matplotlib-users Mailing List for matplotlib (Page 13)

I'm sure the radio silence to your question is just due to holidays.
Thanks for looking into this. I'd be happy to incorporate your patch 
when it is ready.
As for your question about plots that can include patches -- patches are 
virtually anything plotted that aren't lines or images. This includes 
rectangles, polygons and ellipses, for instance. See something like 
ellipse_demo.py for an example. Patches are always drawn as rectangles 
in the legend.
Cheers,
Mike
Paul Novak wrote:
> Hello,
> 
> I have further investigated problems with legend() when numpoints = 1.
> The images show what happens when numpoints = 1 for a Line2D, such as
> when calling plot(), for a LineCollection, and for a
> RegularPolyCollection, such as when using scatter(). As can be seen in
> the figures, calling legend() with numpoints = 1 results in either an
> absence of a line or a misplacement of a symbol or colored region,
> creating an ugly legend.
> 
> I have made the three figures using the script included below,
> line_collection.py from the examples, and scatter_demo.py from the 
> examples.
> 
> I will send a second message that includes a patch that attempts to fix
> the problems with legend() when numpoints=1, and some figures showing
> the improvement in the legends.
> 
> Paul
> 
> ---
> #!/usr/bin/env python
> 
> import matplotlib
> matplotlib.use('GTKAgg')
> 
> from pylab import *
> 
> x = arange(0.0, 5.0)
> y = 2.0 * x
> 
> figure(1)
> plot(x, y, 'o', label='symbol')
> plot(x, y, 'k-', label='line')
> 
> leg=legend(loc='best',numpoints=1)
> 
> show()
> 
> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
> 
> ------------------------------------------------------------------------
> 
> 
> ------------------------------------------------------------------------
> 
> 
> ------------------------------------------------------------------------
> 
> -------------------------------------------------------------------------
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-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

You can also set a custom formatter for each axis without hacking the 
matplotlib code::
 def custom_formatter(value):
 return str(value)
 gca().fmt_xdata = custom_formatter
 gca().fmt_ydata = custom_formatter
We may want to add a cleaner (more obvious) API for this -- but there 
might be good reasons that it works this way that I just don't know about.
Cheers,
Mike
Yongtao Cui wrote:
> Hi Jack,
> 
> In \matplotlib\axes.py, Axes.format_xdata()
> 
> func = self.xaxis.get_major_formatter().format_data_short
> ->func = self.xaxis.get_major_formatter().format_data
> 
> same for Axes.format_ydata()
> 
> -Yongtao
> 
> On Dec 22, 2007 1:46 PM, Jack Sankey <jac...@gm... 
> <mailto:jac...@gm...>> wrote:
> 
> Hello,
> 
> When you make a figure and move the mouse around inside the axes, the
> x- and y-values appear in the status bar. Is there a way to change the
> precision of this data? It's only tracking 3 significant figures and I
> need more (say you're zoomed in on some data with a large offset).
> 
> Is there a way to change this in matplotlibrc or some global
> preference? If not, is it a figure property?
> 
> Thanks in advance,
> Jack
> 
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> 
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-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

