matplotlib-users Mailing List for matplotlib

Filipe Pires Alvarenga Fernandes <ocefpaf@...> writes:
> 
> Yep, that's what I was expecting. It should fail with both show() and
> the save as 'png' format. However, it only fails when trying to save
> an 'eps'
> 
> -Filipe
> 
> On Mon, May 7, 2012 at 1:12 PM, Benjamin Root <ben.root <at> ou.edu> 
wrote:
> > On Mon, May 7, 2012 at 12:55 PM, Michael Droettboom <mdroe <at> 
stsci.edu> wrote:
> >>
> >> That's not a bug. linewidth is required to be a float, rather than a
> >> string. Python's typing is generally a little stricter than languages
> >> such as JavaScript.
> >>
> >> Mike
> >>
> >
> > I think the bigger question is why does it _work_ with show()? I would
> > expect it to fail. I would rather have it fail everywhere or work
> > everywhere.
> >
> > Ben Root
> >
> >
> >
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> 
I came upon this thread after a lot of time messing with savefig. I was 
trying to get images in some vector format and was specifying linewidth as a 
string. Thanks to this thread, I have my images. However, some things I 
noticed were:
(1) This error message only appeared when I tried to save as eps; not for 
pdf (my preference) or svg.
(2) Shouldn't the exception or warning be raised when the plot call is made 
(for me it was bar(...)) ?
(3) using pdf and svg with savefig raised no error. However, the resulting 
images were corrupted. Weirdly, in the case of pdf, the only pdf reader I 
tried not able to render the image correctly was adobe acrobat. Even the 
browser plugin for adobe could do it. In the case of svg, I opened the image 
in imagemagick but it did not look much like it should have.

I've been converting my code that used nxutils.points_inside_poly (for checking if a point is inside a polygon) to instead use path.contains_points (since the former is now deprecated).
After reading the docs about creating Path objects, I thought I understood that I needed to supply the first vertex of the polygon twice - at the start of the array and at the end of the array, and that I needed to set the 'closed' argument to True in order to get the Path for a polygon.
But when I created Paths like that, I always seemed to get an array of all False's from path.contains_points.
Looking at the source code for the nxutils.points_inside_poly wrapper, I see that it creates Path's by just passing the polygon vertices (without the extra vertex at the end) and without the 'closed' flag. And the Path's created this way work correctly with path.contains_points.
Here's example code:
verts1 = [(0,0), (0,1), (1,1), (1,0)]
verts2 = [(0,0), (0,1), (1,1), (1,0), (0,0)]
path1 = Path(verts1)
path2 = Path(verts2, closed=True)
>>> path1
Path([[ 0. 0.]
 [ 0. 1.]
 [ 1. 1.]
 [ 1. 0.]], None)
>>> path2
Path([[ 0. 0.]
 [ 0. 1.]
 [ 1. 1.]
 [ 1. 0.]
 [ 0. 0.]], [ 1 2 2 2 79])
points = [(0.5,0.5), (1.5,0.5)]
>>> path1.contains_points(points)
array([ True, False], dtype=bool)
>>> path2.contains_points(points)
array([False, False], dtype=bool)
The problem seems to occur when some of the points are inside and some are not.
If all of the points are inside, it works fine:
points = [(0.5,0.5), (0.51,0.51)]
>>> path2.contains_points(points)
array([ True, True], dtype=bool)
--
Cameron Hayne
cam...@gm...

On 2013年04月26日 08:31, Sterling Smith wrote:
 > Notwithstanding these probably work (I haven't tried), my gut
reaction would have been to color the edges the same as the face,
although I don't know if you can give set_edgecolor the same
cmap(colors_norm) argument.
	I think you can set the edgecolor equal to the string 'face' to make 
it use the facecolor.
-- 
Brendan Barnwell
"Do not follow where the path may lead. Go, instead, where there is 
no path, and leave a trail."
 --author unknown

Hi Mat,
On Apr 26, 2013, at 3:03 AM, Mathew Topper <mat...@ed...> wrote:
> I have a set of wave directions in lon lat,
Not clear how a direction is given as a lon lat. Do you mean you have a set of vectors, each defined as lon/lat pairs? 
> but I want to display them 
> in a UTM type projection. I believe the directions will be distorted, 
> but I'm not sure by how much.
It depends on what you want - if you want the arrow to point where the wind would go after X minutes, then you want the "distortion". If you want the viewer to be able to pick off the geographic heading by eye, then simply convert your lon lat pairs to heading/length pairs and plot them in the axis frame. See http://matplotlib.org/basemap/users/mapcoords.html for how to convert from basemap to the underlying axis frame.
In an ideal world your projection would not be over such a large area that any of this matters - if your vector is off by 1 degree, who will be able to tell in a plot? 
Cheers, Jody
--
Jody Klymak 
http://web.uvic.ca/~jklymak/

2013年4月26日 Chad Parker <par...@gm...>
> Hi all-
>
> I've been working on a plot that puts the bottom and right spines at zero
> (adapting some code from the example at
> http://matplotlib.org/examples/pylab_examples/spine_placement_demo.html)
> , and I've discovered that setting the position of the right spine to
> 'zero' seems to locate it at x=1.
