matplotlib-users Mailing List for matplotlib

Hi:

I am plotting using markers, in a similar way than this example:

http://matplotlib.sourceforge.net/examples/pylab_examples/legend_demo2.html

As you can see in the example above, the markers in the legend appear
twice: " 'green circle' 'green circle' oscillatory".

Is it possible to make the markers to appear only once, like " 'green
circle' oscillatory" ?

Regards,
Alejandro.

Thanks Sunnje,

xlim worked perfectly, I was already using ylim to increase the y
scale range to be up to 100 , never clicked to use the same for the
dates.

Cheers

On 11/30/08, Sunnje L Basedow <Sun...@nf...> wrote:
> Hi,
>  I'm also new to matplotlib and am still wrestling with my figures ....
>  Have you tried:
>  axis('tight')
>  but that will also affect the yaxis.
>  Or:
>  set_xlim(valmin, valmax)
>  Don't know if it works with date though.
>  Good luck!
>  Sünnje
>
>
>
>  -----Original Message-----
>  From: Richard Martin [mailto:bob...@go...]
>  Sent: Sun 11/30/2008 22:06
>  To: mat...@li...
>  Subject: [Matplotlib-users] plot_date - extra values added that are not
>  inmy data
>
>  Hello,
>
>  I have been wrestling with matplotlib all evening (im completely new
>  to it since a few hours ago) and finally almost have my graph
>  finished.
>
>  There is just one thing left that I can't seem to figure out myself.
>  I have attached the graph for reference (hope attachments are
>  allowed).
>
>  It is a date plot, my data starts at 16:58:11 and ends at 17:25:14 but
>  for some reason I am being given ticks for a few minutes before and a
>  few minutes after.
>
>  Is there some kind of compress, or trim function that I can use to get
>  rid of these and have the axis start at my first data point and end at
>  my last.  Or at least the nearest major tick?
>
>  Cheers
>
>

Hi, 
I'm also new to matplotlib and am still wrestling with my figures ....
Have you tried:
axis('tight')
but that will also affect the yaxis.
Or:
set_xlim(valmin, valmax)
Don't know if it works with date though.
Good luck!
Sünnje


-----Original Message-----
From: Richard Martin [mailto:bob...@go...]
Sent: Sun 11/30/2008 22:06
To: mat...@li...
Subject: [Matplotlib-users] plot_date - extra values added that are not
inmy data
 
Hello,

I have been wrestling with matplotlib all evening (im completely new
to it since a few hours ago) and finally almost have my graph
finished.

There is just one thing left that I can't seem to figure out myself.
I have attached the graph for reference (hope attachments are
allowed).

It is a date plot, my data starts at 16:58:11 and ends at 17:25:14 but
for some reason I am being given ticks for a few minutes before and a
few minutes after.

Is there some kind of compress, or trim function that I can use to get
rid of these and have the axis start at my first data point and end at
my last.  Or at least the nearest major tick?

Cheers

Hello,

I have been wrestling with matplotlib all evening (im completely new
to it since a few hours ago) and finally almost have my graph
finished.

There is just one thing left that I can't seem to figure out myself.
I have attached the graph for reference (hope attachments are
allowed).

It is a date plot, my data starts at 16:58:11 and ends at 17:25:14 but
for some reason I am being given ticks for a few minutes before and a
few minutes after.

Is there some kind of compress, or trim function that I can use to get
rid of these and have the axis start at my first data point and end at
my last.  Or at least the nearest major tick?

Cheers

Alan G Isaac wrote:
> On 11/28/2008 9:21 PM Eric Firing apparently wrote:
>> I suggest using twinx(); the scale for one line will be on the left, the 
>> scale for the other on the right.  You can make the scale colors match 
>> the line colors, if you want to.  I just updated 
>> examples/api/two_scales.py to show this.
> 
> 
> Hmmm, not here:
> http://matplotlib.sourceforge.net/examples/api/two_scales.html

The web page docs don't get updated automatically every time svn 
changes--which is probably a good thing.  The revised example is attached.

> And here the test on the y-axes does not display properly on the
> posted figures.