Hello,
On Tuesday 18 December 2007 23:42, G. O. Nikiforov wrote:
> 1. Is there a way to change the font type and font size of the numbers on
> the axes in a figure? Not the labels (xlabel and ylabel - they are easy to
> change), but the actual numbers. If for example x goes from 0 to 6 in step
> of 2, the numbers showing below the x axis would be 0, 2, 4, and 6 for
> example. It is the fontsize and font of these numbers that I want to
> change. It must be some axis property but I cannot figure it out.
I'm not sure that this is the right solution and it does not use an axes 
property, but the following works for me:
--------------------------------------------------------------------------------------------------------------
import pylab
pylab.figure()
ax = pylab.axes()
ax.plot(pylab.arange(10))
xlabels = ax.get_xticklabels()
xlabel0 = xlabels[0] # one of the xtick labels
xlabel0.get_fontsize()
xlabel0.set_fontsize(20)
pylab.show()
----------------------------------------------------------------------------------------------------------------
So finally my solution needs an iteration over a list like
--------------------------------------------------------------------------------------------------------------
for xlabel_i in ax.get_xticklabels():
 xlabel_i.set_fontsize(20)
--------------------------------------------------------------------------------------------------------------
> 3. The data that I would like to plot is in an ASCII format, where the
> first row and column is text and the rest is numbers. What would be the
> best way to import that into maplotlib and then assign a variable name to
> each column (without the first entry, which would be the variable name).
Here again I can only present an work around, but maybe it helps you 
nevertheless
-------------------------------------------------------------------------------------------------------
import numpy as n
fp = open('test.dat', "w")
fp.write('a b c \n') # write some example data
fp.write('X 1 2 \n')
fp.write('Y 3 4 \h')
fp.close()
fp = open('test.dat', "r")
rows = fp.readlines()
fp.close()
one_row = rows[0] # one line of the saved data 
print one_row
one_row_entries = one_row.split(' ')
print one_row_entries
# one would like to do something like the following to get all numbers
XY = n.zeros((2, 2), dtype=n.int32)
for i, row in enumerate(rows[1:]): # neglecting the first rows
 xy_list = row.split(' ')[1:-1] # neglecting first column and '\n'
 # convert to array and afterwards from string to integer values 
 xy_array = (n.array(xy_list)).astype(n.int32) 
 XY[i, :] = xy_array
print "XY =",XY
print "X =", XY[0, :], " and Y =", XY[1, :]
---------------------------------------------------------------------------------------------------------------
best regards,
Matthias

Hello,
I have further investigated problems with legend() when numpoints = 1.
The images show what happens when numpoints = 1 for a Line2D, such as
when calling plot(), for a LineCollection, and for a
RegularPolyCollection, such as when using scatter(). As can be seen in
the figures, calling legend() with numpoints = 1 results in either an
absence of a line or a misplacement of a symbol or colored region,
creating an ugly legend.
I have made the three figures using the script included below,
line_collection.py from the examples, and scatter_demo.py from the examples.
I will send a second message that includes a patch that attempts to fix
the problems with legend() when numpoints=1, and some figures showing
the improvement in the legends.
Paul
---
#!/usr/bin/env python
import matplotlib
matplotlib.use('GTKAgg')
from pylab import *
x = arange(0.0, 5.0)
y = 2.0 * x
figure(1)
plot(x, y, 'o', label='symbol')
plot(x, y, 'k-', label='line')
leg=legend(loc='best',numpoints=1)
show()