>
> Is this a bug? Or is there something that I'm missing?
>
It looks like a bug to me, set_position('data', x) puts the spine at x + 1
instead of x.
Goyo

Ryan,
thank you very much, it works and it's exaclty how I needed it to look like!
Cheers,

Notwithstanding these probably work (I haven't tried), my gut reaction would have been to color the edges the same as the face, although I don't know if you can give set_edgecolor the same cmap(colors_norm) argument.
-Sterling
On Apr 26, 2013, at 5:30AM, Ryan Nelson wrote:
> Hackstein,
> 
> Francesco's suggestion works for me.
> col.set_edgecolor( 'none' )
> 
> You can also set the linewidth to be 0.
> col.set_linewidth( 0 )

On 04/26/2013 02:57 AM, Werner F. Bruhin wrote:
> Hi,
>
> Anyone can provide some info on what "agg.buffer_rgba" returns and maybe
> even some suggestion on how to resolve this issue in the wxagg backend.
It returns a Python buffer object on Python 2, though on Python 3 it is 
a memoryview, since buffer was deprecated. Perhaps wx is also doing 
something different depending on the version of Python.
>
> Thanks
> Werner
>
> P.S.
> The archive on Sourceforge for this list stops in June 2012, noticed
> this as I wanted to check if there are answers I didn't get for some reason.
> http://sourceforge.net/mailarchive/forum.php?forum_name=matplotlib-users
Yeah -- I've reported that to sourceforge many times. Not sure what the 
issue is. Personally, I use gmane when I need to search the archive and 
it works rather well.
Mike
>
> On 20/04/2013 08:58, Werner F. Bruhin wrote:
>> Hi,
>>
>> I am trying to get matplotlib 1.2.0 to work with wxPython Phoenix - will
>> provide a patch when it is working.
>>
>> Made the changes to backend_wx* for things like EmptyImage/EmptyBitmap
>> and Toolbar but I am stuck on the following.
>>
>> if bbox is None:
>> # agg => rgba buffer -> bitmap
>> if 'phoenix' in wx.PlatformInfo:
>> return wx.Bitmap.FromBufferRGBA(int(agg.width),
>> int(agg.height),
>> memoryview(agg.buffer_rgba()))
>> else:
>> return wx.BitmapFromBufferRGBA(int(agg.width), int(agg.height),
>> agg.buffer_rgba())
>> else:
>> # agg => rgba buffer -> bitmap => clipped bitmap
>> return _WX28_clipped_agg_as_bitmap(agg, bbox)
>>
>> TypeError: cannot make memory view because object does not have the
>> buffer interface
>> File "h:\devProjectsT\aaTests\matplotlib\wxembedding-5.py", line 63, in
>> <module>
>> demo()
>> File "h:\devProjectsT\aaTests\matplotlib\wxembedding-5.py", line 60, in demo
>> app.MainLoop()
>> File "c:\Python27\Lib\site-packages\wx-2.9.6-msw-phoenix\wx\core.py",
>> line 1841, in MainLoop
>> rv = wx.PyApp.MainLoop(self)
>> File "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wx.py",
>> line 1209, in _onPaint
>> self.draw(drawDC=drawDC)
>> File
>> "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wxagg.py",
>> line 61, in draw
>> self.bitmap = _convert_agg_to_wx_bitmap(self.get_renderer(), None)
>> File
>> "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wxagg.py",
>> line 173, in _convert_agg_to_wx_bitmap
>> memoryview(agg.buffer_rgba()))
>>
>> I tried using "memoryview" based on a suggestion by Robin Dunn, and
>> based on the following info I see in the debugger that should work no?
>>
>> agg.buffer_rgba()
>> <read-write buffer ptr 0x05400638, size 229200 at 0x055FC680>
>> type(agg.buffer_rgba())
>> <type 'buffer'>
>> agg
>> <matplotlib.backends.backend_agg.RendererAgg instance at 0x04BA0670>
>>
>> If I don't use "memoryview" (which would probably be preferred) I get
>> the following exception.
>>
>> Can someone help us figure this one out.
>>
>> Thanks
>> Werner
>>
>>
>> TypeError: Bitmap.FromBufferRGBA(): argument 3 has unexpected type 'buffer'
>> File "h:\devProjectsT\aaTests\matplotlib\wxembedding-5.py", line 63, in
>> <module>
>> demo()
>> File "h:\devProjectsT\aaTests\matplotlib\wxembedding-5.py", line 60, in demo
>> app.MainLoop()
>> File "c:\Python27\Lib\site-packages\wx-2.9.6-msw-phoenix\wx\core.py",
>> line 1841, in MainLoop
>> rv = wx.PyApp.MainLoop(self)
>> File "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wx.py",
>> line 1209, in _onPaint
>> self.draw(drawDC=drawDC)
>> File
>> "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wxagg.py",
>> line 61, in draw
>> self.bitmap = _convert_agg_to_wx_bitmap(self.get_renderer(), None)
>> File
>> "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wxagg.py",
>> line 173, in _convert_agg_to_wx_bitmap
>> agg.buffer_rgba())
>>
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Hackstein,
Francesco's suggestion works for me.
col.set_edgecolor( 'none' )
You can also set the linewidth to be 0.
col.set_linewidth( 0 )
Colorbars in these cases can be more painful than you might like. You 
need to make a mappable object and pass that into a figure.colorbar 
call. Rather than try to explain it in detail, I've just pasted a 
modified version of my first script that should do what you need.
