matplotlib-users Mailing List for matplotlib (Page 14)

Christophe Dupre a écrit :
>
> I've been developping an application using PyQT and matplotlib for a 
> while now, and instead of coding the GUI, I'd like to make use of QT 
> designer.
>
Hello,
I'm interested by your code or simple parts of it wich show intercation 
between PyQt and matplotilib.
Best regards.
Another Christophe.

Exactly. I want to plot the original data once, but the two y axes show
different scales (units). Is twinx() good for that? How?
Thanks.
Ryan May-3 wrote:
> 
> On Thu, Jun 4, 2009 at 6:01 AM, Sandro Tosi <mat...@gm...> wrote:
> 
>> Hi,
>>
>> On Thu, Jun 4, 2009 at 06:56, musik <xi....@gm...> wrote:
>> > I want to make a plot with both y axes labeled. The one on the left
>> (y1)
>> > will be in Fahrenheit, while the one on the right (y2) in Celsius. Is
>> there
>> > a way to do this?
>>
>> what you're looking for is [1]
>>
>> [1]
>> http://matplotlib.sourceforge.net/api/pyplot_api.html?highlight=twinx#matplotlib.pyplot.twinx
> 
> 
> Well you can make it work that way, but I think what the original poster
> wants is just to plot the data once, with one set of units on the left and
> another on the right. Using twinx would make two identical lines just to
> make two different scales. It seems to me that there *should* be an
> easier
> way, but I'm not sure that one exists...
> 
> Ryan
> 
> -- 
> Ryan May
> Graduate Research Assistant
> School of Meteorology
> University of Oklahoma
> Sent from Norman, Oklahoma, United States
> 
> ------------------------------------------------------------------------------
> OpenSolaris 2009.06 is a cutting edge operating system for enterprises 
> looking to deploy the next generation of Solaris that includes the latest 
> innovations from Sun and the OpenSource community. Download a copy and 
> enjoy capabilities such as Networking, Storage and Virtualization. 
> Go to: http://p.sf.net/sfu/opensolaris-get
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> 
> 
-- 
View this message in context: http://www.nabble.com/one-data-set%2C-two-y-axis-scales-tp23863680p23871873.html
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Hi John,
John Hunter <jd...@gm...> writes:
> On Thu, Jun 4, 2009 at 9:00 AM, Ole Streicher <ole...@gm...> wrote:
>> when I scroll or zoom with the mouse wheel, the scaling of the x and y
>> axes are changed within the event. I would need now the new value of
>> these to update the status bar. How can I get them without waiting for a
>> new mouse event?
>
> Not sure I understand the question... Could you be more specific,
> maybe post a code sample?
The point is that there may occure changes in the diagram axes that are
not connected to a mouse event. Example: I use the Qt backend, and
defined an QAction "zoom in" connected to the Ctrl-"+" key.
At the same time, the status bar of my application shows the position of
the mouse in the diagram. Usually, the updates of the position is
connected to the "motion_notify_event" which returns the mouse position
on change.
When the mouse is not moved, but the "zoom in" action is triggered (via
hotkey in this example), I would need to update the status bar so that
it shows the coordinated that are under the mouse cursor *after* the
zoom was applied. 
Does this make my problem better understandable?
Cheers
Ole

On Thu, Jun 4, 2009 at 9:26 AM, Ole Streicher <ole...@gm...> wrote:
>> But to answer your question about matplotlib transforms. You could do
>> ax = event.inaxes # the axes the event occurred in
>> x, y = ax.transData.transform_point((event.xdata, event.ydata))
Yes:
 xdata, ydata = ax.transData.inverted().transform_point((xdisplay, ydisplay))
And the transAxes attribute maps 0..1 relative axes position to display.
JDH

