matplotlib-users Mailing List for matplotlib (Page 2)

How can I keep a 1:1 aspect ratio after adding a colorbar?

ratio='exact' seems to include the colorbar in the calculations.  For
example, if I have a circle and color it....I want it to still look like a
circle (rather than an ellipse) after adding the colorbar.

~t

Any comments on this?  The behavior is, at best, inconsistent.  At worst,
the current behavior is incorrect, as it is not possible to have a white
facecolor when using usetex/xpdf.

On 9/23/07, Tom Johnson <tj...@gm...> wrote:
>
> On 9/23/07, Tom Johnson <tj...@gm...> wrote:
> >
> >
> > Also, it seems like there needs to be an extra keyword or option.
> > Suppose someone wanted a white facecolor in the (usetex=True) EPS file.  It
> > doesn't seem like this is currently possible.  It would be nice if I could
> > specify:
> >
> > savefig(file, facecolor=None, edgecolor=None)
>
>
> It would also be nice if we could specify the axis background color to be
> None as well (again, perhaps only useful when creating an EPS)...when using
> the plot command.
>
>
>

David Huard wrote:
> Hi Dirk,
> 
> If you haven't already done so, look at the numpy.ma <http://numpy.ma/> 
> module. It provides a masked array object that deals gracefully with 
> missing values. To the best of my knowledge, most matplotlib functions 
> understand masked arrays and deal with it accordingly, exception made of 
> those requiring a full matrix (such as contour). Take a look at 

contour handles masked arrays correctly, as far as I know; contourf has 
some bugs in its masked array handling, but depending on the type and 
distribution of voids, it may still be good enough.

pcolor and image have no problems with masked arrays.

Eric

> examples/image_masked.py. Also, in the Basemap toolkit, there is at 
> least one example showing how to plot a masked array on a map.
> 
> Cheers,
> 
> David

Hi Dirk,

If you haven't already done so, look at the numpy.ma module. It provides a
masked array object that deals gracefully with missing values. To the best
of my knowledge, most matplotlib functions understand masked arrays and deal
with it accordingly, exception made of those requiring a full matrix (such
as contour). Take a look at examples/image_masked.py. Also, in the Basemap
toolkit, there is at least one example showing how to plot a masked array on
a map.

Cheers,

David

2007/9/26, Dirk Zickermann <dir...@go...>:
>
> Dear matplotlib group,
>
> for the represenation of 2d measurement data I use the contourplot
> function from matplotlib. Some points in this map are not measurabel,
> therefore I get a non numerical value (nan) output.
>
> From this data I want to generate a map and a histogram plot. This works
> fine, as long as I use regular matrix/array data structure without any
> voids.
>
> My questions are:
> (1) How can I make use of plotting data with NAN values as contour and
> asigns such values eg as black points?
> (2) How can I use the matplotlib hist() function with this data, that also
> include such missing data points?
> Maybe there is an easy workaround for this.
>
> Thanks a  lot for your support,
> Dirk
>
> (python2.51 /matplotlib-0.90.1, win32)
>
> my code:
> ...
> import matplotlib
> ...
> my2dData=[[1,2,3,4,5.0 ,NaN,7,8,9,10],[10,9,8,7,6,5,4,3,2,1]]
> ...
> figure(1)
> imshow(my2dData)
> pylab.show()
> ..
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>

Hi,

=20

I 'm writing a python program that draws figures one by one
interactively with the user's input in dos mode. Basically, I give the
program a decision after each figure and then it draws the next one.
After the first figure, it got very much slowed down for the second one
and crashed for the third one. I feel like it has some memory issues as
I keep using 'show' after I close each. I used 'clf()' before I draw a
new one, but it doesn't seem to help. Any idea? Thanks.

=20

Young Jin

Dirk Zickermann wrote:
> Dear matplotlib group,
> 
> for the represenation of 2d measurement data I use the contourplot
> function from matplotlib. Some points in this map are not measurabel,
> therefore I get a non numerical value (nan) output.
> 
> From this data I want to generate a map and a histogram plot. This works
> fine, as long as I use regular matrix/array data structure without any
> voids.
> 
> My questions are:
> (1) How can I make use of plotting data with NAN values as contour and
> asigns such values eg as black points?

