matplotlib-users Mailing List for matplotlib

On Friday, January 28, 2011, Thomas Lecocq <thl...@ms...> wrote:
>
>
>
>
>
>
> From: patbradf
> To: mat...@li...
> Date: Wed, 26 Jan 2011 22:53:28 -0600
> Subject: [Matplotlib-users] Problem with "projection='3d'"
>
> Forgive me if this is an old question, but I just loaded mplot3d and was attempting to work through a couple of the examples on the Matplotlib website.  The problem is that whenever I try to make a call to a function that requires an argument of projection=’3d’ (such as:   ax = fig.add_subplot(111, projection='3d')), Python gives me the following error: Traceback (most recent call last):  File "<pyshell#12>", line 1, in <module>    ax = fig.add_subplot(111, projection='3d')  File "C:\Python26\lib\site-packages\matplotlib\figure.py", line 677, in add_subplot    projection_class = get_projection_class(projection)  File "C:\Python26\lib\site-packages\matplotlib\projections\__init__.py", line 61, in get_projection_class    raise ValueError("Unknown projection '%s'" % projection)ValueError: Unknown projection '3d'
>
> Check the version of matplotlib you have ! , I suspect a <=1.0
> HTH
> Thom
>  		 	   		
>

If your version is less than 1.0, the the 3D examples will not work as
is.  Instead of gca() with the projection argument, you need to make
an Axes3D object instead.

fig = plt.figure()
ax = Axes3D(fig)

Or something like that (I am working off memory right now).

Ben Root

Hi all,

I have a derived class that I copy-pasted from the web somewhere to hide
some tick labels:

class MinorLogTickFormatter(matplotlib.ticker.LogFormatter):
    # Format log scale with 10^ labels. Only if show one label over two.
    def __call__(self, val, pos=None):
        exponent =
int(numpy.floor(numpy.log(abs(val))/numpy.log(self._base)))
        base = int(val / 10.0**exponent)
        isDecade = self.is_decade(exponent)
        if not isDecade and self.labelOnlyBase:
            return ''
        if (not (base == 2 or base == 4 or base == 6 or base == 8)): # Only
show these ones.
            return ''
        label = r"$%d \times 10^{%d}$" % (base, exponent)
        return label

pylab.gca().xaxis.set_minor_formatter(MinorLogTickFormatter())

I've beend using this since many months, but with matplotlib 1.0.1 I can't
anymore. It complains about the is_decade() function:
isDecade = self.is_decade(exponent)
AttributeError: MinorLogTickFormatter instance has no attribute 'is_decade'

How can I fix that?

Thanks!

Nicolas

2011/1/28 Mike Alger <ma...@ry...>

> Philip,
>
>
>
> A few questions before I give one possible solution,
>
>
>
> Does this plot need to be updated in real time ? or is this plot to be done
> in post processing?
>
>
>
> if you can do the plots with post processing you should be able to use
> pcolor function to do your tasks
>
> http://matplotlib.sourceforge.net/examples/pylab_examples/pcolor_demo.html
>
>
>
> i won’t go into details but just assign:
>
>
>
> X as 1d vector with your m/z values
>
> Y as 1d vector  your time values
>
> And Z as a 2d array that will map counts/sec to both a “m/z” and “time”
> index
>
>
>
> You will have to find the location for your other marks and then plot them
> on top of pcolor graph but that shouldn’t be too hard  just express your
> values (i am assuming 3dB cutoff points and peak power of some sort) in
> terms of X Y. I am almost certain there is probably a nice DSP way to solve
> for those X Y values once the data is in a 2d array but i am no expert on
> that mater.
>
>
>
> Good luck and hopefully this helps,
>
>
>
> Mike
>

hi mike,

thanks for the answer. it looks interesting, but will it work if the m/z
values are all different from each other? i mean: the m/z-ranges are
overlapping, but there are no duplicate values. this way, every column of
the array would only contain one value if i understood you correctly.

thanks,
philipp

From: patbradf
To: mat...@li...
Date: Wed, 26 Jan 2011 22:53:28 -0600
Subject: [Matplotlib-users] Problem with "projection='3d'"



