 10, 17, 6, 6, 6, 3, 3])
jan.shape = (-1, 1)
feb.shape = (-1, 1)
series = concatenate( (jan, feb), 1 )
figure()
boxplot(series,1)
show()
 
(In Real Life, of course, the data arrays are built up elsewhere
and passed into the plotting function...)
 
The problem is that I get the error:
ValueError: array dimensions must agree except for d_0
 
because jan and feb have different lengths - however, I have no
control
over the size of these arrays - they vary greatly according to
external
issues.
 
How do I plot multiple. variable-length array on the same boxplot?
 
Thanks
Derek

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views of the CSIR.
 
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Hi,

I have time data stored in the format hh:mm:ss and would like to plot it,
having about 4 to 6 ticks labeled in this format.
What I'm doing at the moment is to first convert my time to seconds and plot
y as function of yime in seconds.

Here the first question: Is this the way to go or is there a function I
missed which allows to directly plot from the former format?

Now I'd like to have the labels to be displayed in the hh:mm:ss format, in a
way that it automatically adopts when zooming/dezooming. Without zooming I
figured out that it is quite easy to use the xticks method, but is there a
possibility to write a function which automatically readadopts the tick
spacing?
If not, I found in the manual the dateformatter class, but if I understand
correctly, I first have to transfer the time to strftime? Or can I directly
use this class using the time starting from midnight?

Thanks for any response,
Johannes

Hi,

I am plotting two graphs in one according to 
http://matplotlib.sourceforge.net/examples/two_scales.py

I want the plot belonging to the right axis to start with y=0. However,

ax2.set_ylim(ymin=0.0)

does not affect the plot at all.

Any hints?

Regards,
wr

Khem Raj wrote:
> Hi
> 
> I have been trying to plot a matrix and want to start from top left
> corner. I tried to use 'matshow' and it worked the way I wanted but
> that could not satisfy other needs like I needed to plot something
> else over the matrix and also needed shading='faceted' which I could
> not set using matshow

matshow calls imshow.

You should be able to plot on top of an image made by matshow or imshow, 
so I don't know what the problem was with that.

> 
> So I tried to use 'pcolor' where shading is faceted by default and I
> could plot other stuff on top ofI the matrix image but I could not get
> the origin='upper' working with pcolor. I also tried with imshow but
> it did the same thing.

pcolor does not have an 'origin' kwarg but imshow does, so I don't 
understand your last sentence above.

For pcolor you need to either rearrange your matrix (e.g., 
'pcolor(flipud(Z))') or call pcolor with X and Y arguments as well as Z.

Eric