matplotlib-users Mailing List for matplotlib

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

Hi clolern2,

> - for some reason a TZ has been inserted

Datetime values are stored as numbers. Timezone info is added when that numbers are converted again into datetimes for labelling.

> - graphs have white space buffers on either side of the X-axix

You can use axes.xlim in order to adjust it.

> - points on X-axis are separated by the hour, instead of values in datetime
> object

Matplotlib automagically chooses a format depending on the scale but you
can specify a format:

import matplotlib.dates as mdates
...
xaxis.set_major_formatter(mdates.DateFormatter('%Y-%b-%d %H:%M'))

Goyo

El mié, 11-02-2009 a las 09:38 -0800, collern2 escribió:
> Hi,
> 
> I've managed to take the contents of my CSV file and display it with
> matplotlib. I'm having some issues with the way my X-axis is being
> displayed.
> 
> For the X-axis, I pass in a list that filled with datetime objects, an
> example of one element on the list:
> 
> datetime.datetime(2007, 12, 17, 20, 28, 15),
> 
> Issues (please see the attached cpu.png:
> 
> - for some reason a TZ has been inserted
> - graphs have white space buffers on either side of the X-axix
> - points on X-axis are separated by the hour, instead of values in datetime
> object
> 
> I have tried many variations of plotdate, etc. If someone could please point
> me in the right direction.
> 
> Thanks
> 
> =================
> Code http://www.nabble.com/file/p21958283/cpu.png 
> =================
> 
> #!/usr/bin/env python
> 
> import csv
> import sys
> import matplotlib.pyplot as plt
> import datetime
> 
> new_list = []
> time = []
> cpu = []
> 
> fileReader = csv.reader(open("sample.csv", "rb"))
> for row in fileReader:
>     new_list.append(row)
> 
> # Converts papatimes time format into dattime
> def time_split(current_line):
>     # splits papastats datetime format in useable python list
>     dt = datetime.datetime.strptime(current_line[0],"%Y/%m/%d %H:%M:%S")
>     time.append(dt)
> 
> def cpu_calc(current_line):
>     cpu.append(current_line[11].rstrip("%"))
> 
> #Iterate over list of CSV values
> for i in new_list[1:]:
>     time_split(i)
>     cpu_calc(i)
> 
> plt.plot(time, cpu, 'b-')
> #plt.plot_date(time, cpu, fmt='b-', xdate=False, ydate=False, tz=None)
> 
> plt.xlabel('Time')
> plt.ylabel('CPU %')
> plt.title('Daily CPU Usage')
> plt.grid(True)
> plt.grid(alpha=0.2, color='black', linestyle='-', linewidth=0.1)
> plt.show()
> 

hi,

I'm using polar bars to plot windroses. Since the 0.98.5 version i have
some issues with the plots.
The 0° bar is not displayed in the good way. This bar is
located between -0.26 radian and 0.26 radian but it is printed
counterclockwise.
It was working perfectly with matplotlib version 0.98.3. I just switched to
version 0.98.5 because of the NaN bug of the previous version.

Any idea how i could make it work again ?
Ty!!

from pylab import *
nb_secteur=12

fig = figure(2,figsize=(8,8))
ax = fig.add_axes([0.1, 0.1, 0.8, 0.8], polar=True,)

thetagrids([90,45,0,315,270,225,180,135],
labels=["N","NE","E","SE","S","SO","O","NO"])
theta = arange(0.0-pi/nb_secteur, 2*pi-pi/nb_secteur, 2*pi/nb_secteur)

radii = [10.,20,10,5,3,4,3,4,6,4,2,9]

width = 2*pi/nb_secteur

bars = ax.bar(theta, radii, width=width, bottom=0.0 )
for r,bar in zip(radii, bars):
bar.set_facecolor( 'blue')
bar.set_alpha(0.3)

text(1,0.69,"%",transform = ax.transAxes)
show()

Thanks Michael & Ryan!
Worked great!
amb


-----Original Message-----
From: Michael Droettboom [mailto:md...@st...]
Sent: Fri 2/13/2009 1:14 PM
To: Lewis, Ambrose J.
Cc: mat...@li...
Subject: Re: [Matplotlib-users] x axis & imshow...
 
You can pass "extent=(left, right, bottom, top)" to imshow to specify 
what the pixels in the array correspond to in data space.

Mike

Lewis, Ambrose J. wrote:
>
> Hi All:
>
> I'm working on a wxPython GUI that uses matplotlib.
>
> This program reads "chunks" of a data file into a numpy array and than 
> plots it using imshow.
>
> The first chunk works great. But, when I load chunks 2 to N, how can I 
> specify the different values for the labels on the x axis?
>
> I tried using "axes.set_xlim". This did reposition the x axis as 
> hoped, but the data is always being drawn back at the "zero" offset.
>
> Is there a way to tell the axis to map the array to a different x range?
>
> I can't read the whole file at once, it's just too big
>
> THANXS
>
> amb
>
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>
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-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA