matplotlib-users Mailing List for matplotlib (Page 3)

Hi 
I have a code to plot a histogram and I am trying to add a best fit line
following this example
http://matplotlib.sourceforge.net/examples/pylab_examples/histogram_demo.html
but run into this error
Traceback (most recent call last):
 File "/home/Astro/count_Histogram.py", line 54, in <module>
 l = plt.plot(bins, y, 'r--', linewidth=1)
 File "/usr/lib/pymodules/python2.7/matplotlib/pyplot.py", line 2467, in
plot
 ret = ax.plot(*args, **kwargs)
 File "/usr/lib/pymodules/python2.7/matplotlib/axes.py", line 3893, in plot
 for line in self._get_lines(*args, **kwargs):
 File "/usr/lib/pymodules/python2.7/matplotlib/axes.py", line 322, in
_grab_next_args
 for seg in self._plot_args(remaining, kwargs):
 File "/usr/lib/pymodules/python2.7/matplotlib/axes.py", line 300, in
_plot_args
 x, y = self._xy_from_xy(x, y)
 File "/usr/lib/pymodules/python2.7/matplotlib/axes.py", line 240, in
_xy_from_xy
 raise ValueError("x and y must have same first dimension")
ValueError: x and y must have same first dimension
My Code 
import matplotlib.pyplot as plt
import math
import numpy as np
import mpl_toolkits.mplot3d.axes3d
import matplotlib.mlab as mlab
counts = []
F = '/home/Astro/outfiles/outmag21_5dr_38_68.txt'
f = open(F)
for line in f:
 if line != ' ': 
 columns = line.split() 
 count = columns[3] 
 count = int(count)
 counts.append(count)
 C = np.array(counts, dtype=float)
 
avg = sum(C)/len(C)
diff = C-avg
sigma = np.sqrt((1./len(C))*(diff**2))
bins = 20
plt.hist(C, bins, range=None, normed=False, weights=None, cumulative=False,
bottom=None, histtype='bar', align='mid', orientation='vertical',
rwidth=None, log = False, color=None, label=None)
plt.title("")
plt.text(25,20,'M < -21.5' '\n' 'N Halos 3877' '\n' 'Length Cell 38.68Mpc'
'\n' 'N Cells 269' '\n' 'Avg Halo per Cell 14.35 ')
plt.xlabel("Halos/Cell")
plt.ylabel("Number Cells with N Halos")
y = mlab.normpdf( bins, avg, sigma)
print(len(y))
l = plt.plot(bins, y, 'r--', linewidth=1)
plt.show()
My first question is do x and y refer to the values in l = plt.plot(bins,
y, 'r--', linewidth=1) which for my case are bins and y?
if that is the case how can I get then to be the same first dimension?
-- 
View this message in context: http://old.nabble.com/ValueError%3A-x-and-y-must-have-same-first-dimension-tp34218704p34218704.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

On Thursday, July 26, 2012, Joshua Koehler wrote:
> Hi all,
>
> I am getting the following error message:
>
> 'Figure' object has no attribute 'show'
>
> When running matplotlib in Ubuntu 12.04, with matplotlib 1.2.x and pylab
> 1.6.2.
>
> The code is set up as such:
>
> fig = pylab.figure()
> ...
> fig.show()
>
> This works fine on Mac OSX 10.6 with matplotlib 1.1.0 and pylab 1.6.1
>
> Any thoughts or similar experiences?
>
> Thanks!
>
> Josh
I doubt that ever should have worked. If it did, then something was
seriously messed up. Also, note there isnt really a package called
"pylab". There is a special sub-module in matplotlib called pylab, that
you typically do "from pylab import *" with. The version number you are
giving more likely corresponds to the numpy version number.
The show() function is a part of the pyplot and pylab namespaces.
Ben Root

Hi all,
I am getting the following error message:
'Figure' object has no attribute 'show'
When running matplotlib in Ubuntu 12.04, with matplotlib 1.2.x and pylab 1.6.2. 
The code is set up as such:
fig = pylab.figure()
...
fig.show()
This works fine on Mac OSX 10.6 with matplotlib 1.1.0 and pylab 1.6.1
Any thoughts or similar experiences?
Thanks!
Josh