I'm not sure what you mean.  For a contour plot, you're not assigning
any kind of color to data, but drawing boundaries that enclose regions
with a value greater/less than a certain value.  Since, AFAIK,
contouring requires regularly spaced data, you might want to try
interpolating to fill in the missing data before contouring.

If instead, you actually want an image plot (data->colored points), I
thought pcolor at least supported ignoring NaN points.

> (2) How can I use the matplotlib hist() function with this data, that
> also include such missing data points?
> Maybe there is an easy workaround for this.

My solution here would be to create a new 1D array with the NaN points
deleted before calling hist()

Ryan

-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma

Hello,

I just installed Matplotlib (and NumPy) on a windows XP machine, and
I'm getting the following traceback when I try to use the TkAgg
backend.

Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit (Intel)] on
win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import matplotlib
>>> matplotlib.use('TkAgg')
>>> from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python25\Lib\site-packages\matplotlib\backends\backend_tkagg.py",
line 8, in <module>
    import tkagg                 # Paint image to Tk photo blitter extension
  File "C:\Python25\lib\site-packages\matplotlib\backends\tkagg.py",
line 1, in <module>
    import _tkagg
ImportError: DLL load failed: The specified module could not be found.
>>>

I found one old (2004) post
http://mail.python.org/pipermail/python-list/2004-April/258963.html
that seems to indicate that some sort version mismatch of the Tk/Tcl
libraries may be to blame.  But I don't know how to diagnose that or
what to do about it.

FWIW, I installed using matplotlib-0.90.1.win32-py2.5.exe and
numpy-1.0.3.1.win32-py2.5.exe.

Thanks in advance for any help you can give me.
Sincerely,
~Simon

Dear matplotlib group,

for the represenation of 2d measurement data I use the contourplot function
from matplotlib. Some points in this map are not measurabel, therefore I get
a non numerical value (nan) output.

>From this data I want to generate a map and a histogram plot. This works
fine, as long as I use regular matrix/array data structure without any
voids.

My questions are:
(1) How can I make use of plotting data with NAN values as contour and
asigns such values eg as black points?
(2) How can I use the matplotlib hist() function with this data, that also
include such missing data points?
Maybe there is an easy workaround for this.

Thanks a  lot for your support,
Dirk

(python2.51/matplotlib-0.90.1, win32)

my code:
...
import matplotlib
...
my2dData=[[1,2,3,4,5.0 ,NaN,7,8,9,10],[10,9,8,7,6,5,4,3,2,1]]
...
figure(1)
imshow(my2dData)
pylab.show()
..

On 9/26/07, JeanMichel FRANCOIS <to...@gm...> wrote:
> Hi there!
>  I m trying to make a figure , adding a subplot in it, and then specify the X
> axis with date. I don't have anything to plot at the moment, i just want to
> generate a subplot with axes X and Y up and ready.
>
> All tutorials i have read directly plot sth on the subplot directly, but i
> don't want this in my software.
>
> here is an extract from my code
>
>   visitor.figure = pylab.figure(1)
>   visitor.figure.clear()
>   visitor.figure.set_dpi(self.context.getDPI())
>   visitor.figure.set_edgecolor(self.context.getEdgeColor())
>   visitor.figure.set_facecolor(self.context.getFaceColor())
>   visitor.figure.set_figheight(self.context.getSizeHeight())
>   visitor.figure.set_figwidth(self.context.getSizeWidth())
>   visitor.subplot = visitor.figure.add_subplot(111)
>   visitor.subplot.set_title(self.context.title)
>
> Then the user add his xaxis with parameters like xmin, xmax, step, ...
> But here i don't find how to setup this with pylab.
>
>   xaxis = subplot.get_xaxis()

xaxis = subplot.xaxis

> here i don't know how to proceed to set my array of values.
> I have an array of date.