That's puzzling.  It looks like some odd rcParams settings must have 
been used when the figures were generated for the web page.

Eric
> 
> But I like the idea.
> 
> Alan Isaac
> 
> `
> 
> 
> 
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
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> _______________________________________________
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> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

On 11/29/2008 7:48 AM TP apparently wrote:
> In my own application, I want to specialize matplotlib.lines.Line2D to be
> able to deal with units.
> Concerning this class, is there a direct means to plot instances?


There must be.  I have not done this, but looking at
http://matplotlib.sourceforge.net/api/artist_api.html#module-matplotlib.lines
it looks like you can set the ``axes`` property and looking at the base class
http://matplotlib.sourceforge.net/api/artist_api.html#matplotlib.artist.Artist
there is a ``draw`` method.

hth,
Alan Isaac

On Thu, Nov 27, 2008 at 11:21 AM, Mauro Cavalcanti <mau...@gm...> wrote:

> Then, in a checkbox event, I do the following:
>
> index = event.GetSelection()
> plot = self.plot_list[index]
> if self.FileList.IsChecked(index):
>       plot[0].set_visible(True)
> else:
>       plot[0].set_visible(False)
>
> This works quite well and points are properly toggled on/off the Basemap.
>
> But then I want to plot minimum spanning trees connecting the point
> datasets. For this I do:
>
> n = len(nodes)
> for i in range(n):
>       try:
>               t = edges[i,0]-1
>               u = edges[i,1]-1
>               x = [nodes[t,0], nodes[u,0]]
>               y = [nodes[t,1], nodes[u,1]]
>              self.plot_list.append(map.ax.plot(x,y,'-b'))
>       except:
>               continue
>
> where nodes is the array of point coordinates and edges are the
> from/to indexes of the coordinates, computed with Prim's algorithm.
> The lines between points (representing the minimum spanning tree) are
> displayed OK. But then my problem appears: I cannot find a way to turn
> the entire tree (which is composed of n-1 line segments) on and off of
> the map in the same way I do with the points (as shown above). What I
> would like is to store all line segments inside the for loop, and then
> show the tree at once, outside the loop; so I could use the same
> "plot[0].set_visible(True|False)" I use for the points.

Hi Mauro,

Yes, you should be able to use a collection for this quite easily.
One comment first.  You never want to try/except and catch all
exceptions w/o handling them in some way.  If you want to catch a
specific exception, fine, or of you want to catch all of them and log
them and then reraise, also fine, but there is not good use case for
catching them all and then continuing silently.

Now, on to collections.  In your example above, you would simply do::

    segments = []
    n = len(nodes)
    for i in range(n):
        t = edges[i,0]-1
        u = edges[i,1]-1
        xt, yt = nodes[t,0], nodes[t,1]   # assuming xt, yt are scalars here....
        xu, yu = nodes[u,0], nodes[u,1]
        segments.append( [ (xt,yt),  (xu,yu)  ] )

    collection = collections.LineCollection(segments)

and later::

    collection.set_visible(True|False)  # etc...

Hope this helps,

JDH

On Sat, Nov 29, 2008 at 6:48 AM, TP <par...@fr...> wrote:
> Hi everybody,
>
> In my own application, I want to specialize matplotlib.lines.Line2D to be
> able to deal with units.
> Concerning this class, is there a direct means to plot instances?
>
> For example, if I do:
>
>>>> a=matplotlib.lines.Line2D([5,6],[7,8],color='m')

You can add it directly to the Axes/Subplot instance with

    ax.add_line(a)

See also the http://matplotlib.sourceforge.net/examples/pylab_examples/clippedline.html
example which shows how to create a custom, derived line class.

JDH

Hi everybody,

In my own application, I want to specialize matplotlib.lines.Line2D to be
able to deal with units.
Concerning this class, is there a direct means to plot instances?

For example, if I do:

>>> a=matplotlib.lines.Line2D([5,6],[7,8],color='m')

To plot it, I have not found another way than doing:

>>> plot(a.get_xdata(), a.get_ydata())

But it is clumsy, because if I want to keep the line color:

>>> plot(a.get_xdata(), a.get_ydata(), a.get_color())

And so on for marker style, etc.