Hi,
you should be also able to create the axes as:
ax = plt.figure( figsize=(x,y) ).add_subplot(111)
with figsize big enough to fit just the legend
Cheers
Francesco
2012年7月26日 Damon McDougall <dam...@gm...>:
> On Thu, Jul 26, 2012 at 06:05:39PM +0200, Andreas Hilboll wrote:
>> > Hi Andreas,
>> >
>> > 2012年7月26日 Andreas Hilboll <li...@hi...>:
>> >> Hi,
>> >>
>> >> I would like to create a figure which only contains a legend, and no
>> >> axes
>> >> at all. I would like to manually assign the colors. I found this here:
>> >>
>> >> http://stackoverflow.com/a/3302666
>> >>
>> >> but from there on, I'd like to remove the axes, and put the legend into
>> >> three columns.
>> >
>> > If the plot attached it's fine for you it's easy:
>> >
>> > import matplotlib.pyplot as plt
>> > ax = plt.subplot() #create the axes
>> > ax.set_axis_off() #turn off the axis
>> > .... #do patches and labels
>> > ax.legend(patches, labels, ...) #legend alone in the figure
>> > plt.show()
>> >
>> > Cheers,
>> > Francesco
>>
>> That's really easy :) I could live with this solution, applying some
>> external tool like pdfcrop to the result. Of course, it would be nicer if
>> the PDF's page size would be exactly that of the legend (plus some
>> margin), so that I wouldn't have to resort to external tools ...
>>
>> Any ideas?
>>
>
> How about
>
> plt.savefig('roflcakes.png', bbox_inches='tight', pad_inches=0.1)
>
> Since the other artists are invisible, that should crop to just your
> legend. I'm assuming matplotlib updates the BoundingBox such that it
> doesn't include invisible artists.
>
>>
>> Cheers, A.
>>
>>
>> ------------------------------------------------------------------------------
>> Live Security Virtual Conference
>> Exclusive live event will cover all the ways today's security and
>> threat landscape has changed and how IT managers can respond. Discussions
>> will include endpoint security, mobile security and the latest in malware
>> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
> --
> Damon McDougall
> http://damon-is-a-geek.com
> B2.39
> Mathematics Institute
> University of Warwick
> Coventry
> West Midlands
> CV4 7AL
> United Kingdom
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

On Thu, Jul 26, 2012 at 06:05:39PM +0200, Andreas Hilboll wrote:
> > Hi Andreas,
> >
> > 2012年7月26日 Andreas Hilboll <li...@hi...>:
> >> Hi,
> >>
> >> I would like to create a figure which only contains a legend, and no
> >> axes
> >> at all. I would like to manually assign the colors. I found this here:
> >>
> >> http://stackoverflow.com/a/3302666
> >>
> >> but from there on, I'd like to remove the axes, and put the legend into
> >> three columns.
> >
> > If the plot attached it's fine for you it's easy:
> >
> > import matplotlib.pyplot as plt
> > ax = plt.subplot() #create the axes
> > ax.set_axis_off() #turn off the axis
> > .... #do patches and labels
> > ax.legend(patches, labels, ...) #legend alone in the figure
> > plt.show()
> >
> > Cheers,
> > Francesco
> 
> That's really easy :) I could live with this solution, applying some
> external tool like pdfcrop to the result. Of course, it would be nicer if
> the PDF's page size would be exactly that of the legend (plus some
> margin), so that I wouldn't have to resort to external tools ...
> 
> Any ideas?
>
How about
plt.savefig('roflcakes.png', bbox_inches='tight', pad_inches=0.1)
Since the other artists are invisible, that should crop to just your
legend. I'm assuming matplotlib updates the BoundingBox such that it
doesn't include invisible artists.
> 
> Cheers, A.
> 
> 
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and 
> threat landscape has changed and how IT managers can respond. Discussions 
> will include endpoint security, mobile security and the latest in malware 
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
-- 
Damon McDougall
http://damon-is-a-geek.com
B2.39
Mathematics Institute
University of Warwick
Coventry
West Midlands
CV4 7AL
United Kingdom

On Thu, Jul 26, 2012 at 5:05 PM, Andreas Hilboll <li...@hi...> wrote:
> That's really easy :) I could live with this solution, applying some
> external tool like pdfcrop to the result.
If you can use other output, you can generate a png image, which would
be easier to cut (even inside MPL.image). This, without entering in
more complicated issues, that I don't know if they are even possible.