You can plot your array of dates with :

  import matplotlib.dates as mdates
  l = ax.plot_date(mdates.date2num(mydates), y, 'k-')

Later you can modify the xlimits:

  subplot.set_xlim(mdates.date2num(datetime.date(2007,1,1)),
                          mdates.date2num(datetime.date(2007,7,1)))

or your plot data

  l.set_data(newdates, newy)

With recent versions of matplotlib, you can pas dates in directory to
plot and set_xlim and friends ( you don't need to convert them with
date2num).  Eg, with

  ax.plot(mydates, y)
  ax.set_xlim(datetime.date(2007,1,1), datetime.date(2007,7,1))
  fig.autofmt_xdate()

JDH

Hi there!
=A0 I m trying to make a figure , adding a subplot in it, and then specify =
the X=20
axis with date. I don't have anything to plot at the moment, i just want to=
=20
generate a subplot with axes X and Y up and ready.=20

All tutorials i have read directly plot sth on the subplot directly, but i=
=20
don't want this in my software.=20

here is an extract from my code

=A0 =A0 =A0 =A0 visitor.figure =3D pylab.figure(1)
=A0 =A0 =A0 =A0 visitor.figure.clear()
=A0 =A0 =A0 =A0 visitor.figure.set_dpi(self.context.getDPI())
=A0 =A0 =A0 =A0 visitor.figure.set_edgecolor(self.context.getEdgeColor())
=A0 =A0 =A0 =A0 visitor.figure.set_facecolor(self.context.getFaceColor())
=A0 =A0 =A0 =A0 visitor.figure.set_figheight(self.context.getSizeHeight())
=A0 =A0 =A0 =A0 visitor.figure.set_figwidth(self.context.getSizeWidth())
=A0 =A0 =A0 =A0 visitor.subplot =3D visitor.figure.add_subplot(111)
=A0 =A0 =A0 =A0 visitor.subplot.set_title(self.context.title)

Then the user add his xaxis with parameters like xmin, xmax, step, ...
But here i don't find how to setup this with pylab.

=A0 =A0 =A0 =A0 xaxis =3D subplot.get_xaxis()

here i don't know how to proceed to set my array of values.
I have an array of date.=20


JeanMichel FRANCOIS
=2D-=20
Cordialement,
JeanMichel FRANCOIS
Makina-Corpus

usetex=true IS supported for eps.  I use epstopdf to get pdf's from there.

Ryan

On 9/21/07, Jordan Atlas <jc...@co...> wrote:
>
> >Do you have ghostscript installed? If you set verbose.level to debug or
> >debug-annoying, what do you get?
> >
> >
> >
>
> I realized that the ghostscript path wasn't set up properly, so that was
> what was causing part of the problem with EPS files.  It works sometimes
> now (sometimes the EPS is just a blank file, even though the plot shows
> up properly when I do pylab.show().  I'm still trying to narrow down
> what ameks the difference here).
>
> >>I guess I mean TeX-like mathtext format parsed by matplotlib.  For
> >>example, I'm using things like this:
> >>
> >>rc('text', usetex=True)
> >>Plotting.xlabel(r'\textbf{Time (s)}', fontsize=16)
> >>
> >>
> >
> >usetex=True means that you are trying to use an external TeX program.
> >
> >
> >
>
> Ok, so am I to understand that usetex=True is not supported for PDF/EPS
> output?  Can you explain what the "Tex-like mathtext format parsed by
> matplotlib" is?
>
> Thank you for your assistance,
>
> --Jordan
>
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

The error message states that you must be using VS2003.  Python is
compiled with this, so all extensions must also be compiled with it.
If you don't have a copy of VS2003 your best bet is to just use
cygwin/mingw.