Hello,
I have included below a patch that attempts to fix the problems with
legend() when numpoints = 1. When numpoints = 1 and a line is plotted,
_marker == 'None', and a line segment of length handlelen is placed in
the legend; when symbols are being plotted, a single symbol is centered
in the handlelen region and placed in the legend. For LineCollection and
RegularPolyCollection, the legend when numpoints = 1 looks like the
legend when numpoints > 1; the legend always has a line or colored
region and the line or colored region and text do not overlap. The
results of the patch can be seen in the included figures.
There are some problems with the patch.
1) The variable left has to be introduced into the function
_get_handles() to properly place the legend markers.
2) Legends which contain a Patch are not handled, because I do not know
which kind of plot would result in a Patch in the legend, so I could not
test the effect of changing the legend.
3) The patch was created against 0.91.1; however, I do not think that
there is any difference in legend.py between 0.91.1 and SVN.
I would appreciate any comments or improvements on the patch.
Thanks,
Paul
diff -u a/lib/matplotlib/legend.py b/lib/matplotlib/legend.py
--- a/lib/matplotlib/legend.py	2008年01月02日 16:33:47.000000000 -0600
+++ b/lib/matplotlib/legend.py	2008年01月03日 08:56:01.000000000 -0600
@@ -273,6 +273,7 @@
 def _get_handles(self, handles, texts):
 HEIGHT = self._approx_text_height()
+ left = 0.5
 ret = [] # the returned legend lines
@@ -280,6 +281,10 @@
 x, y = label.get_position()
 x -= self.handlelen + self.handletextsep
 if isinstance(handle, Line2D):
+ if self.numpoints == 1 and handle._marker == 'None':
+ self._xdata = npy.linspace(left, left +
self.handlelen, 2)
+ elif self.numpoints == 1:
+ self._xdata = npy.array([left + self.handlelen*0.5])
 ydata = (y-HEIGHT/2)*npy.ones(self._xdata.shape, float)
 legline = Line2D(self._xdata, ydata)
 legline.update_from(handle)
@@ -298,6 +303,8 @@
 p.set_clip_box(None)
 ret.append(p)
 elif isinstance(handle, LineCollection):
+ if self.numpoints == 1:
+ self._xdata = npy.linspace(left, left +
self.handlelen, 2)
 ydata = (y-HEIGHT/2)*npy.ones(self._xdata.shape, float)
 legline = Line2D(self._xdata, ydata)
 self._set_artist_props(legline)
@@ -311,6 +318,8 @@
 ret.append(legline)
 elif isinstance(handle, RegularPolyCollection):
+ if self.numpoints == 1:
+ self._xdata = npy.array([left])
 p = Rectangle(xy=(min(self._xdata), y-3/4*HEIGHT),
 width = self.handlelen, height=HEIGHT/2,
 )

Hi,
I have some two sets of data with their x- and y-coordinates, (x1, y1) and
(x2, y2). I want to plot these curves as a parametric plot:
#########
from numpy import *
from pylab import *
t = arange (0.0 , pi/2 , 0.05)
x1= cos(t)
y1 = -sin(t)
x2 = -1+2/pi*t
y2 = -2/pi*t
# plotted as a normal plot
plot( t , x1 , t , y1 ,t , x2, t , y2)
legend(('x1','y1','x2','y2'))
show()
#########
I have read that this is done with the countour function, but I cannot
figure out how. Can somebody help me.
Also I have tried to search for information in this forum using the search
tool at the top of the page, but I could not get any hit even for obvious
queries such as "output". Is there something wrong?
Thank you in advance
Aitor

On Tue, 4 Dec 2007, John Hunter apparently wrote:
> I don't think we've purged the mscvp71 dependency -- 
> I just installed the 91.1 exe on my system and got the 
> same error on pylab import. I can fix it by dropping the 
> dll into c:\windows\system32 (and I updated the install 
> notes to this effect) but this is a pretty onerous 
> requirement for the naive user, so if we can figure out 
> how to remove the dll dependency or ship the dll, that 
> would be ideal. 
Do Python 2.4 and 2.5 ship with this DLL?
(I notice it in my Python directories, and
I did not put it there.)
Cheers,
Alan Isaac