> Hi Andreas,
>
> 2012年7月26日 Andreas Hilboll <li...@hi...>:
>> Hi,
>>
>> I would like to create a figure which only contains a legend, and no
>> axes
>> at all. I would like to manually assign the colors. I found this here:
>>
>> http://stackoverflow.com/a/3302666
>>
>> but from there on, I'd like to remove the axes, and put the legend into
>> three columns.
>
> If the plot attached it's fine for you it's easy:
>
> import matplotlib.pyplot as plt
> ax = plt.subplot() #create the axes
> ax.set_axis_off() #turn off the axis
> .... #do patches and labels
> ax.legend(patches, labels, ...) #legend alone in the figure
> plt.show()
>
> Cheers,
> Francesco
That's really easy :) I could live with this solution, applying some
external tool like pdfcrop to the result. Of course, it would be nicer if
the PDF's page size would be exactly that of the legend (plus some
margin), so that I wouldn't have to resort to external tools ...
Any ideas?
Cheers, A.

Hi Andreas,
2012年7月26日 Andreas Hilboll <li...@hi...>:
> Hi,
>
> I would like to create a figure which only contains a legend, and no axes
> at all. I would like to manually assign the colors. I found this here:
>
> http://stackoverflow.com/a/3302666
>
> but from there on, I'd like to remove the axes, and put the legend into
> three columns.
If the plot attached it's fine for you it's easy:
import matplotlib.pyplot as plt
ax = plt.subplot() #create the axes
ax.set_axis_off() #turn off the axis
.... #do patches and labels
ax.legend(patches, labels, ...) #legend alone in the figure
plt.show()
Cheers,
Francesco
>
> Any help is greatly appreciated :)
> Andreas.
>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

Hi,
I would like to create a figure which only contains a legend, and no axes
at all. I would like to manually assign the colors. I found this here:
 http://stackoverflow.com/a/3302666
but from there on, I'd like to remove the axes, and put the legend into
three columns.
Any help is greatly appreciated :)
Andreas.

It is Python 2.5.2 (r252.60911, Jan 24 2010, 14:53:14)
[GCC 4.3.2] on linux2.
I believe the Matplotlib version there is outdated or the locale is an issue.
Thanks for the help!
________________________________
 From: Phil Elson <pel...@gm...>
To: Luciano Fleischfresser <lf...@ut...> 
Cc: ""Mat...@li..."" <Mat...@li...> 
Sent: Thursday, July 26, 2012 5:02 AM
Subject: Re: [Matplotlib-users] axvspan with dates on x-axis
 