Is there a direct means to plot a Line2D instance?

Some time ago, a colleague wrote a "Curve_2D" class from scratch, to store a
2D curve, independently from matplotlib. Instead of that, I would like to be
able to specialize Line2D matplotlib class.

Am I compelled to write a .plot() method to Line2D?

In other words, when I do:

>>> a=plot((1,2),(2,3),'r--')

I obtain a Line2D instance:

>>> a[0]
<matplotlib.lines.Line2D instance at 0x954d08c>

I would like to do the contrary: define a Line2D instance, and then plot
this Line2D. The goal is to avoid re-inventing the wheel in my application,
as did my colleague.

Thanks a lot for your help

Julien

-- 
python -c "print ''.join([chr(154 - ord(c)) for c in '*9(9&(18%.9&1+,\'Z
(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)

On 11/28/2008 9:21 PM Eric Firing apparently wrote:
> I suggest using twinx(); the scale for one line will be on the left, the 
> scale for the other on the right.  You can make the scale colors match 
> the line colors, if you want to.  I just updated 
> examples/api/two_scales.py to show this.


Hmmm, not here:
http://matplotlib.sourceforge.net/examples/api/two_scales.html
And here the test on the y-axes does not display properly on the
posted figures.

But I like the idea.

Alan Isaac

`

Eric Firing, on 2008-11-28 17:55, wrote:
> Paul Ivanov wrote:
>> Hi Jesper,
>>
>> confirming the problem over here, as well. both numpy and mpl from svn
>> (also on an Ubuntu 8.04 machine).
> 
> Just checking: did you do a clean build of numpy (deleting any old build
> directory) and then a clean build of mpl?  Distutils is not very smart
> about dependencies.
> 
> Eric

Yeah, just checked again against numpy 1.3.0.dev6118 and mpl r6456 after
clearing everything.

Paul

> 
>>
>> good luck,
>> Paul
>>
>>
>> Jesper Larsen, on 2008-11-27 02:10, wrote:
>>> Hi Eric and Mauro,
>>>
>>> Thanks for your answers.
>>>
>>> 2008/11/27 Eric Firing <ef...@ha...>:
>>>> It looks OK to me with mpl and numpy from svn.
>>> I tried upgrading to numpy from svn as well. Unfortunately the problem
>>> persists (I have attached a plot). I have seen the problem on two of
>>> my Ubuntu machines. Maybe it is caused by my specific setup and
>>> supporting libraries.
>>>
>>> Since I have a working solution and it does not seem to affect others
>>> (based on a survey of two:-) let us just leave the problem for now. If
>>> someone else encounter it please let me know and I will try to dive a
>>> bit into the issue. If the problem turns up again when I have a need
>>> to upgrade numpy (which is probably when matplotlib requires me to) I
>>> will also look into it.
>>>
>>> Best regards,
>>> Jesper
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>> -------------------------------------------------------------------------
>>>
>>> This SF.Net email is sponsored by the Moblin Your Move Developer's
>>> challenge
>>> Build the coolest Linux based applications with Moblin SDK & win
>>> great prizes
>>> Grand prize is a trip for two to an Open Source event anywhere in the
>>> world
>>> http://moblin-contest.org/redirect.php?banner_id=100&url=/
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>> _______________________________________________
>>> Matplotlib-users mailing list
>>> Mat...@li...
>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>
>>
>> -------------------------------------------------------------------------
>> This SF.Net email is sponsored by the Moblin Your Move Developer's
>> challenge
>> Build the coolest Linux based applications with Moblin SDK & win great
>> prizes
>> Grand prize is a trip for two to an Open Source event anywhere in the
>> world
>> http://moblin-contest.org/redirect.php?banner_id=100&url=/
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> 

Robin wrote:
> Hi,
> 
> I have a plot containing two lines that are quite far apart - ie one
> line oscillates around y=2, the other around y=10. The osciallations
> are small, but I would like to show the detail better (while having
> htem in a single plot).

I suggest using twinx(); the scale for one line will be on the left, the 
scale for the other on the right.  You can make the scale colors match 
the line colors, if you want to.  I just updated 
examples/api/two_scales.py to show this.

