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Pablo Romero wrote:
> Jeff,
>
> Here's a link to the website that's creating the basemap plots with 
> the "H"'s and "L"'s:
>
> http://magicseaweed.com/msw-surf-charts2.php?chart=64&res=750&type=pressure&starttime= 
>
>
> As you can see, this website's "pressure chart" interface is based on 
> creating individual images for each point in a time series. And, if 
> you click on any one of the "region" links below the plot, you'll be 
> presented with the same pressure plot for a sub-region; obviously, 
> this needs to be based on an automated process, since I seriously 
> doubt someone is manually creating each plot for each time step for 
> each "sub-region" in their catalog...bottom line, there MUST be a 
> systematic way to add those "H" and "L" characters to closed contours 
> that are local min/max AND that are LARGE enough to hold an "H" or "L" 
> character (as you mentioned, some of the smaller closed contours dont 
> display the 'H'/'L' characters).
>
>
> So the big question is: how could one go about setting something like 
> this up???
> Do you think it would be possible to accomplish this with the 
> function/tutorial you provided???
> If so, could you please help me understand a little more how I would 
> go about using that function? (sorry, I wasnt very clear on how it 
> should be applied to this problem).
>
>
> I know for a fact that this website is using matplotlib/basemap to 
> create these plots. Theyre using a python interface to 
> matplolib/basemap named 'pygrads'; it provides basemap/mpl plotting 
> capabilities to an existing application named GrADS. I just dont know 
> how the heck they got those "H/L" characters there....
>
> Thanks again for the help,
>
> Pablo

Pablo: I've added a script (attached to this email) called 
"plothighsandlows.py" in the basemap examples directory that shows how 
to do this. It uses scipy.ndimage.filters, so you'll need to have scipy 
installed to run it.

-Jeff
>
>
>
> ----------------------------------------
>> Date: Fri, 6 Mar 2009 06:07:10 -0700
>> From: js...@fa...
>> To: rom...@ho...
>> CC: mat...@li...
>> Subject: Re: [Matplotlib-users] plotting air pressure data with 
>> contour() function
>>
>> Jeff Whitaker wrote:
>>> Pablo Romero wrote:
>>>
>>>> Hello,
>>>> I have a question about plotting pressure contours with matplotlib.
>>>>
>>>> I've seen other applications using matplotlib where the pressure 
>>>> contours are drawn with annoted text "H" and "L" characters being 
>>>> drawn in the centers of closed contours...
>>>>
>>>> i.e., if there is a closed contour line, and its value is over a 
>>>> certain threshold value, plot an "H" to indicate a "high pressure 
>>>> zone", else plot a "L" to indicate a "low pressure zone."
>>>>
>>>> This is standard weather map plotting stuff, and Ive definitely 
>>>> seen other plots produced using matplotlib that inlude these 
>>>> annoted "H" and "L" characters. In the application Ive seen, the 
>>>> process was most definitely automated, since it was applied to a 
>>>> large number of plots (i.e., the "H"'s and "L"'s werent added 
>>>> manually, since its not feasible). Unfortunately, the creators of 
>>>> these plots are not willing to share their technique.
>>>>
>>>> I dont know how to set this up with matplotlib.
>>>> Does anyone have any experience with this???
>>>> Is there any way to identify a "closed contour" & its value from a 
>>>> "contour class" that is returned from matplotlib's contour() 
>>>> function???
>>>>
>>>>
>>> Pablo: There is no easy way to do this in matplotlib. I guess you
>>> would try to find closed contours with no other contours inside them,
>>> the place the label at the center of that region. This might end up
>>> being quite tricky. I see from your example that there are many such
>>> regions that are not labelled (some are, some aren't).
>>>
>>> Or, you might just try to find local minima and maxima in your gridded
>>> data and plot H's and L's there. This ought to be easier.
>>>
>>> -Jeff
>>>
>>>
>> Pablo: Regarding the latter method, here's a relevant thread from the
>> scipy list:
>>
>> http://www.nabble.com/Finding-local-minima-of-greater-than-a-given-depth-td18988309.html 
>>
>>
>> -Jeff
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thank you very much for this (i include your code below).

one question about this: how can i remove the top x-axis and the right yaxis
from each of the marginal histograms? in other words, keep only the left
y-axis and the bottom x-axis of each of the histograms.

thank you.

mport numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import NullFormatter


x = np.random.randn(1000)
y = np.random.randn(1000)

nullfmt   = NullFormatter()         # no labels

left, width = 0.1, 0.65
bottom, height = 0.1, 0.65
bottom_h = left_h = left+width+0.02

rect1 = [left, bottom, width, height]
rect2 = [left, bottom_h, width, 0.2]
rect3 = [left_h, bottom, 0.2, height]

# start with a rectangular figure
#fig = plt.Figure( (8,8) )

axScatter = plt.axes(rect1)
axHistx = plt.axes(rect2)#, sharex=axScatter)
axHisty = plt.axes(rect3)#, sharey=axScatter)

axHistx.xaxis.set_major_formatter(nullfmt)
axHisty.yaxis.set_major_formatter(nullfmt)

axScatter.scatter(x,y)

bins = np.linspace(-4,4,21)
axHistx.hist(x, bins=bins)
axHisty.hist(x, bins=bins, orientation='horizontal')

axHistx.set_xlim( axScatter.get_xlim() )
axHisty.set_ylim( axScatter.get_ylim() )

plt.show()