Luciano got in touch offline and my suggestions worked for a certain
version of Python.
Luciano, were you trying it in python3? If not, what version of Python
was it that wasn't working for you?
Thanks,
On 24 July 2012 18:26, Luciano Fleischfresser <l_...@ya...> wrote:
> Still not working. The output looks like this:
>
> File "NotasFaltasdoisgraficos.py", line 58
>  ax3.axvspan(*mdates.datestr2num(['05/18/2012', '06/30/2012']),
> facecolor='g', alpha=0.5)
>
> ^
> SyntaxError: invalid syntax
>
> When you say "...change the months to short English form" you mean in the
> data file?
> That is, Abr -> Apr, Mai -> May??? ...still did not work.
>
> ________________________________
> From: Phil Elson <pel...@gm...>
> To: Luciano Fleischfresser <lf...@ut...>
> Cc: "Mat...@li..."
> <Mat...@li...>
> Sent: Monday, July 23, 2012 5:45 PM
> Subject: Re: [Matplotlib-users] axvspan with dates on x-axis
>
> Looks like your very close.
>
>
> I needed to change the months to short English form, change the line
>
> ax3.grid('True') to ax3.grid(True)
>
> and add the line
>
> ax3.axvspan(*mdates.datestr2num(['05/18/2012', '06/30/2012']),
> facecolor='g', alpha=0.5)
>
> To get the box on the lower plot.
>
> Hope that helps,
>
>
>
> On 23 July 2012 20:42, Luciano Fleischfresser <l_...@ya...> wrote:
>> I want to place a colored vertical range on my plot and came across the
>> following example:
>>
>>
>> http://stackoverflow.com/questions/8270981/in-a-matplotlib-plot-can-i-highlight-specific-x-value-ranges/8271438#8271438
>>
>> It shows what I am trying to do using axvspan.
>> However, I was not able to reproduce the second plot with dates.
>> Errors like 'invalid syntax' for color='red' and others prevented me from
>> reproducing the plot.
>> The demo from Matplotlib gallery worked fine for me. My plot also has
>> dates
>> on the x-axis.
>>
>> I am attaching code and data file. Hope someone can point me in the right
>> direction.
>>
>> L Fleischfresser
>>
>>
>> ------------------------------------------------------------------------------
>> Live Security Virtual Conference
>> Exclusive live event will cover all the ways today's security and
>> threat landscape has changed and how IT managers can respond. Discussions
>> will include endpoint security, mobile security and the latest in malware
>> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>

Luciano got in touch offline and my suggestions worked for a certain
version of Python.
Luciano, were you trying it in python3? If not, what version of Python
was it that wasn't working for you?
Thanks,
On 24 July 2012 18:26, Luciano Fleischfresser <l_...@ya...> wrote:
> Still not working. The output looks like this:
>
> File "NotasFaltasdoisgraficos.py", line 58
> ax3.axvspan(*mdates.datestr2num(['05/18/2012', '06/30/2012']),
> facecolor='g', alpha=0.5)
>
> ^
> SyntaxError: invalid syntax
>
> When you say "...change the months to short English form" you mean in the
> data file?
> That is, Abr -> Apr, Mai -> May??? ...still did not work.
>
> ________________________________
> From: Phil Elson <pel...@gm...>
> To: Luciano Fleischfresser <lf...@ut...>
> Cc: "Mat...@li..."
> <Mat...@li...>
> Sent: Monday, July 23, 2012 5:45 PM
> Subject: Re: [Matplotlib-users] axvspan with dates on x-axis
>
> Looks like your very close.
>
>
> I needed to change the months to short English form, change the line
>
> ax3.grid('True') to ax3.grid(True)
>
> and add the line
>
> ax3.axvspan(*mdates.datestr2num(['05/18/2012', '06/30/2012']),
> facecolor='g', alpha=0.5)
>
> To get the box on the lower plot.
>
> Hope that helps,
>
>
>
> On 23 July 2012 20:42, Luciano Fleischfresser <l_...@ya...> wrote:
>> I want to place a colored vertical range on my plot and came across the
>> following example:
>>
>>
>> http://stackoverflow.com/questions/8270981/in-a-matplotlib-plot-can-i-highlight-specific-x-value-ranges/8271438#8271438
>>
>> It shows what I am trying to do using axvspan.
>> However, I was not able to reproduce the second plot with dates.
>> Errors like 'invalid syntax' for color='red' and others prevented me from
>> reproducing the plot.
>> The demo from Matplotlib gallery worked fine for me. My plot also has
>> dates
>> on the x-axis.
>>
>> I am attaching code and data file. Hope someone can point me in the right
>> direction.
>>
>> L Fleischfresser
>>
>>
>> ------------------------------------------------------------------------------
>> Live Security Virtual Conference
>> Exclusive live event will cover all the ways today's security and
>> threat landscape has changed and how IT managers can respond. Discussions
>> will include endpoint security, mobile security and the latest in malware
>> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>