- Charlie

On 9/25/07, Michael Droettboom <md...@st...> wrote:
> You didn't mention which compiler you were trying to use.  It looks like
> it can't find the Microsoft compiler.  If you have it installed, perhaps
> it's installed in a non-standard location...?  It should be
> theoretically possible to use the free Microsoft compiler, but I have no
> experience with that.
>
> I have used the Mingw32 compiler included with Cygwin to build
> matplotlib recently with success.  There is also a version of Mingw32
> that is not part of Cygwin.  To use one of these compilers, you need to
> explicitly tell distutils (the system used to build matplotlib) to use
> it, using "-c mingw32".
>
> Cheers,
> Mike
>
> C M wrote:
> >
> > On 9/24/07, *John Hunter* < jd...@gm...
> > <mailto:jd...@gm...>> wrote:
> >
> >     On 9/24/07, C M <cmp...@gm... <mailto:cmp...@gm...>> wrote:
> >     >  I'm having problems building matplotlib on windows from a folder
> >     from SVN,
> >     >  and haven't done it
> >     >  before (previously had used the prebuilt binary download).  I
> >     don't know
> >     >  what I am doing wrong.
> >
> >     Read the header of setupext.py, particularly the part for win32 users
> >     -- it may not be totally current, but will get much you closer to your
> >     goal.  Once you have followed the steps there, if you hit another
> >     roadblock check back here and  we will advise further and try and
> >     update the docs as necessary.  You are actually in the best position
> >     to write documentation, since you are hitting this for the first time,
> >     so please take notes and/or update the instructions in setupext.py so
> >     we can add them to the docs.
> >
> >
> > Well, not familiar with this at all but giving it a try...In the
> > setupext.py
> > header it reads:
> >
> >   This build is similar to the mingw.  Download the visual studio static
> >   dependencies from
> >   http://matplotlib.sourceforge.net/win32_static_vs.tar.gz
> > <http://matplotlib.sourceforge.net/win32_static_vs.tar.gz> and
> >   see the README in that dir
> >
> > I did that.  Then, README there says:
> >
> >   Contents:
> >   Static dependencies for building mpl for win32 using
> >   Visual Studio.
> >   Extract to the matplotlib source folder.
> >
> > I extracted it to the matplotlib folder itself and also on another
> > try the subfolder, src.  In both cases then from cmd did:
> >
> >   python setup.py build bdist_wininst
> >
> > In both cases got same error as before.
> >
> > I like to be more help but I am not sure what to do.
> > It isn't crucial that I get the latest via SVN and
> > build it myself, but I thought it would be good to learn
> > to do this generally, just didn't realize it would be a bit
> > of an expedition.  Not sure what to do.
> >
> > Thanks.
> >
> >
> > ------------------------------------------------------------------------
> >
> > -------------------------------------------------------------------------
> > This SF.net email is sponsored by: Microsoft
> > Defy all challenges. Microsoft(R) Visual Studio 2005.
> > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> >
> >
> > ------------------------------------------------------------------------
> >
> > _______________________________________________
> > Matplotlib-users mailing list
> > Mat...@li...
> > https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
> --
> Michael Droettboom
> Operations and Engineering Division
> Space Telescope Science Institute
> Operated by AURA for NASA
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

You didn't mention which compiler you were trying to use.  It looks like 
it can't find the Microsoft compiler.  If you have it installed, perhaps 
it's installed in a non-standard location...?  It should be 
theoretically possible to use the free Microsoft compiler, but I have no 
experience with that.

I have used the Mingw32 compiler included with Cygwin to build 
matplotlib recently with success.  There is also a version of Mingw32 
that is not part of Cygwin.  To use one of these compilers, you need to 
explicitly tell distutils (the system used to build matplotlib) to use 
it, using "-c mingw32".