hi Mike,
no it is WxAgg, the code is here:
-----
import wx
import os
import matplotlib
matplotlib.use('WxAgg')
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigCanvas
from matplotlib.figure import Figure
import matplotlib.numerix as numpy
class PlotFrame(wx.Frame):
 def __init__(self):
 wx.Frame.__init__(self, None, -1, "Test Printing with WX Backend")
 self.fig = Figure(None, 100)
 self.canvas= FigCanvas(self, -1, self.fig)
 self.axes = self.fig.add_axes([0.15,0.15,0.75,0.75])
 sizer = wx.BoxSizer(wx.VERTICAL)
 sizer.Add(self.canvas, 1, wx.LEFT|wx.TOP|wx.GROW)
 self.Fit()
 self.Plot_Data()
 def Print_Data(self):
 self.canvas.printerData.SetPaperId(wx.PAPER_A4)
 self.canvas.printerData.SetOrientation(wx.LANDSCAPE)
 dpi = self.canvas.figure.dpi.get()
 self.canvas.figure.dpi.set(200)
 self.canvas.Printer_Print()
 self.canvas.figure.dpi.set(dpi)
 self.canvas.draw()
 def Plot_Data(self):
 t = numpy.arange(0.0,5.0,0.01)
 s = numpy.sin(2.0*numpy.pi*t)
 c = numpy.cos(0.4*numpy.pi*t)
 self.axes.plot(t,s)
 self.axes.plot(t,c)
if __name__ == '__main__':
 app = wx.PySimpleApp()
 fig = PlotFrame()
 fig.Show(True)
 fig.Print_Data()
 app.MainLoop()
---------------------
But you got a point with usetex : I set it to False and then no more 
traceback, though the preview indicates that LANDSCAPE mode was not 
applied.
So : WxAgg seems to have issues with usetex=True, and LANDSCAPE request 
does not seem to be honored... I am using svn revision 4797.
best, and happy New Year!
Johann
Michael Droettboom wrote:
> From the traceback, it looks as if you are using the Wx backend, not the WxAgg 
> backend, and you are using "usetex" (text rendering using (La)TeX). The Wx 
> backend does not support usetex -- the WxAgg backend does. Check your 
> matplotlibrc or your matplotlib.use command and make sure you're selecting the 
> WxAgg backend.
>
> Cheers,
> Mike
> 

>From the traceback, it looks as if you are using the Wx backend, not the WxAgg 
backend, and you are using "usetex" (text rendering using (La)TeX). The Wx 
backend does not support usetex -- the WxAgg backend does. Check your 
matplotlibrc or your matplotlib.use command and make sure you're selecting the 
WxAgg backend.
Cheers,
Mike

I had similar problem before. This is a bug in 0.91.1. It has been fixed in
svn. You can try updating.
Yongtao
On Dec 31, 2007 5:21 PM, charles bartlett <csb...@co...> wrote:
> I ran the attached python program under Ubuntu and Windows2000 with
> different results. I expect the results to be similar.
>
> Running under Ubuntu works great, and as expected.
>
> Running under Windows2000 does not work well. Specifically, it works for
> awhile, but then stops working and opens a small window with title:
> wxPython: stdout/stderr, with many messages ultimately ending with the
> root issue - Cannot_Open_Resource, Could not open facefile, in
> _get_agg_font at line 301 of backend_agg.py.
>
> On Windows2000 it runs for about 1 minute, then stops working and starts
> delivering this series of error messages.
>
> On Ubuntu, I can run it all day with no problems.
>
> It might be easiest if you simply run the program under Linux and under
> Windows and see if you note the same difference.
>
> To run the program, maximize to expose the buttons and slider. Press
> Start - you should see the plot flip back-and-forth between sin and cos
> every 1 second. Move the slider to adjust the speed of flip.
>
> I know that this program could be laid out better, etc - and that is not
> my issue; this program is just a quick check of the capabilities of
> matplotlib plot updates. I am interested in supporting real-time
> plotting using matplotlib within a wxPython GUI. So, maybe you could
> suggest an alternative way to write this program that works well on
> Windows.
>
> [More fundamentally, this program should work equivalently on Windows
> and Linux. This may be a wxWidgets issue however, i.e. perhaps it
> involves how graphical resources are obtained/available/reclaimed from
> the underlying graphics subsystem of the OS. Perhaps the reclaim is much
> more efficient under Linux and I need to do some explicit resource
> reclaim under Windows (?).]
>
> BTW, if you are interested, I can clean this snippet up a little and
> maybe you would want to include it in your examples, as it demonstrates
> another aspect of matplotlib use that may be of general interest (?). Of
> course, it should first also work under Windows :).
>
> Thanks for any replies.
>
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