Eric

> 
> So I thought it would be nice if the y-axis scale went from 1-3 then
> had a break (denoted with some kind of cross mark), then went from
> 9-11. I tried googling but I'm not really sure what the official name
> for such a thing is, if there is one.
> 
> Is it possible to get this sort of effect with matplotlib? Or can
> people suggest an alternative (I guess I will look at doing 2 subplots
> one above the other very close together).
> 
> Cheers
> 
> Robin
> 
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

Paul Ivanov wrote:
> Hi Jesper,
> 
> confirming the problem over here, as well. both numpy and mpl from svn
> (also on an Ubuntu 8.04 machine).

Just checking: did you do a clean build of numpy (deleting any old build 
directory) and then a clean build of mpl?  Distutils is not very smart 
about dependencies.

Eric

> 
> good luck,
> Paul
> 
> 
> Jesper Larsen, on 2008-11-27 02:10, wrote:
>> Hi Eric and Mauro,
>>
>> Thanks for your answers.
>>
>> 2008/11/27 Eric Firing <ef...@ha...>:
>>> It looks OK to me with mpl and numpy from svn.
>> I tried upgrading to numpy from svn as well. Unfortunately the problem
>> persists (I have attached a plot). I have seen the problem on two of
>> my Ubuntu machines. Maybe it is caused by my specific setup and
>> supporting libraries.
>>
>> Since I have a working solution and it does not seem to affect others
>> (based on a survey of two:-) let us just leave the problem for now. If
>> someone else encounter it please let me know and I will try to dive a
>> bit into the issue. If the problem turns up again when I have a need
>> to upgrade numpy (which is probably when matplotlib requires me to) I
>> will also look into it.
>>
>> Best regards,
>> Jesper
>>
>>
>> ------------------------------------------------------------------------
>>
>>
>> ------------------------------------------------------------------------
>>
>> -------------------------------------------------------------------------
>> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
>> Build the coolest Linux based applications with Moblin SDK & win great prizes
>> Grand prize is a trip for two to an Open Source event anywhere in the world
>> http://moblin-contest.org/redirect.php?banner_id=100&url=/
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> 
> 
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

If I'm not mistaken, you might be able to write a Transform
(http://matplotlib.sourceforge.net/devel/transformations.html) to do
this, although I'm not sure how you'd render the split-mark. I don't
really know these things though, just a thought.

- Ben


On Fri, 2008-11-28 at 13:09 +0000, Robin wrote:
> Hi,
> 
> I have a plot containing two lines that are quite far apart - ie one
> line oscillates around y=2, the other around y=10. The osciallations
> are small, but I would like to show the detail better (while having
> htem in a single plot).
> 
> So I thought it would be nice if the y-axis scale went from 1-3 then
> had a break (denoted with some kind of cross mark), then went from
> 9-11. I tried googling but I'm not really sure what the official name
> for such a thing is, if there is one.
> 
> Is it possible to get this sort of effect with matplotlib? Or can
> people suggest an alternative (I guess I will look at doing 2 subplots
> one above the other very close together).
> 
> Cheers
> 
> Robin
> 
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

Hi, when I do:

   hist([0,0,0], bins=10, range=(0,10))

How come the single bin takes up the entire plot?  Same with just two 
values, or anything less than 10 - the two bars take up the entire plot, 
no matter what I plug in for range.  I'd just like 10 bins, from 0 to 9.
-- 
Yang Zhang
http://www.mit.edu/~y_z/

I tried installing mayavi on macos some months ago but I do not remember
exactly what were the problems. I know that I ended recompiling vtk from
sources and it did not work for some reason. The EPD bundle did not work
because (I think) of some conflicts between installed python version
(macpython and python from darwin ports) and the egg did not compile at
all. I tried today the last EPD on a fresh leopard install and it seems
to be working now.