Cheers,
Mike

C M wrote:
> 
> On 9/24/07, *John Hunter* < jd...@gm... 
> <mailto:jd...@gm...>> wrote:
> 
>     On 9/24/07, C M <cmp...@gm... <mailto:cmp...@gm...>> wrote:
>     >  I'm having problems building matplotlib on windows from a folder
>     from SVN,
>     >  and haven't done it
>     >  before (previously had used the prebuilt binary download).  I
>     don't know
>     >  what I am doing wrong.
> 
>     Read the header of setupext.py, particularly the part for win32 users
>     -- it may not be totally current, but will get much you closer to your
>     goal.  Once you have followed the steps there, if you hit another
>     roadblock check back here and  we will advise further and try and
>     update the docs as necessary.  You are actually in the best position
>     to write documentation, since you are hitting this for the first time,
>     so please take notes and/or update the instructions in setupext.py so
>     we can add them to the docs.
> 
> 
> Well, not familiar with this at all but giving it a try...In the 
> setupext.py
> header it reads:
> 
>   This build is similar to the mingw.  Download the visual studio static
>   dependencies from
>   http://matplotlib.sourceforge.net/win32_static_vs.tar.gz 
> <http://matplotlib.sourceforge.net/win32_static_vs.tar.gz> and
>   see the README in that dir
> 
> I did that.  Then, README there says:
> 
>   Contents:
>   Static dependencies for building mpl for win32 using
>   Visual Studio.
>   Extract to the matplotlib source folder.
> 
> I extracted it to the matplotlib folder itself and also on another
> try the subfolder, src.  In both cases then from cmd did:
> 
>   python setup.py build bdist_wininst
> 
> In both cases got same error as before. 
> 
> I like to be more help but I am not sure what to do. 
> It isn't crucial that I get the latest via SVN and
> build it myself, but I thought it would be good to learn
> to do this generally, just didn't realize it would be a bit
> of an expedition.  Not sure what to do.
> 
> Thanks.
> 
> 
> ------------------------------------------------------------------------
> 
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

-- 
Michael Droettboom
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

I came across this piece by Adam Hupp on programming.reddit.com just 
now. It looks interesting:

http://hupp.org/adam/weblog/2007/09/03/etframes-applying-the-ideas-of-edward-tufte-to-matplotlib/ 

On 9/24/07, John Hunter <jd...@gm...> wrote:
>
> On 9/24/07, C M <cmp...@gm...> wrote:
> > I'm having problems building matplotlib on windows from a folder from
> SVN,
> > and haven't done it
> > before (previously had used the prebuilt binary download).  I don't know
>
> > what I am doing wrong.
>
> Read the header of setupext.py, particularly the part for win32 users
> -- it may not be totally current, but will get much you closer to your
> goal.  Once you have followed the steps there, if you hit another
> roadblock check back here and  we will advise further and try and
> update the docs as necessary.  You are actually in the best position
> to write documentation, since you are hitting this for the first time,
> so please take notes and/or update the instructions in setupext.py so
> we can add them to the docs.


Well, not familiar with this at all but giving it a try...In the setupext.py
header it reads:

  This build is similar to the mingw.  Download the visual studio static
  dependencies from
  http://matplotlib.sourceforge.net/win32_static_vs.tar.gz and
  see the README in that dir

I did that.  Then, README there says:

  Contents:
  Static dependencies for building mpl for win32 using
  Visual Studio.
  Extract to the matplotlib source folder.

I extracted it to the matplotlib folder itself and also on another
try the subfolder, src.  In both cases then from cmd did:

  python setup.py build bdist_wininst

In both cases got same error as before.

I like to be more help but I am not sure what to do.
It isn't crucial that I get the latest via SVN and
build it myself, but I thought it would be good to learn
to do this generally, just didn't realize it would be a bit
of an expedition.  Not sure what to do.

Thanks.

On 9/24/07, C M <cmp...@gm...> wrote:
> I'm having problems building matplotlib on windows from a folder from SVN,
> and haven't done it
> before (previously had used the prebuilt binary download).  I don't know
> what I am doing wrong.

Read the header of setupext.py, particularly the part for win32 users
-- it may not be totally current, but will get much you closer to your
 goal.  Once you have followed the steps there, if you hit another
roadblock check back here and  we will advise further and try and
update the docs as necessary.  You are actually in the best position
to write documentation, since you are hitting this for the first time,
so please take notes and/or update the instructions in setupext.py so
we can add them to the docs.

Thanks,
JDH

I'm having problems building matplotlib on windows from a folder from SVN,
and haven't done it
before (previously had used the prebuilt binary download).  I don't know
what I am doing wrong.
I'm on winXP, Python 2.5. and will be using wxPython 2.8.4.2 with matplotlib
as well.