Great tip, alot simpler than i expected. Although you still need to specify
the correct dimensions of the axes, otherwise it wil be interpolated after
all. If in my example i increase the figsize by a factor of 2, the image
stretches along with it.
Thanks!
Rutger
On 25 July 2012 19:11, Benjamin Root <ben...@ou...> wrote:
>
> If you are using v1.1.0 or later, you can set interpolation to "none".
> Note the difference between providing the string "none", which means to do
> no interpolation at all, while the python None means to do the default.
>
> Ben Root
>

On 2012年07月25日 12:45 PM, Scott Henderson wrote:
> Thanks for the response. To be more specific, if I run the modified
> script in an ipython --pylab terminal:
>
> In [1]: %run lasso_demo.py
>
> In [2]:
>
> The function returns, and the lasso manager is garbage collected as
> you say. In other words, the plot shows up, but I can't draw a lasso
> and select points. If I run the script in ipython without the pylab
> flag it works!
>
> Why does enabling --pylab have this effect? Since I use pylab for
> day-to-day computing I'd like to incorporate some of these widgit
> tools in interactive sessions, but maybe that's not possible?
It is entirely possible.
--pylab mode turns mpl interactive mode on, so that the call to show() 
does not block. But because you have that call inside your function, if 
show() doesn't block, you immediately return from the function, and as 
Tony noted, your widget gets garbage-collected.
Try this: keep references to your figure and LassoManager in a list, 
dictionary, class, or whatever you like, and return that from your run() 
function. When you call run, assign its output to a name, so there is a 
reference to it, and indirectly to the LassoManager.
Eric
>
> Thanks,
> Scott
>
>
>
> On Jul 25, 2012, at 5:10 PM, Tony Yu wrote:
>
>> def run(points):
>> data = [Datum(*xy) for xy in points]
>> fig = figure()
>> ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1), autoscale_on=False)
>> lman = LassoManager(ax, data)
>> show()
>>
>> if __name__ == '__main__':
>> points = rand(100, 2)
>> run(points)
>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

Thanks for the response. To be more specific, if I run the modified script in an ipython --pylab terminal:
In [1]: %run lasso_demo.py
In [2]:
The function returns, and the lasso manager is garbage collected as you say. In other words, the plot shows up, but I can't draw a lasso and select points. If I run the script in ipython without the pylab flag it works!
Why does enabling --pylab have this effect? Since I use pylab for day-to-day computing I'd like to incorporate some of these widgit tools in interactive sessions, but maybe that's not possible? 
Thanks, 
Scott
On Jul 25, 2012, at 5:10 PM, Tony Yu wrote:
> def run(points):
> data = [Datum(*xy) for xy in points]
> fig = figure()
> ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1), autoscale_on=False)
> lman = LassoManager(ax, data)
> show()
> 
> if __name__ == '__main__':
> points = rand(100, 2)
> run(points)

On Wed, Jul 25, 2012 at 5:11 PM, Scott Henderson <st...@co...> wrote:
> Hello, I'm trying to incorporate some matplotlib widgets into my scripts
> that generate plots. I'm unsure why, but if I wrap the figure creation
> lines in lasso_demo.py with a function the demo does not work. Why?
>
> #Original:
> #------------
> if __name__ == '__main__':
> data = [Datum(*xy) for xy in randn(100,2)]
> fig = figure()
> ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1), autoscale_on=False)
> lman = LassoManager(ax, data)
> show()
>
> #Change:
> #------------
> def run(points):
> data = [Datum(*xy) for xy in points]
> fig = figure()
> ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1), autoscale_on=False)
> lman = LassoManager(ax, data)
> show()
>
> if __name__ == '__main__':
> points = rand(100, 2)
> run(points)
>
>
> --
> ---------------
> Scott T. Henderson
> http://www.geo.cornell.edu/eas/gstudent/sth54/contact.html
>
Your changes work fine on my system.
Are you sure the example you wrote above is exactly the same as what you're
running? For example, if I move the `show` out of the function and back
into '__main__', then the lasso stops working (because the lasso manager
gets garbage collected). Otherwise, I can't reproduce the issue. Actually,
what did you mean by "does not work" (e.g., no lasso, error,)?
-Tony