On Thu, Jun 4, 2009 at 6:01 AM, Sandro Tosi <mat...@gm...> wrote:
> Hi,
>
> On Thu, Jun 4, 2009 at 06:56, musik <xi....@gm...> wrote:
> > I want to make a plot with both y axes labeled. The one on the left (y1)
> > will be in Fahrenheit, while the one on the right (y2) in Celsius. Is
> there
> > a way to do this?
>
> what you're looking for is [1]
>
> [1]
> http://matplotlib.sourceforge.net/api/pyplot_api.html?highlight=twinx#matplotlib.pyplot.twinx
Well you can make it work that way, but I think what the original poster
wants is just to plot the data once, with one set of units on the left and
another on the right. Using twinx would make two identical lines just to
make two different scales. It seems to me that there *should* be an easier
way, but I'm not sure that one exists...
Ryan
-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma
Sent from Norman, Oklahoma, United States

Hi John,
thank you four your helpful answer.
John Hunter <jd...@gm...> writes:
> On Thu, Jun 4, 2009 at 8:49 AM, Ole Streicher <ole...@gm...> wrote:
>> def on_move(self, event)
>> mouse_pos_diag_x = ???(event.xdata)
>> mouse_pos_diag_y = ???(event.ydata)
>> where I would need to replace the ??? with some transformation from
>> event.xdata, event.ydata, and the min and max of the y axis. How could I
>> do that?
> The mouse event object already has display coords attached in the
> event.x and event.y attributes. 
My example was a bit simplified. What I want to do is to connect several
diagrams to show the same cursor. For the diagram with the mouse in it,
I can get ofcourse pixel coordinates, too. But for all other diagrams I
need to convert the cursor position to pixel coordinates.
> But to answer your question about matplotlib transforms. You could do
> ax = event.inaxes # the axes the event occurred in
> x, y = ax.transData.transform_point((event.xdata, event.ydata))
This is exactly what I need. Does the reverse transformation also exist?
Cheers
Ole

On Thu, Jun 4, 2009 at 9:00 AM, Ole Streicher <ole...@gm...> wrote:
> Hi again,
>
> when I scroll or zoom with the mouse wheel, the scaling of the x and y
> axes are changed within the event. I would need now the new value of
> these to update the status bar. How can I get them without waiting for a
> new mouse event?
Not sure I understand the question... Could you be more specific,
maybe post a code sample?
JDH

On Thu, Jun 4, 2009 at 8:49 AM, Ole Streicher <ole...@gm...> wrote:
setParent(parent)
> self.mpl_connect('motion_notify_event', self.on_move)
>
> def on_move(self, event)
> mouse_pos_diag_x = ???(event.xdata)
> mouse_pos_diag_y = ???(event.ydata)
> lower_limit_diag_y = ???
> upper_limit_diag_y = ???
> ...
>
> where I would need to replace the ??? with some transformation from
> event.xdata, event.ydata, and the min and max of the y axis. How could I
> do that?
The mouse event object already has display coords attached in the
event.x and event.y attributes. See
 http://matplotlib.sourceforge.net/api/backend_bases_api.html#matplotlib.backend_bases.LocationEvent
and
 http://matplotlib.sourceforge.net/users/event_handling.html
But to answer your question about matplotlib transforms. You could do
 ax = event.inaxes # the axes the event occurred in
 x, y = ax.transData.transform_point((event.xdata, event.ydata))
and you should get the same answer.
JDH

Hi,
I want to implement a cursor on a diagram using native Qt routines. For
this, I would need to transform data (axis) coordinates to display
coordinates.
The manual of matplotlib, API "axes" just jays that there are some
public attributes 'transData' and 'transAxis', but without an
explanation.
So, if I have something like
class DiagramWidget(FigureCanvas):
 def __init__(self, parent):
 fig = Figure()
 self.axes = fig.add_subplot(111)
 self.xlimits = (0, 4000)
 FigureCanvas.__init__(self, fig)
 self.setParent(parent)
 self.mpl_connect('motion_notify_event', self.on_move)
 def on_move(self, event)
 mouse_pos_diag_x = ???(event.xdata)
 mouse_pos_diag_y = ???(event.ydata)
 lower_limit_diag_y = ???
 upper_limit_diag_y = ???
 ...
where I would need to replace the ??? with some transformation from
event.xdata, event.ydata, and the min and max of the y axis. How could I
do that?
Cheers 
Ole

Hi again,
when I scroll or zoom with the mouse wheel, the scaling of the x and y
axes are changed within the event. I would need now the new value of
these to update the status bar. How can I get them without waiting for a
new mouse event?
Cheers
Ole

Hello there,
 
This is my first post, so first of all, thanks to the
creators/contributors of matplotlib. It's a very nice software.
 