Glad we're getting closer.
Ryan
########################
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import Rectangle
from matplotlib.collections import PatchCollection
n = 100
# Get your xy data points, which are the centers of the rectangles.
xy = np.random.rand(n,2)
# Set a fixed height
height = 0.02
# The variable widths of the rectangles
widths = np.random.rand(n)*0.1
# Get a color map and make some colors
cmap = plt.cm.hsv
colors = np.random.rand(n)*10.
# Make a normalized array of colors
colors_norm = colors/colors.max()
# Here's where you have to make a ScalarMappable with the colormap
mappable = plt.cm.ScalarMappable(cmap=cmap)
# Give it your non-normalized color data
mappable.set_array(colors)
rects = []
for p, w in zip(xy, widths):
 xpos = p[0] - w/2 # The x position will be half the width from the 
center
 ypos = p[1] - height/2 # same for the y position, but with height
 rect = Rectangle( (xpos, ypos), w, height ) # Create a rectangle
 rects.append(rect) # Add the rectangle patch to our list
# Create a collection from the rectangles
col = PatchCollection(rects)
# set the alpha for all rectangles
col.set_alpha(0.3)
# Set the colors using the colormap
col.set_facecolor( cmap(colors_norm) )
# No lines
col.set_linewidth( 0 )
#col.set_edgecolor( 'none' )
# Make a figure and add the collection to the axis.
fig = plt.figure()
ax = fig.add_subplot(111)
ax.add_collection(col)
# Add your ScalarMappable to a figure colorbar
fig.colorbar(mappable)
plt.show()
########################
On 4/26/2013 7:15 AM, Hackstein wrote:
> Thanks, Ryan, this is (amost) exactly what I was looking for. Now, I get the markers and their colors right, but I still have two problems:
> The markers have a black edges, that I cannot get rid of. I've tried
>
> rect = Rectangle(..., ec=None)
>
> and also
>
> col.set=edgecolor(None)
>
> and 'None', respectively, both with no effect whatsoever.
>
> The second problem is, that I cannot get the colorbar to work.
> I tried
>
> sc = ax.add_collection(col)
> plt.colorbar(sc)
>
> and
>
> plt.colobar(col)
>
> both do not work.
> Any Ideas how to fix those two issues?
>
> Thanks,
>
> -Hackstein
>
>
>> Message: 4
>> Date: 2013年4月25日 19:44:23 -0400
>> From: Ryan Nelson <rne...@gm...>
>> Subject: Re: [Matplotlib-users] Individual custom markers and colorbar
>> To: mat...@li...
>> Message-ID: <517...@gm...>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> Hackstein,
>>
>> Unfortunately, I'm not sure of an 'elegant' way to do what your asking
>> with a single call to scatter. Others may know a better way. However,
>> you can use rectangle patches and patch collections. (Requires a bit
>> more code than scatter but is ultimately more flexible.)
>>
>> I think the example below does what you need, but with random numbers.
>>
>> Hope it helps a little.
>>
>> Ryan
>>
>> #######################
>> import numpy as np
>> import matplotlib.pyplot as plt
>> from matplotlib.patches import Rectangle
>> from matplotlib.collections import PatchCollection
>>
>> n = 100
>>
>> # Get your xy data points, which are the centers of the rectangles.
>> xy = np.random.rand(n,2)
>>
>> # Set a fixed height
>> height = 0.02
>> # The variable widths of the rectangles
>> widths = np.random.rand(n)*0.1
>>
>> # Get a color map and color values (normalized between 0 and 1)
>> cmap = plt.cm.jet
>> colors = np.random.rand(n)
>>
>> rects = []
>> for p, w, c in zip(xy, widths, colors):
>> xpos = p[0] - w/2 # The x position will be half the width from the
>> center
>> ypos = p[1] - height/2 # same for the y position, but with height
>> rect = Rectangle( (xpos, ypos), w, height ) # Create a rectangle
>> rects.append(rect) # Add the rectangle patch to our list
>>
>> # Create a collection from the rectangles
>> col = PatchCollection(rects)
>> # set the alpha for all rectangles
>> col.set_alpha(0.3)
>> # Set the colors using the colormap
>> col.set_facecolor( cmap(colors) )
>>
>> # Make a figure and add the collection to the axis.
>> ax = plt.subplot(111)
>> ax.add_collection(col)
>> plt.show()
>>
>> ###############################
>>
>>
>> On 4/24/2013 5:35 PM, Hackstein wrote:
>>> Hi all,
>>>
>>> I am trying to get a scatter plot using a colormap. Additionally, I
>>> need to define every marker for every data point individually -- each
>>> being a rectangle with fixed height but varying width as a function of
>>> the y-value. X and y being the data coordinates, z being a number to
>>> be color coded with the colormap.