On Mon, Feb 16, 2009 at 8:22 AM, Manuel Metz <mm...@as...>wrote:

> Attached is a very simple example that shows how to do something similar
> to scatterhist in matplotlib
>
> Manuel
>
> per freem wrote:
> > hello,
> >
> > is there a way to make a 2d scatter plot that includes (outside the axes)
> > histograms of the marginals of the two variables? like the matlab
> function
> > 'scatterhist'. see this for an example:
> >
> >
> http://www.mathworks.com/access/helpdesk/help/toolbox/stats/index.html?/access/helpdesk/help/toolbox/stats/scatterhist.html
> >
> > ideally i'd like the histograms outside the scatter plot to also have
> axes
> > so that the height of each histogram bar will be interpretable.
> > i understand that there's no command for this - but how can i construct
> it?
> >  i would not mind writing code to do this... if it's possible.  right now
> > this is the only thing keeping me from switching from matlab to
> matplotlib
> > exclusively since i use these graphs a lot
> >
> > thank you
> >
> >
> >
> > ------------------------------------------------------------------------
> >
> >
> ------------------------------------------------------------------------------
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> CA
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> >
> >
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> >
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>
>
>
>
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> CA
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> Enterprise
> -Strategies to boost innovation and cut costs with open source
> participation
> -Receive a $600 discount off the registration fee with the source code:
> SFAD
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>

Your code works fine for me with mpl 0.98.5.2.
What version of mpl are you using?

print matplotlib.__version__

-JJ



On Thu, Mar 5, 2009 at 12:03 PM, Erik Granstedt <egr...@gm...> wrote:
> Hello,
>
> I found an issue in working with subplots and using figlegend: it
> doesn't display markers.  This code illustrates the problem:
>
> x=r_[0.:11.:1.]
> y=x**1.5
> figure()
> subplot(211)
> line=plot(x,y,'sb-.')
> figlegend( (line,),('y',),'right' )
>
> Supplying the "numpoints" keyword to figlegend doesn't seem to have
> any effect, ie. I get the same results with:
> figlegend( (line,),('y',),'right',numpoints=10 )
>
> Is this the intended behavior?  Is there a good way to display the markers?
>
> I did find a workaround, but I don't think this is the ideal method:
> x=r_[0.:11.:1.]
> y=x**1.5
> figure()
> subplot(111)
> line=plot(x,y,'sb-.')
> figlegend( (line,),('y',),'right' )
> subplot(211)
> line=plot(x,y,'sb-.')
>
> Thanks,
>
> -Erik
>
> ------------------------------------------------------------------------------
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> -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise
> -Strategies to boost innovation and cut costs with open source participation
> -Receive a $600 discount off the registration fee with the source code: SFAD
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http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.bar

use

ax.set_xticks(ind+width*.5)

instead of

ax.set_xticks(ind+width)

-JJ






On Thu, Mar 5, 2009 at 1:40 PM, Timmie <tim...@gm...> wrote:
> Hello,
> I tried to modify the bar chart demo for my case.
> I want to plot only bar charts for one data set.
>
> But the xticklables are not centered below the bars, rather are they left in
> place as if there were still two data sets.
>
> How do I modify  set_xticklabels in oder to get the lables centered below the bar
> one data set?
>
> Thanks in advance,
> Timmie
>
>
> #### modified bar charts demo
>
>
> #!/usr/bin/env python
> # a bar plot with errorbars
> import numpy as np
> import matplotlib.pyplot as plt
>
> N = 5
> menMeans = (20, 35, 30, 35, 27)
> menStd =   (2, 3, 4, 1, 2)
>
> ind = np.arange(N)  # the x locations for the groups
> width = 0.35       # the width of the bars
>
> fig = plt.figure()
> ax = fig.add_subplot(111)
> rects1 = ax.bar(ind, menMeans, width, color='r', yerr=menStd)
>
> womenMeans = (25, 32, 34, 20, 25)
> womenStd =   (3, 5, 2, 3, 3)
> #~ rects2 = ax.bar(ind+width, womenMeans, width, color='y', yerr=womenStd)
>
> # add some
> ax.set_ylabel('Scores')
> ax.set_title('Scores by group and gender')
> ax.set_xticks(ind+width)
> ax.set_xticklabels( ('G1', 'G2', 'G3', 'G4', 'G5'), multialignment='left',
> position=(-2,0) )
>
> #~ ax.legend( (rects1[0], rects2[0]), ('Men', 'Women') )
>
> def autolabel(rects):
>    # attach some text labels
>    for rect in rects:
>        #~ print rect
>        height = rect.get_height()
>        print height
>        ax.text(rect.get_x()+rect.get_width()/2., 1.05*height, '%d'%int(height),
>                ha='center', va='bottom')
>
>
> autolabel(rects1)
> #~ autolabel(rects2)
>
> plt.show()
>
>
>
> ------------------------------------------------------------------------------
> Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA
> -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise
> -Strategies to boost innovation and cut costs with open source participation
> -Receive a $600 discount off the registration fee with the source code: SFAD
> http://p.sf.net/sfu/XcvMzF8H
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