The folder with the contents from SVN I've named matplotlib_svn.  From the
cmd line and
while in that directory I wrote

python setup.py build

and got what follows.  I'm not sure what I am to do (regarding finding an
appropriate
compiler).  Any help is appreciated.


C:\Python25\Lib\site-packages\matplotlib_svn>python setup.py build
============================================================================
BUILDING MATPLOTLIB
            matplotlib: 0.90.1
                python: 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310
                        32 bit (Intel)]
              platform: win32
       Windows version: (5, 1, 2600, 2, 'Service Pack 2')

REQUIRED DEPENDENCIES
                 numpy: 1.0
             freetype2: found, but unknown version (no pkg-config)
                        * WARNING: Could not find 'freetype2' headers in any
                        * of '.', '.\freetype2'.

OPTIONAL DEPENDENCIES
                  Gtk+: no
                        * Building for Gtk+ requires pygtk; you must be able
                        * to "import gtk" in your build/install environment
               Tkinter: Tkinter: 50704, Tk: 8.4, Tcl: 8.4
                        * Tkinter present, but header files are not
                        * installed.  You may need to install development
                        * packages.
              wxPython: 2.8.4.2
                        * WxAgg extension not required for wxPython >= 2.8
                    Qt: no
                   Qt4: no
                 Cairo: no
                libpng: found, but unknown version (no pkg-config)
                        * Could not find 'libpng' headers in any of '.'

[Edit setup.cfg to suppress the above messages]
============================================================================
running build
running build_py
copying lib\matplotlib\mpl-data\matplotlibrc -> build\lib.win32-
2.5\matplotlib\m
pl-data
running build_ext
No module named msvccompiler in numpy.distutils, trying from distutils..
error: Python was built with Visual Studio 2003;
extensions must be built with a compiler than can generate compatible
binaries.
Visual Studio 2003 was not found on this system. If you have Cygwin
installed,
you can try compiling with MingW32, by passing "-c mingw32" to setup.py.

Perry Greenfield wrote:
> On Sep 24, 2007, at 2:32 PM, Tommy Grav wrote:
> 
>> I need to generate a set of histograms, but would like to plot only
>> the "skyline"
>> of the histogram, and leave out the vertical lines where adjencent
>> bars touch.
>> I have looked at the docs, but nothing jumped out at me as the right
>> keyword
>> for this. Is this possible? and if so, how?
> 
> I believe that you can do the same thing using the regular plot  
> command with linestyles='steps' (but I think you need to fiddle with  
> the x values so that the steps are aligned properly. But it would be  
> nice if hist could do this too.

There is also an axes step() method in svn.

Eric

I wrote the following code to do this for me...it is not entirely general 
(in the sense that it doesn't accept all kwargs beyond bins and hatch) and 
also allows me to do my own normalization.... But you should be able to 
use it pretty easily.


def open_hist(arr,bins=10,norm=None,hatch=None):
         import matplotlib as mpl
         import pylab

         # Get all of the scaling right by allowing pylab to do it.
         d = pylab.hist(arr,bins)
         ax = pylab.gca()
         for i in d[2]:
                 ax.patches.remove(i)
         width = d[1][1]-d[1][0]

         if norm is None:
                 norm = 1.
         else:
                 norm = float(norm)
         # Determine the vertices of the no-line histogram.
         verts = []
         for i in range(len(d[0])):
                 if i==0:
                         x = d[1][i]
                         y = 0.
                         verts.append((x,y))
                 if i==len(d[0])-1:
                         x = d[1][i]
                         y = d[0][i]/norm
                         verts.append((x,y))
                         x = d[1][i]+width
                         verts.append((x,y))
                         y = 0.
                         verts.append((x,y))
                 else:
                         x = d[1][i]
                         y = d[0][i]/norm
                         verts.append((x,y))
                         x = d[1][i]+width
                         verts.append((x,y))

         # Let pylab do its thing....
         p = pylab.Polygon(verts,transform=ax.transData,hatch=hatch)
         p.set_fill(0)
         ax.add_patch(p)