>>>
>>> Ideally, I would like to create a list of width and height values for
>>> each data point and tell the scatter plot to use those.
>>>
>>> So far I got colormapped data with custom markers (simplified):
>>>
>>> [code]
>>>
>>> import numpy as np
>>>
>>> import matplotlib.pyplot as plt
>>>
>>> from pylab import *
>>>
>>> x = y = [1,2,3,4,5]
>>>
>>> z = [2,4,6,8,10]
>>>
>>> colors = cm.gnuplot2
>>>
>>> verts_vec = list(zip([-10.,10.,10.,-10.],[-5.,-5.,5.,5.]))
>>>
>>> fig = plt.figure(1, figsize=(14.40, 9.00))
>>>
>>> ax = fig.add_subplot(1,1,1)
>>>
>>> sc = ax.scatter(x, y, c=np.asarray(z), marker=None, edgecolor='None',
>>> verts=verts_vec, cmap=colors, alpha=1.)
>>>
>>> plt.colorbar(sc, orientation='horizontal')
>>>
>>> plt.savefig('test.png', dpi=200)
>>>
>>> plt.close(1)
>>>
>>> [/code]
>>>
>>> But I need to define a marker size for each point, and I also need to
>>> do that in axis scale values, not in points.
>>>
>>> I imagine giving verts a list of N*2 tuples instead of 2 tuples, N
>>> being len(x), to define N individual markers.
>>>
>>> But when doing that I get the error that vertices.ndim==2.
>>>
>>> A less elegant way would be to plot every data point in an individual
>>> scatter plot function, using a for-loop iterating over all data
>>> points. Then, however, I see no way to apply a colormap and colorbar.
>>>
>>> What is the best way to accomplish that then?
>>>
>>> Thanks,
>>>
>>> -Hackstein
>>>
>>>
>>>
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Thanks, Francesco, but I already tried for both and that doesn't work either.
Cheers,
Am 26.04.2013 um 14:07 schrieb Francesco Montesano <fra...@gm...>:
> 
> Il giorno 26/apr/2013 13:16, "Hackstein" <new...@gm...> ha scritto:
> >
> > Thanks, Ryan, this is (amost) exactly what I was looking for. Now, I get the markers and their colors right, but I still have two problems:
> > The markers have a black edges, that I cannot get rid of. I've tried
> >
> > rect = Rectangle(..., ec=None)
> >
> > and also
> >
> > col.set=edgecolor(None)
> 
> I think that you have to use the string 'none' instead of None type. The latter is used to use the default value for the variable (in you case black).
> 
> cheers
> Francesco
> >
> > and 'None', respectively, both with no effect whatsoever.
> >
> > The second problem is, that I cannot get the colorbar to work.
> > I tried
> >
> > sc = ax.add_collection(col)
> > plt.colorbar(sc)
> >
> > and
> >
> > plt.colobar(col)
> >
> > both do not work.
> > Any Ideas how to fix those two issues?
> >
> > Thanks,
> >
> > -Hackstein
> >
> >
> > > Message: 4
> > > Date: 2013年4月25日 19:44:23 -0400
> > > From: Ryan Nelson <rne...@gm...>
> > > Subject: Re: [Matplotlib-users] Individual custom markers and colorbar
> > > To: mat...@li...
> > > Message-ID: <517...@gm...>
> > > Content-Type: text/plain; charset="iso-8859-1"
> > >
> > > Hackstein,
> > >
> > > Unfortunately, I'm not sure of an 'elegant' way to do what your asking
> > > with a single call to scatter. Others may know a better way. However,
> > > you can use rectangle patches and patch collections. (Requires a bit
> > > more code than scatter but is ultimately more flexible.)
> > >
> > > I think the example below does what you need, but with random numbers.
> > >
> > > Hope it helps a little.
> > >
> > > Ryan
> > >
> > > #######################
> > > import numpy as np
> > > import matplotlib.pyplot as plt
> > > from matplotlib.patches import Rectangle
> > > from matplotlib.collections import PatchCollection
> > >
> > > n = 100
> > >
> > > # Get your xy data points, which are the centers of the rectangles.
> > > xy = np.random.rand(n,2)
> > >
> > > # Set a fixed height
> > > height = 0.02
> > > # The variable widths of the rectangles
> > > widths = np.random.rand(n)*0.1
> > >
> > > # Get a color map and color values (normalized between 0 and 1)
> > > cmap = plt.cm.jet
> > > colors = np.random.rand(n)
> > >
> > > rects = []
> > > for p, w, c in zip(xy, widths, colors):
> > > xpos = p[0] - w/2 # The x position will be half the width from the
> > > center
> > > ypos = p[1] - height/2 # same for the y position, but with height
> > > rect = Rectangle( (xpos, ypos), w, height ) # Create a rectangle
> > > rects.append(rect) # Add the rectangle patch to our list
> > >
> > > # Create a collection from the rectangles
> > > col = PatchCollection(rects)
> > > # set the alpha for all rectangles
> > > col.set_alpha(0.3)
> > > # Set the colors using the colormap
> > > col.set_facecolor( cmap(colors) )
> > >
> > > # Make a figure and add the collection to the axis.