I've been developping an application using PyQT and matplotlib for a
while now, and instead of coding the GUI, I'd like to make use of QT
designer. 
Does anyone know how I can add a MPL FigureCanvasQTAgg to a Main Window
form in QT designer? Any (simple) example would be great.
 
Thanks,
 
Christophe
 

On 6/4/2009 3:59 AM jor...@ya... apparently wrote:
> I need a file selection dialog or similar
Tkinter makes this pretty easy. E.g.,
 >>> import tkFileDialog as fd
 >>> fname = fd.askopenfilename(initialdir='c:/temp')
 >>> fname
 'C:/temp/note.jpg'
That's all, as long as you don't mind destroying
the Window manually. (Otherwise, you need just
a couple more lines.)
Cheers,
Alan Isaac

Kilian Koepsell wrote:
> Hi Jeff, I hope it is ok to contact you directly with this bug report 
> -- feel free to reply to the list if appropriate. I found your 
> previous posting through a web search, 
> <http://www.mail-archive.com/mat...@li.../msg10637.html>and 
> then tried to use your implementation in matplotlib svn.
Killian: That's fine, just please CC the mailing list.
> I noticed that the svn version is different from the one in the 
> posting above and it seems to have two bugs: * in the function 
> rgb_to_hsv_arr, the line arr = arr/255. is missing and therefore the 
> script doesn't normalize the input any more and it doesn't type-cast 
> it to float any more if used with uint8 rgb input.
That function is to be called by LightSource.shade using normalized rgb 
floats (between 0 and 1). You don't need to call it directly - instead 
just use the LightSource class as show in shading_example.py.
> This seems to cause wrong results. * the script in the current form 
> returns NaNs when applied to white [255,255,255] or white [0,0,0] 
> inputs. This can be solved by adding the following line just before 
> the return statement: out[delta==0,0] = 0 Best regards, Kilian
Again, don't use that old script you found in the email archive, but 
follow the shading_example.py example. The rgb_to_hsv function is not 
really part of the public API.
-Jeff

Hi,
On Thu, Jun 4, 2009 at 06:56, musik <xi....@gm...> wrote:
> I want to make a plot with both y axes labeled. The one on the left (y1)
> will be in Fahrenheit, while the one on the right (y2) in Celsius. Is there
> a way to do this?
what you're looking for is [1]
[1] http://matplotlib.sourceforge.net/api/pyplot_api.html?highlight=twinx#matplotlib.pyplot.twinx
Cheers,
-- 
Sandro Tosi (aka morph, morpheus, matrixhasu)
My website: http://matrixhasu.altervista.org/
Me at Debian: http://wiki.debian.org/SandroTosi

Hi,
I am working on scripts using numpy, scipy and matplotlib to analyze some image data. I would like to be able to select the particular image I want to analyze, so I need a file selection dialog or similar. I know this can be done with any gui toolkit, but I was wondering if there isn't an easier way, less involved that getting into gui programming. Would it be hard to mimic the file open button in the toolbar to do what I want?
Thanks,
jorges
 

Hi everyone,
Suppose I have the following data set
-----------------------------
Time Temperature (F)
1 78
2 79
3 79
4 77
-----------------------------
I want to make a plot with both y axes labeled. The one on the left (y1)
will be in Fahrenheit, while the one on the right (y2) in Celsius. Is there
a way to do this?
Thank you.
-- 
View this message in context: http://www.nabble.com/one-data-set%2C-two-y-axis-scales-tp23863680p23863680.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

Sebastian Haase wrote:
> Hi,
> I am still using the old "plt" package that used to be part of SciPy (
> I fixed it up, kept it alive and it runs now fine with numpy).
> I would really like to switch to matplotlib (using the wx backend) but
> I'm having concerns regarding speed.
> 
> So I was wondering what are other people's speed benchmarks are like
> -- to do something like a simple
>>>> a = numpy.arange(500)
>>>> mpl.plot(a)
> 
> I timed it and it took something like 50ms for a repeat of the plot command.
> With my plt plotting package it is probably 10-50x faster.
> 
> I want to interactively plot and update (using the clear and plot
> commands) things like image "line profiles" i.e. 512 points graphs.
> Another example is that I started playing with ODEs (like
> http://www.scipy.org/LoktaVolterraTutorial) and tried to make a small
> gui to (like a Trait slider) for some parameters and the plotting
> would make it completely unresponsive (plt worked again very fast --
> super ugly, but fast ;-) )
> 
> Is there a special way to update plots very fast, i.e. faster than
> clr();plot(...) ?
I would not say "very fast", but check out the animation examples here:
http://matplotlib.sourceforge.net/examples/index.html.
Eric

Hi,
I noticed that vertical and horizontal lines with a line width < 1 are 
displayed with a line width of 1 on WxAgg with recent version of matplotlib.
I use matplotlib 0.98.5.2 on Windows XP, and Ubuntu Linux 9.04.
For example :
 >>> import pylab
 >>> pylab.plot([0,0],[0,1],linewidth=*0.5*)
[<matplotlib.lines.Line2D object at 0x031FE510>]
 >>> pylab.show()
and
 >>> import pylab
 >>> pylab.plot([0,0],[0,1],linewidth=*1*)
[<matplotlib.lines.Line2D object at 0x031FE510>]
 >>> pylab.show()
produce the same result.
The same bug occurs when I export the figure as a png (but not on pdf 
export). It did not occur on earlier matplotlib releases (at least, not 
on 0.91.2).
Sorry if this is a known bug, or even an already corrected one, but I 
couldn't find any mention of it on Sourceforge last changelog, nor 
elsewhere.
Nicolas

Hi,
I am still using the old "plt" package that used to be part of SciPy (
I fixed it up, kept it alive and it runs now fine with numpy).
I would really like to switch to matplotlib (using the wx backend) but
I'm having concerns regarding speed.
So I was wondering what are other people's speed benchmarks are like
-- to do something like a simple
>>> a = numpy.arange(500)
>>> mpl.plot(a)
I timed it and it took something like 50ms for a repeat of the plot command.
With my plt plotting package it is probably 10-50x faster.
I want to interactively plot and update (using the clear and plot
commands) things like image "line profiles" i.e. 512 points graphs.
Another example is that I started playing with ODEs (like
http://www.scipy.org/LoktaVolterraTutorial) and tried to make a small
gui to (like a Trait slider) for some parameters and the plotting
would make it completely unresponsive (plt worked again very fast --
super ugly, but fast ;-) )
Is there a special way to update plots very fast, i.e. faster than
clr();plot(...) ?
Regards,
Sebastian Haase

On Wed, Jun 3, 2009 at 12:33 PM, TP <par...@fr...> wrote:
> Hi everybody,
>
> I want to delete a subplot from my figure. How to do that?
>
> For example, I would like to remove the right subplot in the following
> example:
>
> ########################
> from pylab import *
>
> ion()
> f = figure()
> s = f.add_subplot("121")
> X1 = arange( 0.0, 5.0, 0.1 )
> s.plot( X1, X1**2)
>
> s = f.add_subplot("122")
> s.plot( X1, sqrt( X1 ))
Hmm, I didn't know you could pass a string in for the subplot arg :-)
Call f.delaxes(s) where s is the subplot instance you want to remove
JDH