Nicolas

On Fri, 2008-11-28 at 05:14 -0800, Lou Pecora wrote:
> This looks interesting.  What platform are you using?  How hard was the installation and what problems, if any, did you run into?  And their fixes?  Thanks for the info.
> 
> -- Lou Pecora,   my views are my own.
> 
> 
> --- On Thu, 11/27/08, Nicolas Rougier <nic...@lo...> wrote:
> 
> > From: Nicolas Rougier <nic...@lo...>
> > Subject: [Matplotlib-users] Simple 3D support
> > To: mat...@li...
> > Date: Thursday, November 27, 2008, 3:36 PM
> > Hi all,
> > 
> > I've been working lately on 3d visualization for my own
> > need and maybe  
> > the result may have some interest for some of you. I know
> > there is  
> > already mlab/mayavi2/vtk that does a great job, but after
> > having spent  
> > a lot of time trying to install all requirements, I headed
> > for a very  
> > fast, simple and dedicated solution. Currently, scigl (this
> > is the  
> > name of the framework) dependencies are restricted to
> > OpenGL,  GLUT,  
> > GLEW  and Boost (for python export).
> > 
> > You can find a beta version at
> > http://www.loria.fr/~rougier/scigl/index.html 
> >   and the mandatory screenshots are available at
> > http://www.loria.fr/~rougier/scigl/screenshots.html 
> > .
> > 
> > 
> > Nicolas
> > 
> > 
> > 
> >   
> > 
> > -------------------------------------------------------------------------
> > This SF.Net email is sponsored by the Moblin Your Move
> > Developer's challenge
> > Build the coolest Linux based applications with Moblin SDK
> > & win great prizes
> > Grand prize is a trip for two to an Open Source event
> > anywhere in the world
> > http://moblin-contest.org/redirect.php?banner_id=100&url=/
> > _______________________________________________
> > Matplotlib-users mailing list
> > Mat...@li...
> > https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> 
> 
>       

This looks interesting.  What platform are you using?  How hard was the installation and what problems, if any, did you run into?  And their fixes?  Thanks for the info.

-- Lou Pecora,   my views are my own.


--- On Thu, 11/27/08, Nicolas Rougier <nic...@lo...> wrote:

> From: Nicolas Rougier <nic...@lo...>
> Subject: [Matplotlib-users] Simple 3D support
> To: mat...@li...
> Date: Thursday, November 27, 2008, 3:36 PM
> Hi all,
> 
> I've been working lately on 3d visualization for my own
> need and maybe  
> the result may have some interest for some of you. I know
> there is  
> already mlab/mayavi2/vtk that does a great job, but after
> having spent  
> a lot of time trying to install all requirements, I headed
> for a very  
> fast, simple and dedicated solution. Currently, scigl (this
> is the  
> name of the framework) dependencies are restricted to
> OpenGL,  GLUT,  
> GLEW  and Boost (for python export).
> 
> You can find a beta version at
> http://www.loria.fr/~rougier/scigl/index.html 
>   and the mandatory screenshots are available at
> http://www.loria.fr/~rougier/scigl/screenshots.html 
> .
> 
> 
> Nicolas
> 
> 
> 
>   
> 
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move
> Developer's challenge
> Build the coolest Linux based applications with Moblin SDK
> & win great prizes
> Grand prize is a trip for two to an Open Source event
> anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users


      

Hi,

I have a plot containing two lines that are quite far apart - ie one
line oscillates around y=2, the other around y=10. The osciallations
are small, but I would like to show the detail better (while having
htem in a single plot).

So I thought it would be nice if the y-axis scale went from 1-3 then
had a break (denoted with some kind of cross mark), then went from
9-11. I tried googling but I'm not really sure what the official name
for such a thing is, if there is one.

Is it possible to get this sort of effect with matplotlib? Or can
people suggest an alternative (I guess I will look at doing 2 subplots
one above the other very close together).

Cheers

Robin

Hi all,

I've been working lately on 3d visualization for my own need and maybe  
the result may have some interest for some of you. I know there is  
already mlab/mayavi2/vtk that does a great job, but after having spent  
a lot of time trying to install all requirements, I headed for a very  
fast, simple and dedicated solution. Currently, scigl (this is the  
name of the framework) dependencies are restricted to OpenGL,  GLUT,  
GLEW  and Boost (for python export).