Hello, I'm trying to incorporate some matplotlib widgets into my scripts 
that generate plots. I'm unsure why, but if I wrap the figure creation 
lines in lasso_demo.py with a function the demo does not work. Why?
#Original:
#------------
if __name__ == '__main__':
 data = [Datum(*xy) for xy in randn(100,2)]
 fig = figure()
 ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1), autoscale_on=False)
 lman = LassoManager(ax, data)
 show()
#Change:
#------------
def run(points):
 data = [Datum(*xy) for xy in points]
 fig = figure()
 ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1), autoscale_on=False)
 lman = LassoManager(ax, data)
 show()
if __name__ == '__main__':
 points = rand(100, 2)
 run(points)
-- 
---------------
Scott T. Henderson
http://www.geo.cornell.edu/eas/gstudent/sth54/contact.html

On Wednesday, July 25, 2012, Rutger Kassies wrote:
> Dear list,
>
> I am trying to plot an image using imshow for which i want to have full
> control of the interpolation taking place. I would rather not have any
> interpolation at all, but if the input image is very small, it may be
> interpolated (nearest neighbor) with an integer factor of my choice (2x,3x
> etc.).
>
> To achieve this i decided that the first and most simple case would be to
> output exactly the image which i load by using plt.imread(). If this
> succeeds i would expand it by adding a buffer around the image to allow
> some annotation like for example a title and a colorbar.
>
> Here is my initial try:
>
> import matplotlib.pyplot as plt
>
> img = plt.imread('D:\\input_image.png')
>
> # get x and y dimension of the image
> xpixels = img.shape[1]
> ypixels = img.shape[0]
>
> # calculate the dimensions in inch for a given dpi
> zoomfactor = 1
> dpi = 72
> xinch = ( xpixels * zoomfactor) / dpi
> yinch = (ypixels * zoomfactor) / dpi
>
> # create the figure
> fig = plt.figure(figsize=(xinch,yinch))
>
> # stretch the axes to the full extent of the figure
> ax = plt.axes([0.0, 0.0, 1.0, 1.0])
>
> ax.imshow(img, interpolation='nearest')
>
> # hide axis stuff
> ax.axes.get_yaxis().set_visible(False)
> ax.axes.get_xaxis().set_visible(False)
>
> # remove the border of the axes
> plt.setp(ax, frame_on=False)
>
> # save the figure with the given dpi
> plt.savefig('D:\\output_image.png', dpi=dpi)
>
>
> The resulting output image is equal in dimensions to the input image, so
> far so good. However, when i overlay them in a graphics program, i can
> clearly see that some nearest neighbor interpolation has taken place. It
> appears as if the top-right corner of the image is plotted 1 or 2 pixels
> beyond the edge of the figure. Does anyone have any idea how to get this
> right?
>
> Thanks in advance!
>
>
> Regards,
> Rutger
>
>
If you are using v1.1.0 or later, you can set interpolation to "none". Note
the difference between providing the string "none", which means to do no
interpolation at all, while the python None means to do the default.
Ben Root

Dear list,
I am trying to plot an image using imshow for which i want to have full
control of the interpolation taking place. I would rather not have any
interpolation at all, but if the input image is very small, it may be
interpolated (nearest neighbor) with an integer factor of my choice (2x,3x
etc.).
To achieve this i decided that the first and most simple case would be to
output exactly the image which i load by using plt.imread(). If this
succeeds i would expand it by adding a buffer around the image to allow
some annotation like for example a title and a colorbar.
Here is my initial try:
import matplotlib.pyplot as plt
img = plt.imread('D:\\input_image.png')
# get x and y dimension of the image
xpixels = img.shape[1]
ypixels = img.shape[0]
# calculate the dimensions in inch for a given dpi
zoomfactor = 1
dpi = 72
xinch = ( xpixels * zoomfactor) / dpi
yinch = (ypixels * zoomfactor) / dpi
# create the figure
fig = plt.figure(figsize=(xinch,yinch))
# stretch the axes to the full extent of the figure
ax = plt.axes([0.0, 0.0, 1.0, 1.0])
ax.imshow(img, interpolation='nearest')
# hide axis stuff
ax.axes.get_yaxis().set_visible(False)
ax.axes.get_xaxis().set_visible(False)
# remove the border of the axes
plt.setp(ax, frame_on=False)
# save the figure with the given dpi
plt.savefig('D:\\output_image.png', dpi=dpi)
The resulting output image is equal in dimensions to the input image, so
far so good. However, when i overlay them in a graphics program, i can
clearly see that some nearest neighbor interpolation has taken place. It
appears as if the top-right corner of the image is plotted 1 or 2 pixels
beyond the edge of the figure. Does anyone have any idea how to get this
right?
Thanks in advance!
Regards,
Rutger