Thanks John. The bar_stacked example does not seem to work for histograms, but I'm glad to know that we could manually make the legends. 
I still do not know how to specify the colors of the "stacks" in my histogram, so adding the manual legends for them is still a pain -- but at least doable since I can figure it out from the actual data.
best,
amit shrestha
John Hunter wrote:
> On Tue, Jun 2, 2009 at 3:15 PM, Amit <ror...@gm...> wrote:
> 
>> Hi all,
>>
>> Has any of you had any luck with creating stacked histograms using
>> matplotlib? It seems to work but I have no idea how to label (or add the
>> legend) or choose the colors of the stacks. Below is a sample code for
>> creating a stacked histogram. Can anyone help please? Unlike the "bar()"
>> function, hist() doesn't seem to have the color/colors parameter.
>>
>> #!/usr/bin/python
>>
>> import sys
>> import matplotlib.pyplot as pyplot
>> import numpy as numpy
>>
>> page_numbers_one = (100,100,500,600,800)
>> page_numbers_two = (100,100,500,600,800,100,100,100,100,100)
>> page_numbers_three = (900,100,500,600,800,500)
>>
>> pyplot.hist((page_numbers_one,page_numbers_two,page_numbers_three),histtype='barstacked',bins=5)
>>
>> pyplot.show()
>>
>> 
>
> Have you seen this example:
>
> http://matplotlib.sourceforge.net/examples/pylab_examples/bar_stacked.html
>
> To create the legend, it is best to create proxy objects, eg
> Rectangles, with the right colors and manually add them to the legend.
> See
>
> http://matplotlib.sourceforge.net/users/plotting/legend.html#using-proxy-artist
>
> JDH
> 

Hi everybody,
I want to delete a subplot from my figure. How to do that?
For example, I would like to remove the right subplot in the following
example:
########################
from pylab import *
ion()
f = figure()
s = f.add_subplot("121")
X1 = arange( 0.0, 5.0, 0.1 )
s.plot( X1, X1**2)
s = f.add_subplot("122")
s.plot( X1, sqrt( X1 ))
show()
########################
Thanks in advance,
Julien
-- 
python -c "print ''.join([chr(154 - ord(c)) for c in '*9(9&(18%.\
9&1+,\'Z4(55l4('])"
"When a distinguished but elderly scientist states that something is
possible, he is almost certainly right. When he states that something is
impossible, he is very probably wrong." (first law of AC Clarke)

Can you provide a standalone script that causes the segfault so we can 
try to reproduce? Backtraces from gdb and valgrind "memcheck" logs 
would also be helpful.
Mike
Kazansky, Stella (SKAZANSK) wrote:
>
> Hello,
> I am not sure that matplotlib is the cause, we are looking for it, but 
> we are having multiple segfaults using python 2.6 on 64 bits linux boxes.
>
> Everything was recompiled for 64 bits.
> Did anybody encounter similar problem?
>
> Thanks
>
> ------------------------------------------------------------------------
>
> ------------------------------------------------------------------------------
> OpenSolaris 2009.06 is a cutting edge operating system for enterprises 
> looking to deploy the next generation of Solaris that includes the latest 
> innovations from Sun and the OpenSource community. Download a copy and 
> enjoy capabilities such as Networking, Storage and Virtualization. 
> Go to: http://p.sf.net/sfu/opensolaris-get
> ------------------------------------------------------------------------
>
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> 
-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

 Hello,
I am not sure that matplotlib is the cause, we are looking for it, but we
are having multiple segfaults using python 2.6 on 64 bits linux boxes.
Everything was recompiled for 64 bits.
Did anybody encounter similar problem?
Thanks

On Tue, Jun 2, 2009 at 10:09 AM, Anu Pakanati <apa...@ho...> wrote:
> Lastly, my gcc version is gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4)
>
> I did have matplotlib and player/stage playing nicely in a previous
> incarnation, using older versions of both from about 8 months ago.
> Unfortunately going back is not an option for me, and since this seems like
> it may be a third party conflict, I may need to refactor my code to avoid
> loading both in the same script. But any help would be appreciated!
>
> Thanks for your attention!
We've seen this before -- where importing matplotlib/pylab and some
other application trigger some strange interference. Unfortunately,
we've never figured it out. I've always suspected that there may be
two libraries compiled against different versions of numpy/numeric
that may be causing trouble, but this is just a hunch. Did you
compile numpy, mpl and player/stage from src, or was one or more of
them provided by an installer. I suggest trying clean src builds of
all, and then posting back. Also, do some ldd's on the python
extension code modules, and post some of the results here. Perhaps
something will jump out at me (not holding breath).
JDH