On Mon, 24 Sep 2007, Tommy Grav wrote:

> I need to generate a set of histograms, but would like to plot only
> the "skyline"
> of the histogram, and leave out the vertical lines where adjencent
> bars touch.
> I have looked at the docs, but nothing jumped out at me as the right
> keyword
> for this. Is this possible? and if so, how?
>
> Cheers
>   Tommy
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

On Sep 24, 2007, at 2:32 PM, Tommy Grav wrote:

> I need to generate a set of histograms, but would like to plot only
> the "skyline"
> of the histogram, and leave out the vertical lines where adjencent
> bars touch.
> I have looked at the docs, but nothing jumped out at me as the right
> keyword
> for this. Is this possible? and if so, how?

I believe that you can do the same thing using the regular plot  
command with linestyles='steps' (but I think you need to fiddle with  
the x values so that the steps are aligned properly. But it would be  
nice if hist could do this too.

Perry

I need to generate a set of histograms, but would like to plot only  
the "skyline"
of the histogram, and leave out the vertical lines where adjencent  
bars touch.
I have looked at the docs, but nothing jumped out at me as the right  
keyword
for this. Is this possible? and if so, how?

Cheers
   Tommy

Mike,

pcolor has had masked array support for a long time.  Please send a 
minimal but complete example of a script that fails; based on what you 
sent below, I can't tell what the problem is.

Eric

Mike Bauer wrote:
> Howdy,
> 
> I'm a recent refugee from GMT (Generic Mapping Tools) and am very happy 
> to have found matplotlib.
> 
> I've been having one nagging issue however that I must resolve as I 
> require this ability. Basically, I need to mask 2d arrays and plot the 
> result with pcolor via basemap.
> 
>  From the documentation it seems this should be fairly straight forward 
> and I'm hoping that this is the case.
> 
> Here is an example of problem.
> -------------------------------------------
> from pylab import *
> import matplotlib.numerix.ma <http://matplotlib.numerix.ma> as ma # 
> matplotlibrc has numerix : numpy
> from matplotlib.toolkits.basemap import Basemap, shiftgrid, addcyclic
> import numpy as N
> .
> .
> .
> 
> im = 144
> jm = 93
> lons  = N.array([0., ...  357.5],dtype=float)
> lats =  N.array([-90., ... 90.],dtype=float)
> topo_screen = N.zeros((jm,im),dtype='float')
> topo_screen[10] = 1
> new_test = 100.* N.ones((jm,im),dtype='float')
> masked_test = ma.masked_where(topo_screen,new)
> 
> This works and a screen dump of masked_test seem correct.
> 
> A call to pcolor however results in the following:
> matplotlib version 0.90.1
> verbose.level helpful
> interactive is False
> units is True
> platform is linux2
> numerix numpy 1.0.1
> .
> .
> .
> /usr/local/lib/python2.5/site-packages/numpy/core/ma.py:604: 
> UserWarning: Cannot automatically convert masked array to numeric 
> because data is masked in one or more locations.
> -------------------------------------------
> 
> Is this an embarrassingly simple error on my part? I hope so. Any help 
> would be much appreciated.
> 
> Mike
> 
> 
> ------------------------------------------------------------------------
> 
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

Howdy,

I'm a recent refugee from GMT (Generic Mapping Tools) and am very happy to
have found matplotlib.

I've been having one nagging issue however that I must resolve as I require
this ability. Basically, I need to mask 2d arrays and plot the result with
pcolor via basemap.

>From the documentation it seems this should be fairly straight forward and
I'm hoping that this is the case.

Here is an example of problem.
-------------------------------------------
from pylab import *
import matplotlib.numerix.ma as ma # matplotlibrc has numerix : numpy
from matplotlib.toolkits.basemap import Basemap, shiftgrid, addcyclic
import numpy as N
.
.
.

im = 144
jm = 93
lons  = N.array([0., ...  357.5],dtype=float)
lats =  N.array([-90., ... 90.],dtype=float)
topo_screen = N.zeros((jm,im),dtype='float')
topo_screen[10] = 1
new_test = 100.*N.ones((jm,im),dtype='float')
masked_test = ma.masked_where(topo_screen,new)

This works and a screen dump of masked_test seem correct.

