matplotlib-users Mailing List for matplotlib (Page 2)

I am trying to create a figure that plots a data matrix with matshow and has x tick labels corresponding to the x dimension of the matrix.  The x dimension is a series of floats, but they don't correspond to the data matrix cell index values (0,1,2…) that make up what matplotlib obviously thinks are the x values for the plot.  Is there a way that I can set the x tick labels so that they will be laid out and formatted in the normal way for numbers on the x-axis?  It would be great if they also scaled in the normal way when the plot is manipulated in the little gui window.

Thanks for the help.

Hi all,

I have a plot in which I have 15 markers, each with a separate size
(created by calls to plot()). Because of this, the legend also shows
variable size by default but I'd like all markers in the legend to have the
same size.

I'm looking for an alternative to manually calling plot again with a
standardized marker size (say 10.0) but plotting offscreen or with NANs.
Thoughts I had were to either change the marker sizes after the legend is
drawn (but it seems very difficult to update a legend post-creation) or to
copy the handles and change the size that way (but I've yet to figure out
how to make a hard copy of the plot handles). Any solutions?

-- 
Matthew Niznik

On 3 December 2013 14:50, jilguero <jil...@gm...> wrote:
> I am trying to make plots by using matplotlib.pyplot (within a Python
> script) to be used in a web site (apache, and PHP). I am using Ubuntu
> 12.04.3. The script works fine when run from the command line (it is able to
> generate the image with "savefig"), but when the script doesn't work when
> run from PHP under an apache request. I have found a similar problem in this
> post:
> http://matplotlib.1069221.n5.nabble.com/savefig-fails-under-apache-on-solaris-td15122.html
>
> Finally, I have found the solution in this web:
> http://texnological.blogspot.com.es/2013/01/how-to-execute-python-matplolib-pylab.html
>
> The solution consists on importing matplotlib in this way:
>   # To import pylab
>   os.environ[ 'MPLCONFIGDIR' ] = '/tmp/'
>   import matplotlib
>   matplotlib.use('agg')
>   import pylab
>
> This works for me, but I don't know whether this is a bug and it has to be
> reported anywhere. The best option should be to import it in a regular way
> (such as import matplotlib.pyplot as plt), and this can be confusing for a
> lot of people. Well, let me know. Thank you.

Check out http://matplotlib.org/faq/howto_faq.html#matplotlib-in-a-web-application-server

Cheers,
Scott

Hi,

I am trying to make plots by using matplotlib.pyplot (within a Python
script) to be used in a web site (apache, and PHP). I am using Ubuntu
12.04.3. The script works fine when run from the command line (it is able to
generate the image with "savefig"), but when the script doesn't work when
run from PHP under an apache request. I have found a similar problem in this
post:
http://matplotlib.1069221.n5.nabble.com/savefig-fails-under-apache-on-solaris-td15122.html

Finally, I have found the solution in this web:
http://texnological.blogspot.com.es/2013/01/how-to-execute-python-matplolib-pylab.html

The solution consists on importing matplotlib in this way:
  # To import pylab
  os.environ[ 'MPLCONFIGDIR' ] = '/tmp/'
  import matplotlib
  matplotlib.use('agg')
  import pylab

This works for me, but I don't know whether this is a bug and it has to be
reported anywhere. The best option should be to import it in a regular way
(such as import matplotlib.pyplot as plt), and this can be confusing for a
lot of people. Well, let me know. Thank you.

Best regards,

Jilguero.







--
View this message in context: http://matplotlib.1069221.n5.nabble.com/images-for-web-sites-tp42581.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

On 2013/12/01 5:11 AM, lin...@eu... wrote:
> Z = X**2 + Y**2
> Z[(X**2+Y**2 < r**2) | (X**2+Y**2 > R**2)] = np.ma.masked

The problem is that Z is not a masked array.  Change the first line 
above to Z = np.ma.array(X**2 + Y**2).

Also, use pcolormesh instead of pcolor.  Pcolormesh is much faster.

Eric

see http://matplotlib.1069221.n5.nabble.com/cmap-set-bad-not-showing-any-effect-with-pcolor-td27530.html

On Dec 1, 2013, at 10:11 AM, lin...@eu... wrote:

> Hi,
> 
> I m trying to plot some data with pcolor. The data should be plotted on a ring. Inside and outside of the ring should be white area. However, now I have black area. Where is my mistake? Minimal working example:
> 
> from matplotlib import cm
> import matplotlib.pyplot as plt
> from pylab import *
> 
> import numpy as np
> import scipy as sp
>    
> X = np.arange(-1.0, 1.01, 0.01)
> Y = np.arange(-1.0, 1.01, 0.01)
> X, Y = np.meshgrid(X, Y)
> 
> [r, R] = [0.25, 1.0]
> an = sp.linspace(0,2*sp.pi,100)
> 
> fig = plt.figure(1, figsize=(6,6))
> 
> ax = fig.add_subplot(111, aspect = 'equal')
> Z = X**2 + Y**2
> Z[(X**2+Y**2 < r**2) | (X**2+Y**2 > R**2)] = np.ma.masked
> cm.hot.set_bad('white', alpha=None)
> plot = pcolor(X, Y, Z, cmap=cm.hot)


I think part of the problem is that Z is not a masked_array.  This works for me.  I set_bad to green to show the effect.  

Z = np.ma.masked_array(X**2 + Y**2, 
                       mask = (X**2+Y**2 <= r**2) | (X**2+Y**2 > R**2))
cm.hot.set_bad('green', alpha=None)
plot = pcolormesh(X, Y, Z, cmap=cm.hot)

> plt.plot(r*sp.cos(an), r*sp.sin(an), 'k')
> plt.plot(R*sp.cos(an), R*sp.sin(an), 'k')
> axis([-1.0, 1.0, -1.0, 1.0])
> 
> plt.show()

Hi,

I m trying to plot some data with pcolor. The data should be plotted on a ring. Inside and outside of the ring should be white area. However, now I have black area. Where is my mistake? Minimal working example:

from matplotlib import cm
import matplotlib.pyplot as plt
from pylab import *

import numpy as np
import scipy as sp
    
X = np.arange(-1.0, 1.01, 0.01)
Y = np.arange(-1.0, 1.01, 0.01)
X, Y = np.meshgrid(X, Y)

[r, R] = [0.25, 1.0]
an = sp.linspace(0,2*sp.pi,100)

fig = plt.figure(1, figsize=(6,6))

ax = fig.add_subplot(111, aspect = 'equal')
Z = X**2 + Y**2
Z[(X**2+Y**2 < r**2) | (X**2+Y**2 > R**2)] = np.ma.masked
cm.hot.set_bad('white', alpha=None)
plot = pcolor(X, Y, Z, cmap=cm.hot)
plt.plot(r*sp.cos(an), r*sp.sin(an), 'k')
plt.plot(R*sp.cos(an), R*sp.sin(an), 'k')
axis([-1.0, 1.0, -1.0, 1.0])

plt.show()