> > > ax = plt.subplot(111)
> > > ax.add_collection(col)
> > > plt.show()
> > >
> > > ###############################
> > >
> > >
> > > On 4/24/2013 5:35 PM, Hackstein wrote:
> > >>
> > >> Hi all,
> > >>
> > >> I am trying to get a scatter plot using a colormap. Additionally, I
> > >> need to define every marker for every data point individually -- each
> > >> being a rectangle with fixed height but varying width as a function of
> > >> the y-value. X and y being the data coordinates, z being a number to
> > >> be color coded with the colormap.
> > >>
> > >> Ideally, I would like to create a list of width and height values for
> > >> each data point and tell the scatter plot to use those.
> > >>
> > >> So far I got colormapped data with custom markers (simplified):
> > >>
> > >> [code]
> > >>
> > >> import numpy as np
> > >>
> > >> import matplotlib.pyplot as plt
> > >>
> > >> from pylab import *
> > >>
> > >> x = y = [1,2,3,4,5]
> > >>
> > >> z = [2,4,6,8,10]
> > >>
> > >> colors = cm.gnuplot2
> > >>
> > >> verts_vec = list(zip([-10.,10.,10.,-10.],[-5.,-5.,5.,5.]))
> > >>
> > >> fig = plt.figure(1, figsize=(14.40, 9.00))
> > >>
> > >> ax = fig.add_subplot(1,1,1)
> > >>
> > >> sc = ax.scatter(x, y, c=np.asarray(z), marker=None, edgecolor='None',
> > >> verts=verts_vec, cmap=colors, alpha=1.)
> > >>
> > >> plt.colorbar(sc, orientation='horizontal')
> > >>
> > >> plt.savefig('test.png', dpi=200)
> > >>
> > >> plt.close(1)
> > >>
> > >> [/code]
> > >>
> > >> But I need to define a marker size for each point, and I also need to
> > >> do that in axis scale values, not in points.
> > >>
> > >> I imagine giving verts a list of N*2 tuples instead of 2 tuples, N
> > >> being len(x), to define N individual markers.
> > >>
> > >> But when doing that I get the error that vertices.ndim==2.
> > >>
> > >> A less elegant way would be to plot every data point in an individual
> > >> scatter plot function, using a for-loop iterating over all data
> > >> points. Then, however, I see no way to apply a colormap and colorbar.
> > >>
> > >> What is the best way to accomplish that then?
> > >>
> > >> Thanks,
> > >>
> > >> -Hackstein
> > >>
> > >>
> > >>
> > >> ------------------------------------------------------------------------------
> > >> Try New Relic Now & We'll Send You this Cool Shirt
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> > >>
> > >>
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Il giorno 26/apr/2013 13:16, "Hackstein" <new...@gm...> ha
scritto:
>
> Thanks, Ryan, this is (amost) exactly what I was looking for. Now, I get
the markers and their colors right, but I still have two problems:
> The markers have a black edges, that I cannot get rid of. I've tried
>
> rect = Rectangle(..., ec=None)
>
> and also
>
> col.set=edgecolor(None)
I think that you have to use the string 'none' instead of None type. The
latter is used to use the default value for the variable (in you case
black).
cheers
Francesco
>
> and 'None', respectively, both with no effect whatsoever.
>
> The second problem is, that I cannot get the colorbar to work.
> I tried
>
> sc = ax.add_collection(col)
> plt.colorbar(sc)
>
> and
>
> plt.colobar(col)
>
> both do not work.
> Any Ideas how to fix those two issues?
>
> Thanks,
>
> -Hackstein
>
>
> > Message: 4
> > Date: 2013年4月25日 19:44:23 -0400
> > From: Ryan Nelson <rne...@gm...>
> > Subject: Re: [Matplotlib-users] Individual custom markers and colorbar
> > To: mat...@li...
> > Message-ID: <517...@gm...>
> > Content-Type: text/plain; charset="iso-8859-1"
> >
> > Hackstein,
> >
> > Unfortunately, I'm not sure of an 'elegant' way to do what your asking
> > with a single call to scatter. Others may know a better way. However,
> > you can use rectangle patches and patch collections. (Requires a bit
> > more code than scatter but is ultimately more flexible.)
> >
> > I think the example below does what you need, but with random numbers.
> >
> > Hope it helps a little.
> >
> > Ryan
> >
> > #######################
> > import numpy as np
> > import matplotlib.pyplot as plt
> > from matplotlib.patches import Rectangle
> > from matplotlib.collections import PatchCollection
> >
> > n = 100
> >
> > # Get your xy data points, which are the centers of the rectangles.