A call to pcolor however results in the following:
matplotlib version 0.90.1
verbose.level helpful
interactive is False
units is True
platform is linux2
numerix numpy 1.0.1
.
.
.
/usr/local/lib/python2.5/site-packages/numpy/core/ma.py:604: UserWarning:
Cannot automatically convert masked array to numeric because data is masked
in one or more locations.
-------------------------------------------

Is this an embarrassingly simple error on my part? I hope so. Any help would
be much appreciated.

Mike

Howdy,

I'm a recent refugee from GMT (Generic Mapping Tools) and am very  
happy to have found matplotlib.

I've been having one nagging issue however that I must resolve as I  
require this ability. Basically, I need to mask 2d arrays and plot  
the result with pcolor via basemap.

 From the documentation it seems this should be fairly straight  
forward and I'm hoping that this is the case.

Here is an example of problem.
-------------------------------------------
from pylab import *
import matplotlib.numerix.ma as ma # matplotlibrc has numerix : numpy
from matplotlib.toolkits.basemap import Basemap, shiftgrid, addcyclic
import numpy as N
.
.
.

im = 144
jm = 93
lons  = N.array([0., ...  357.5],dtype=float)
lats =  N.array([-90., ... 90.],dtype=float)
topo_screen = N.zeros((jm,im),dtype='float')
topo_screen[10] = 1
new_test = 100.*N.ones((jm,im),dtype='float')
masked_test = ma.masked_where(topo_screen,new)

This works and a screen dump of masked_test seem correct.

A call to pcolor however results in the following:
matplotlib version 0.90.1
verbose.level helpful
interactive is False
units is True
platform is linux2
numerix numpy 1.0.1
.
.
.
/usr/local/lib/python2.5/site-packages/numpy/core/ma.py:604:  
UserWarning: Cannot automatically convert masked array to numeric  
because data is masked in one or more locations.
-------------------------------------------

Is this an embarrassingly simple error on my part? I hope so. Any  
help would be much appreciated.

Mike

Hi all,
I want to plot an irregular grid of points with x coordinates that can assume 
values between 0 and 13216 and  y coordinates that can assume values between 
0 and 8985 on a transparent canvas and save it as a .png file.
I use Agg backend.
I would like than to superimpose the obtained .png image over another image 
(not obtained with matplotlib and not with python) of 13217 x 8986 pixels.
This because the irregular grid points of the first image are pixels of the 
second image. 
I have write this script where 

samples = 13217 
lines = 8986 
dpi = 100
xvect and yvect 2 numpy vectors that i have to convert to lists.


# data aspect ratio
data_aspect_ratio = samples / float(lines)
# figure axis inches dimension
x_axis_inches = lines / float(dpi)
y_axis_inches = data_aspect_ratio * x_axis_inches
# drawing figure canvas
figure_label = p.figure(facecolor = 'w', edgecolor = 'w', 
figsize=(x_axis_inches, y_axis_inches), frameon = False)
# main axes enlarging to fill all vanvas
main_axes = p.axes([0, 0, 1, 1])
# plot grid
points_1 = p.plot(xvect.tolist(), yvect.tolist(), 'D')
# grid setting properties
p.setp(points_1, markersize = 30, markeredgecolor = 'b', markerfacecolor 
= 'None', markeredgewidth = 7)
main_axes.axis([0, lines, 0, samples])
# transparence
main_axes.axesPatch.set_alpha(0.0)
# deleting asix ticks
p.setp(main_axes, xticks = [], yticks = [])
# reversing y axis
y_reversing = main_axes.set_ylim(main_axes.get_ylim()[::-1])
# image saving
p.savefig(out_image_file, dpi = dpi)
# closing figure
p.close(figure_label)

The problem is that i obtain a .png image of 13216 x 8985 pixels and not of 
13217 x 8986 pixels as i planned. What can it be the problem ?
Thank you all.

-- 
--
Emanuele Passera