You can find a beta version at http://www.loria.fr/~rougier/scigl/index.html 
  and the mandatory screenshots are available at http://www.loria.fr/~rougier/scigl/screenshots.html 
.


Nicolas



  

Hi Jesper,

confirming the problem over here, as well. both numpy and mpl from svn
(also on an Ubuntu 8.04 machine).

good luck,
Paul


Jesper Larsen, on 2008-11-27 02:10, wrote:
> Hi Eric and Mauro,
> 
> Thanks for your answers.
> 
> 2008/11/27 Eric Firing <ef...@ha...>:
>> It looks OK to me with mpl and numpy from svn.
> 
> I tried upgrading to numpy from svn as well. Unfortunately the problem
> persists (I have attached a plot). I have seen the problem on two of
> my Ubuntu machines. Maybe it is caused by my specific setup and
> supporting libraries.
> 
> Since I have a working solution and it does not seem to affect others
> (based on a survey of two:-) let us just leave the problem for now. If
> someone else encounter it please let me know and I will try to dive a
> bit into the issue. If the problem turns up again when I have a need
> to upgrade numpy (which is probably when matplotlib requires me to) I
> will also look into it.
> 
> Best regards,
> Jesper
> 
> 
> ------------------------------------------------------------------------
> 
> 
> ------------------------------------------------------------------------
> 
> -------------------------------------------------------------------------
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Dear John,

Thank you very much for your thoughtful reply. Indeed, the code
fragment I sent was incomplete and not expected to do nothing else
than illustrate the general idea (what, hopefully, it did).

You suggested collections, and in my previous attempts I have already
used them (worked quite well, but did not solved my problem).

Perhaps my problem is a simpler than I am being able to see and it is
(still) related to using MPL/Basemap embedded in a wx GUI. Well, in my
previously presented sample application for plotting point-coordinate
datasets (in that case, corresponding to cities) on a Basemap, I have
checkboxes which I use to toggle the points on the map on and off. I
do this by storing the plot corresponding to each dataset in a Python
list, eg.

self.plot_list.append(self.map.ax.plot(longs,lats,'o'))

where map is a Basemap instance and longs,lats are float arrays of
geographic coordinates in decimal format.

Then, in a checkbox event, I do the following:

index = event.GetSelection()
plot = self.plot_list[index]
if self.FileList.IsChecked(index):
       plot[0].set_visible(True)
else:
       plot[0].set_visible(False)

This works quite well and points are properly toggled on/off the Basemap.

But then I want to plot minimum spanning trees connecting the point
datasets. For this I do:

n = len(nodes)
for i in range(n):
       try:
               t = edges[i,0]-1
               u = edges[i,1]-1
               x = [nodes[t,0], nodes[u,0]]
               y = [nodes[t,1], nodes[u,1]]
              self.plot_list.append(map.ax.plot(x,y,'-b'))
       except:
               continue

where nodes is the array of point coordinates and edges are the
from/to indexes of the coordinates, computed with Prim's algorithm.
The lines between points (representing the minimum spanning tree) are
displayed OK. But then my problem appears: I cannot find a way to turn
the entire tree (which is composed of n-1 line segments) on and off of
the map in the same way I do with the points (as shown above). What I
would like is to store all line segments inside the for loop, and then
show the tree at once, outside the loop; so I could use the same
"plot[0].set_visible(True|False)" I use for the points.

Searching the list archives, I found that more than an year ago,
another user, Mr. David Clark, had about the same problem
(http://www.nabble.com/Toggle-plot-trace-tt8968338r0.html). Your
answer to him helped me with toggling of the points, but not with the
lines.

Well, hope to have been as clear as possible.

Thanks in advance for any assistance you can provide, and for your patience!

With best regards,

2008/11/27 John Hunter <jd...@gm...>:
>
> Could you be a little bit more clear about your use case?  In the code
> above, nothing is drawn inside the loop. The Line2D is created but not
> rendered until a figure draw command is issued.  So it would help to
> know what it is that you are trying to achieve, rather than simply the
> approach to the solution you are taking.