> > xy = np.random.rand(n,2)
> >
> > # Set a fixed height
> > height = 0.02
> > # The variable widths of the rectangles
> > widths = np.random.rand(n)*0.1
> >
> > # Get a color map and color values (normalized between 0 and 1)
> > cmap = plt.cm.jet
> > colors = np.random.rand(n)
> >
> > rects = []
> > for p, w, c in zip(xy, widths, colors):
> > xpos = p[0] - w/2 # The x position will be half the width from the
> > center
> > ypos = p[1] - height/2 # same for the y position, but with height
> > rect = Rectangle( (xpos, ypos), w, height ) # Create a rectangle
> > rects.append(rect) # Add the rectangle patch to our list
> >
> > # Create a collection from the rectangles
> > col = PatchCollection(rects)
> > # set the alpha for all rectangles
> > col.set_alpha(0.3)
> > # Set the colors using the colormap
> > col.set_facecolor( cmap(colors) )
> >
> > # Make a figure and add the collection to the axis.
> > ax = plt.subplot(111)
> > ax.add_collection(col)
> > plt.show()
> >
> > ###############################
> >
> >
> > On 4/24/2013 5:35 PM, Hackstein wrote:
> >>
> >> Hi all,
> >>
> >> I am trying to get a scatter plot using a colormap. Additionally, I
> >> need to define every marker for every data point individually -- each
> >> being a rectangle with fixed height but varying width as a function of
> >> the y-value. X and y being the data coordinates, z being a number to
> >> be color coded with the colormap.
> >>
> >> Ideally, I would like to create a list of width and height values for
> >> each data point and tell the scatter plot to use those.
> >>
> >> So far I got colormapped data with custom markers (simplified):
> >>
> >> [code]
> >>
> >> import numpy as np
> >>
> >> import matplotlib.pyplot as plt
> >>
> >> from pylab import *
> >>
> >> x = y = [1,2,3,4,5]
> >>
> >> z = [2,4,6,8,10]
> >>
> >> colors = cm.gnuplot2
> >>
> >> verts_vec = list(zip([-10.,10.,10.,-10.],[-5.,-5.,5.,5.]))
> >>
> >> fig = plt.figure(1, figsize=(14.40, 9.00))
> >>
> >> ax = fig.add_subplot(1,1,1)
> >>
> >> sc = ax.scatter(x, y, c=np.asarray(z), marker=None, edgecolor='None',
> >> verts=verts_vec, cmap=colors, alpha=1.)
> >>
> >> plt.colorbar(sc, orientation='horizontal')
> >>
> >> plt.savefig('test.png', dpi=200)
> >>
> >> plt.close(1)
> >>
> >> [/code]
> >>
> >> But I need to define a marker size for each point, and I also need to
> >> do that in axis scale values, not in points.
> >>
> >> I imagine giving verts a list of N*2 tuples instead of 2 tuples, N
> >> being len(x), to define N individual markers.
> >>
> >> But when doing that I get the error that vertices.ndim==2.
> >>
> >> A less elegant way would be to plot every data point in an individual
> >> scatter plot function, using a for-loop iterating over all data
> >> points. Then, however, I see no way to apply a colormap and colorbar.
> >>
> >> What is the best way to accomplish that then?
> >>
> >> Thanks,
> >>
> >> -Hackstein
> >>
> >>
> >>
> >>
------------------------------------------------------------------------------
> >> Try New Relic Now & We'll Send You this Cool Shirt
> >> New Relic is the only SaaS-based application performance monitoring
service
> >> that delivers powerful full stack analytics. Optimize and monitor your
> >> browser, app, & servers with just a few lines of code. Try New Relic
> >> and get this awesome Nerd Life shirt!
http://p.sf.net/sfu/newrelic_d2d_apr
> >>
> >>
> >> _______________________________________________
> >> Matplotlib-users mailing list
> >> Mat...@li...
> >> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
> >
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> >
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> >
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------------------------------------------------------------------------------
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service
> > that delivers powerful full stack analytics. Optimize and monitor your
> > browser, app, & servers with just a few lines of code. Try New Relic
> > and get this awesome Nerd Life shirt!
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> > ************************************************
>
>
------------------------------------------------------------------------------
> Try New Relic Now & We'll Send You this Cool Shirt
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service
> that delivers powerful full stack analytics. Optimize and monitor your
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Hi all-
I've been working on a plot that puts the bottom and right spines at zero
(adapting some code from the example at
http://matplotlib.org/examples/pylab_examples/spine_placement_demo.html) ,
and I've discovered that setting the position of the right spine to 'zero'
seems to locate it at x=1.
Is this a bug? Or is there something that I'm missing?
Thanks,
--Chad
P.S. Sorry if this is duplicated... it seems that my messages aren't
getting though to the list.
Here's an example that demonstrates the behavior:
import matplotlib.pyplot as plt
f=plt.figure(1)
ax=plt.subplot(111)
ax.spines['left'].set_color('none')
ax.spines['top'].set_color('none')
ax.spines['right'].set_position('zero')
ax.spines['bottom'].set_position('zero')
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('right')
ax.set_xlim([-2,2])
ax.set_ylim([-2,2])
plt.show()

Thanks, Ryan, this is (amost) exactly what I was looking for. Now, I get the markers and their colors right, but I still have two problems:
The markers have a black edges, that I cannot get rid of. I've tried
rect = Rectangle(..., ec=None)
and also
col.set=edgecolor(None)
and 'None', respectively, both with no effect whatsoever.
The second problem is, that I cannot get the colorbar to work.