On 7/24/12 8:04 PM, Vladan Divljak wrote:
> Hi,
>
> I'm a physics student, and got interested in retrieving meteorological 
> data (through Internet)
> I spent good couple of days to just make a picture of file formats 
> providing this data, sources and tools for reading it, and then give 
> up discouridged by ECMWF and finally EUMETSAT portals. I have a 
> picture of total mess unlike my expectations, like why I "must" 
> strictly study Fortran when data is so divergent?
>
> Then I thought to make it easier by using some of available java 
> frontends which were offered on sites I already visited. First I tried 
> three different versions of OPeNDAP Data Connector, but it couldn't 
> run on my Windows PC. Then I found IDV from Unidata, and after 
> spending some time with it I think it has very good scheme for 
> application workflow, while it has a learning curve and it's most 
> useful for US residents, while I live somewhere in Europe.
>
> I discovered also Basemap, and it's excellent package. If data is 
> provided, it offers interface and utilities to whole Python in the 
> same way. That is why I joined this mailing list and thought to ask 
> for similar experiences, potentially advice on available tools for 
> retrieving meteorological data and data itself.
> For example, I can retrieve data from GFS/NOAA (which is BTW great, as 
> only light in whole this experiance), and would appreciate similar 
> maybe localized meso model data, and current satellite or radar data, 
> or appropriate tools. I'm thinking I must have missed something, as 
> this shouldn't be so difficult task, or?
Vladan: You can access current NOAA forecasts (atmosphere and ocean) 
via opendap from http://nomads.ncep.noaa.gov. The netcdf4-python 
package (http://netcdf4-python.googlecode.com) can connect to these 
remote datasets via opendap, in fact many of the Basemap examples use 
this (see fcstmaps.py and plotsst.py in the examples directory).
You might also be interested in the data here
http://motherlode.ucar.edu/thredds/catalog.html
and here
http://www.esrl.noaa.gov/psd/data/gridded/
-Jeff

On Tuesday, July 24, 2012, Vladan Divljak wrote:
> On Wed, Jul 25, 2012 at 4:22 AM, Eric Firing wrote:
>
>>
>> It sounds like maybe you missed http://pydap.org.
>>
>
> I have it :)
> I installed it yesterday.
> On a first sight, it seemed to me like a tool for users interested in
> making local dap server (I have even considered that, until I run to IDV),
> but maybe I didn't got it's potential.
>
> I'll check it out again, thanks
>
For archived data, NCDC is king in my book. Especially when it comes to US
NEXRAD radar data. They offer both GUI and CLI tools for data
visualization and conversion. Usually, I Jude it to convert my radar data
into netcdf format.
By the way, there are three major binary data formats to know in the metro
world: grib, netcdf and hdf.
Happy data mining!
Ben Root

On Wed, Jul 25, 2012 at 4:51 AM, Jeff Whitaker <js...@fa...> wrote:
> Vladan: You can access current NOAA forecasts (atmosphere and ocean) via
> opendap from http://nomads.ncep.noaa.gov. The netcdf4-python package (
> http://netcdf4-python.**googlecode.com<http://netcdf4-python.googlecode.com>)
> can connect to these remote datasets via opendap, in fact many of the
> Basemap examples use this (see fcstmaps.py and plotsst.py in the examples
> directory).
>
> You might also be interested in the data here
>
> http://motherlode.ucar.edu/**thredds/catalog.html<http://motherlode.ucar.edu/thredds/catalog.html>
>
> and here
>
> http://www.esrl.noaa.gov/psd/**data/gridded/<http://www.esrl.noaa.gov/psd/data/gridded/>
>
>
Thanks Jeff,
and all you guys. I'm glad I asked this question, as I got great responses
in just half an hour, compared to mostly useless days searching for same
Best wishes