--
Dr. Mauro J. Cavalcanti
Ecoinformatics Studio
P.O. Box 46521, CEP 20551-970
Rio de Janeiro, RJ, BRASIL
E-mail: mau...@gm...
Web: http://studio.infobio.net
Linux Registered User #473524 * Ubuntu User #22717
"Life is complex. It consists of real and imaginary parts."

Dear ALL,

Is there a way to plot a list (a Python list) of lines (MPL Line2D
objects) at once?

For example, inside a loop I have:

for i in range(n):
     line, = ax.plot(x,y)
     plot_list.append(line)

In the code fragment above, "plot_list" is an ordinary Python list
which will be filled with matplotlib.lines.Line2D objetcs, each of
them representing a line in the plot. What I would like is how (if???)
to plot this entire list of lines at once in a single plot, outside
the for loop, but obviously this cannot be done with a canonical
"plot" command.

Thanks in advance.

With regards,

-- 
Dr. Mauro J. Cavalcanti
Ecoinformatics Studio
P.O. Box 46521, CEP 20551-970
Rio de Janeiro, RJ, BRASIL
E-mail: mau...@gm...
Web: http://studio.infobio.net
Linux Registered User #473524 * Ubuntu User #22717
"Life is complex. It consists of real and imaginary parts."

Hi Eric and Mauro,

Thanks for your answers.

2008/11/27 Eric Firing <ef...@ha...>:
> It looks OK to me with mpl and numpy from svn.

I tried upgrading to numpy from svn as well. Unfortunately the problem
persists (I have attached a plot). I have seen the problem on two of
my Ubuntu machines. Maybe it is caused by my specific setup and
supporting libraries.

Since I have a working solution and it does not seem to affect others
(based on a survey of two:-) let us just leave the problem for now. If
someone else encounter it please let me know and I will try to dive a
bit into the issue. If the problem turns up again when I have a need
to upgrade numpy (which is probably when matplotlib requires me to) I
will also look into it.

Best regards,
Jesper

Jesper Larsen wrote:
> Hi matplotlib users,
> 
> The script below produces weird arrows when using numpy 1.2.1 and
> matplotlib trunk. When I reinstall numpy 1.2.0 instead it seems fine.
> I use the Agg backend. I am not sure where to start in tracking the
> bug down so I will just post the rather sparse information that I
> have.

It looks OK to me with mpl and numpy from svn.

Eric

> 
> Please let me know if you need any further information from me.
> 
> Best regards,
> Jesper
> 
> import math
> import numpy.ma as ma
> import pylab as p
> 
> a = ma.ones((10,10))
> a[:2,:] = ma.masked
> a[:,9:] = ma.masked
> b = ma.array(-a)
> nx, ny = a.shape
> 
> for i in range(nx):
>   for j in range(ny):
>     a[i,j] = a[i,j]*math.cos(i*j)
>     b[i,j] = -b[i,j]*math.sin(i*j)
> 
> print a
> 
> p.quiver(a,b)
> p.grid(True)
> p.savefig('test1.png')
> 
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I wanted to make a function to take another function that takes a 2d-vector
and returns a 2d-vector, x and y boundaries, and a resolution, and plot the
slope field.  However all I get is a blank plot over a small range and some
vertical and horizontal lines.  This is my code, if you know differential
equations with the function I'm using you should see a saddle at the origin
and a center at 1,1.

import matplotlib.pyplot as plt

def plot_system(function, xmin, xmax, ymin, ymax, resolution):
 xnow = xmin
 i = 0
 while xnow < xmax:
  ynow = ymin
  while ynow < ymax:
   direction = function([xnow, ynow])
   if direction[0]**2 + direction[1]**2 != 0:
    scale = resolution / (direction[0]**2 + direction[1]**2)**.5
    print repr(direction[0] * scale) + ", " + repr(direction[1] * scale)
    plt.arrow(xnow, ynow, direction[0] * scale, direction[1] * scale)
   ynow = ynow + resolution
  xnow = xnow + resolution
 print "plotting"
 plt.show()
 
if __name__ == "__main__":
 def function(y):
  return [y[0] - y[0]*y[1], y[0]*y[1] - y[1]]
  
 plot_system(function, -10, 10, -10, 10, 1)
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