I tried
sc = ax.add_collection(col)
plt.colorbar(sc)
and
plt.colobar(col)
both do not work.
Any Ideas how to fix those two issues?
Thanks,
-Hackstein
> Message: 4
> Date: 2013年4月25日 19:44:23 -0400
> From: Ryan Nelson <rne...@gm...>
> Subject: Re: [Matplotlib-users] Individual custom markers and colorbar
> To: mat...@li...
> Message-ID: <517...@gm...>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> Hackstein,
> 
> Unfortunately, I'm not sure of an 'elegant' way to do what your asking 
> with a single call to scatter. Others may know a better way. However, 
> you can use rectangle patches and patch collections. (Requires a bit 
> more code than scatter but is ultimately more flexible.)
> 
> I think the example below does what you need, but with random numbers.
> 
> Hope it helps a little.
> 
> Ryan
> 
> #######################
> import numpy as np
> import matplotlib.pyplot as plt
> from matplotlib.patches import Rectangle
> from matplotlib.collections import PatchCollection
> 
> n = 100
> 
> # Get your xy data points, which are the centers of the rectangles.
> xy = np.random.rand(n,2)
> 
> # Set a fixed height
> height = 0.02
> # The variable widths of the rectangles
> widths = np.random.rand(n)*0.1
> 
> # Get a color map and color values (normalized between 0 and 1)
> cmap = plt.cm.jet
> colors = np.random.rand(n)
> 
> rects = []
> for p, w, c in zip(xy, widths, colors):
> xpos = p[0] - w/2 # The x position will be half the width from the 
> center
> ypos = p[1] - height/2 # same for the y position, but with height
> rect = Rectangle( (xpos, ypos), w, height ) # Create a rectangle
> rects.append(rect) # Add the rectangle patch to our list
> 
> # Create a collection from the rectangles
> col = PatchCollection(rects)
> # set the alpha for all rectangles
> col.set_alpha(0.3)
> # Set the colors using the colormap
> col.set_facecolor( cmap(colors) )
> 
> # Make a figure and add the collection to the axis.
> ax = plt.subplot(111)
> ax.add_collection(col)
> plt.show()
> 
> ###############################
> 
> 
> On 4/24/2013 5:35 PM, Hackstein wrote:
>> 
>> Hi all,
>> 
>> I am trying to get a scatter plot using a colormap. Additionally, I 
>> need to define every marker for every data point individually -- each 
>> being a rectangle with fixed height but varying width as a function of 
>> the y-value. X and y being the data coordinates, z being a number to 
>> be color coded with the colormap.
>> 
>> Ideally, I would like to create a list of width and height values for 
>> each data point and tell the scatter plot to use those.
>> 
>> So far I got colormapped data with custom markers (simplified):
>> 
>> [code]
>> 
>> import numpy as np
>> 
>> import matplotlib.pyplot as plt
>> 
>> from pylab import *
>> 
>> x = y = [1,2,3,4,5]
>> 
>> z = [2,4,6,8,10]
>> 
>> colors = cm.gnuplot2
>> 
>> verts_vec = list(zip([-10.,10.,10.,-10.],[-5.,-5.,5.,5.]))
>> 
>> fig = plt.figure(1, figsize=(14.40, 9.00))
>> 
>> ax = fig.add_subplot(1,1,1)
>> 
>> sc = ax.scatter(x, y, c=np.asarray(z), marker=None, edgecolor='None', 
>> verts=verts_vec, cmap=colors, alpha=1.)
>> 
>> plt.colorbar(sc, orientation='horizontal')
>> 
>> plt.savefig('test.png', dpi=200)
>> 
>> plt.close(1)
>> 
>> [/code]
>> 
>> But I need to define a marker size for each point, and I also need to 
>> do that in axis scale values, not in points.
>> 
>> I imagine giving verts a list of N*2 tuples instead of 2 tuples, N 
>> being len(x), to define N individual markers.
>> 
>> But when doing that I get the error that vertices.ndim==2.
>> 
>> A less elegant way would be to plot every data point in an individual 
>> scatter plot function, using a for-loop iterating over all data 
>> points. Then, however, I see no way to apply a colormap and colorbar.
>> 
>> What is the best way to accomplish that then?
>> 
>> Thanks,
>> 
>> -Hackstein
>> 
>> 
>> 
>> ------------------------------------------------------------------------------
>> Try New Relic Now & We'll Send You this Cool Shirt
>> New Relic is the only SaaS-based application performance monitoring service
>> that delivers powerful full stack analytics. Optimize and monitor your
>> browser, app, & servers with just a few lines of code. Try New Relic
>> and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_apr
>> 
>> 
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> ------------------------------
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Hi Michael,
Great. Now it works fine for me.
Nils
On 4/25/13, Michael Droettboom <md...@st...> wrote:
> I believe this PR fixes this bug:
>
> https://github.com/matplotlib/matplotlib/pull/1884
>
> I had been waiting for the original poster to confirm before merging,
> but I think I'll go ahead and do this anyway at this point.
>
> Mike
>
> On 04/23/2013 02:57 PM, Nils Wagner wrote:
>> Hi all,
>>
>> I cannot install matplotlib. Please find enclosed the logfile of
>> python setup.py install --prefix=$HOME/local >& log.txt
>>
>> Any idea how to resolve the problem is appreciated.