On Wed, Jul 25, 2012 at 4:38 AM, Patrick Marsh wrote:
> I'm finishing up my PhD in Meteorology. Although I don't use it explicitly
> use pydap for my research, I do use it to download meteorological data from
> various dap servers.
>
OK, thanks
I'm just browsing datasets at opendap wiki, which I somehow missed the
other day, probably because of lots of informations about formats, sources
...
I guess I had to ask, to get to second level. Now it seems like
straitforward: parse thredds catalogs and opendap datasets, and
additionally search for same, then dive ;)
Thanks for your pointers in right direction
Cheers :)

On Wed, Jul 25, 2012 at 4:22 AM, Eric Firing wrote:
>
> It sounds like maybe you missed http://pydap.org.
>
I have it :)
I installed it yesterday.
On a first sight, it seemed to me like a tool for users interested in
making local dap server (I have even considered that, until I run to IDV),
but maybe I didn't got it's potential.
I'll check it out again, thanks

On 2012年07月24日 4:04 PM, Vladan Divljak wrote:
> Hi,
>
> I'm a physics student, and got interested in retrieving meteorological
> data (through Internet)
> I spent good couple of days to just make a picture of file formats
> providing this data, sources and tools for reading it, and then give up
> discouridged by ECMWF and finally EUMETSAT portals. I have a picture of
> total mess unlike my expectations, like why I "must" strictly study
> Fortran when data is so divergent?
>
> Then I thought to make it easier by using some of available java
> frontends which were offered on sites I already visited. First I tried
> three different versions of OPeNDAP Data Connector, but it couldn't run
> on my Windows PC. Then I found IDV from Unidata, and after spending some
> time with it I think it has very good scheme for application workflow,
> while it has a learning curve and it's most useful for US residents,
> while I live somewhere in Europe.
>
> I discovered also Basemap, and it's excellent package. If data is
> provided, it offers interface and utilities to whole Python in the same
> way. That is why I joined this mailing list and thought to ask for
> similar experiences, potentially advice on available tools for
> retrieving meteorological data and data itself.
> For example, I can retrieve data from GFS/NOAA (which is BTW great, as
> only light in whole this experiance), and would appreciate similar maybe
> localized meso model data, and current satellite or radar data, or
> appropriate tools. I'm thinking I must have missed something, as this
> shouldn't be so difficult task, or?
>
It sounds like maybe you missed http://pydap.org.
Eric

Hi,
I'm a physics student, and got interested in retrieving meteorological data
(through Internet)
I spent good couple of days to just make a picture of file formats
providing this data, sources and tools for reading it, and then give up
discouridged by ECMWF and finally EUMETSAT portals. I have a picture of
total mess unlike my expectations, like why I "must" strictly study Fortran
when data is so divergent?
Then I thought to make it easier by using some of available java frontends
which were offered on sites I already visited. First I tried three
different versions of OPeNDAP Data Connector, but it couldn't run on my
Windows PC. Then I found IDV from Unidata, and after spending some time
with it I think it has very good scheme for application workflow, while it
has a learning curve and it's most useful for US residents, while I live
somewhere in Europe.
I discovered also Basemap, and it's excellent package. If data is provided,
it offers interface and utilities to whole Python in the same way. That is
why I joined this mailing list and thought to ask for similar experiences,
potentially advice on available tools for retrieving meteorological data
and data itself.
For example, I can retrieve data from GFS/NOAA (which is BTW great, as only
light in whole this experiance), and would appreciate similar maybe
localized meso model data, and current satellite or radar data, or
appropriate tools. I'm thinking I must have missed something, as this
shouldn't be so difficult task, or?