>>
>> Thanks in advance.
>> Nils
>>
>>
>>
>> ------------------------------------------------------------------------------
>> Try New Relic Now & We'll Send You this Cool Shirt
>> New Relic is the only SaaS-based application performance monitoring
>> service
>> that delivers powerful full stack analytics. Optimize and monitor your
>> browser, app, & servers with just a few lines of code. Try New Relic
>> and get this awesome Nerd Life shirt!
>> http://p.sf.net/sfu/newrelic_d2d_apr
>>
>>
>> _______________________________________________
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>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>

Dear all,
I have a set of wave directions in lon lat, but I want to display them 
in a UTM type projection. I believe the directions will be distorted, 
but I'm not sure by how much.
Does anyone know of a method for calculating new directions under a 
projection change?
Thanks again for your help,
Mat
-- 
Dr. Mathew Topper
Institute for Energy Systems
School of Engineering
The University of Edinburgh
Faraday Building
The King’s Buildings
Edinburgh EH9 3JL
Tel: +44 (0)131 650 5570
School fax: +44 (0)131 650 6554
mat...@ed... <mailto:mat...@ed...>
http://www.see.ed.ac.uk <http://www.see.ed.ac.uk/>
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

Hi,
Anyone can provide some info on what "agg.buffer_rgba" returns and maybe 
even some suggestion on how to resolve this issue in the wxagg backend.
Thanks
Werner
P.S.
The archive on Sourceforge for this list stops in June 2012, noticed 
this as I wanted to check if there are answers I didn't get for some reason.
http://sourceforge.net/mailarchive/forum.php?forum_name=matplotlib-users
On 20/04/2013 08:58, Werner F. Bruhin wrote:
> Hi,
>
> I am trying to get matplotlib 1.2.0 to work with wxPython Phoenix - will
> provide a patch when it is working.
>
> Made the changes to backend_wx* for things like EmptyImage/EmptyBitmap
> and Toolbar but I am stuck on the following.
>
> if bbox is None:
> # agg => rgba buffer -> bitmap
> if 'phoenix' in wx.PlatformInfo:
> return wx.Bitmap.FromBufferRGBA(int(agg.width),
> int(agg.height),
> memoryview(agg.buffer_rgba()))
> else:
> return wx.BitmapFromBufferRGBA(int(agg.width), int(agg.height),
> agg.buffer_rgba())
> else:
> # agg => rgba buffer -> bitmap => clipped bitmap
> return _WX28_clipped_agg_as_bitmap(agg, bbox)
>
> TypeError: cannot make memory view because object does not have the
> buffer interface
> File "h:\devProjectsT\aaTests\matplotlib\wxembedding-5.py", line 63, in
> <module>
> demo()
> File "h:\devProjectsT\aaTests\matplotlib\wxembedding-5.py", line 60, in demo
> app.MainLoop()
> File "c:\Python27\Lib\site-packages\wx-2.9.6-msw-phoenix\wx\core.py",
> line 1841, in MainLoop
> rv = wx.PyApp.MainLoop(self)
> File "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wx.py",
> line 1209, in _onPaint
> self.draw(drawDC=drawDC)
> File
> "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wxagg.py",
> line 61, in draw
> self.bitmap = _convert_agg_to_wx_bitmap(self.get_renderer(), None)
> File
> "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wxagg.py",
> line 173, in _convert_agg_to_wx_bitmap
> memoryview(agg.buffer_rgba()))
>
> I tried using "memoryview" based on a suggestion by Robin Dunn, and
> based on the following info I see in the debugger that should work no?
>
> agg.buffer_rgba()
> <read-write buffer ptr 0x05400638, size 229200 at 0x055FC680>
> type(agg.buffer_rgba())
> <type 'buffer'>
> agg
> <matplotlib.backends.backend_agg.RendererAgg instance at 0x04BA0670>
>
> If I don't use "memoryview" (which would probably be preferred) I get
> the following exception.
>
> Can someone help us figure this one out.
>
> Thanks
> Werner
>
>
> TypeError: Bitmap.FromBufferRGBA(): argument 3 has unexpected type 'buffer'
> File "h:\devProjectsT\aaTests\matplotlib\wxembedding-5.py", line 63, in
> <module>
> demo()
> File "h:\devProjectsT\aaTests\matplotlib\wxembedding-5.py", line 60, in demo
> app.MainLoop()
> File "c:\Python27\Lib\site-packages\wx-2.9.6-msw-phoenix\wx\core.py",
> line 1841, in MainLoop
> rv = wx.PyApp.MainLoop(self)
> File "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wx.py",
> line 1209, in _onPaint
> self.draw(drawDC=drawDC)
> File
> "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wxagg.py",
> line 61, in draw
> self.bitmap = _convert_agg_to_wx_bitmap(self.get_renderer(), None)
> File
> "c:\Python27\Lib\site-packages\matplotlib\backends\backend_wxagg.py",
> line 173, in _convert_agg_to_wx_bitmap
> agg.buffer_rgba())
>
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