Forgive me if this is an old question, but I just loaded mplot3d and was attempting to work through a couple of the examples on the Matplotlib website.  The problem is that whenever I try to make a call to a function that requires an argument of projection=’3d’ (such as:   ax = fig.add_subplot(111, projection='3d')), Python gives me the following error: Traceback (most recent call last):  File "<pyshell#12>", line 1, in <module>    ax = fig.add_subplot(111, projection='3d')  File "C:\Python26\lib\site-packages\matplotlib\figure.py", line 677, in add_subplot    projection_class = get_projection_class(projection)  File "C:\Python26\lib\site-packages\matplotlib\projections\__init__.py", line 61, in get_projection_class    raise ValueError("Unknown projection '%s'" % projection)ValueError: Unknown projection '3d'

Check the version of matplotlib you have ! , I suspect a <=1.0
HTH
Thom
 		 	   		  

On Wednesday, January 26, 2011, Soumyaroop Roy <sou...@gm...> wrote:
> Hi Ben:
>
> That's encouraging!
>
> I want to be able plot up to N data points (the points are in an
> ordered sequence) on a canvas and then zoom into the plot region
> enclosed within a subset sequence (e.g., T1 to T2 data points, 0 <= T1
> < T2 <=N) by putting two cursors - one on T1 and the other one on T2.
>
> regards,
> Soumyaroop
>

One way to do that would be to set the x and/or y limits based on the
min/max of the slice of data you want to view.  For example:

import numpy as np
Import matplotlib.pyplot as plt

X = np.linspace(0, 5*np.pi, 100)
Y = np.sin(X)
plt.plot(X, Y)

iStart = 50
iEnd = 78

plt.xlim(X[iStart:iEnd].min(), X[iStart, iEnd].max())
plt.ylim(Y[iStart:iEnd].min(), Y[iStart, iEnd].max())

plt.show()

Philip, 

 

A few questions before I give one possible solution, 

 

Does this plot need to be updated in real time ? or is this plot to be done in post processing?

 

if you can do the plots with post processing you should be able to use pcolor function to do your tasks 

http://matplotlib.sourceforge.net/examples/pylab_examples/pcolor_demo.html 

 

i won’t go into details but just assign:

 

X as 1d vector with your m/z values 

Y as 1d vector  your time values

And Z as a 2d array that will map counts/sec to both a “m/z” and “time” index

 

You will have to find the location for your other marks and then plot them on top of pcolor graph but that shouldn’t be too hard  just express your values (i am assuming 3dB cutoff points and peak power of some sort) in terms of X Y. I am almost certain there is probably a nice DSP way to solve for those X Y values once the data is in a 2d array but i am no expert on that mater. 

 

Good luck and hopefully this helps, 

 

Mike 

  

 

From: Philipp A. [mailto:fly...@we...] 
Sent: January-27-11 5:15 PM
To: mat...@li...
Subject: [Matplotlib-users] 3D Data to 2d Plots

 

Hi list,

I want to visualize Plots over time.

 

This describes the data:

 3dplot.png <http://red-sheep.de/images/3dplot.png> 

 

a) and b) are single scans, the cutting at the red bars is no problem.

c) illustrates how they are done over time.

d) is what I want. I think this plot <http://matplotlib.sourceforge.net/examples/axes_grid/demo_axes_grid2.html>  could be a starting point, but I don’t really understand what’s done there.

e) would be easier to do, like this plot <http://matplotlib.sourceforge.net/examples/mplot3d/polys3d_demo.html> , but information is lost this way (hidden behind higher values)

 

it would be best to do the following:

1. plot one horizontal line vertically above each other (gapless), one for each scan (so the vertical axis is the time axis)

2. each line is displayed as a series of gradients directly next to to each other (gapless)

3. the starting and ending point of each gradient are determined by the horizontal position of two adjacent data points in the current scan

4. the colors of each gradient are determined by the vertical position of the two adjacent data points in the current scan, relative to the total maximum

 

has anyone an idea how to do this? i am really a matplotlib noob.

Philipp

On 1/27/11 6:35 AM, Thomas Lecocq wrote:
> Hi all,
>
> I would like to contribute to a better readshapefile method, who 
> should I contact / where should I commit ?
>
> First improvement and partial solution :
>
> * returning a tuple of linecollections per "record", with its name and 
> other properties.
>
> Cheers,
>
> Thomas
>
> ps : example 
> http://www.geophysique.be/2011/01/27/matplotlib-basemap-tutorial-07-shapefiles-unleached/
>
> **********************
> Thomas Lecocq
> Geologist
> Ph.D.Student (Seismology)
> Royal Observatory of Belgium
> **********************
>
Thomas:  If you could check out basemap from svn, add your changes, then 
create an svn diff, that would be ideal.  You either send the diff 
directly to me, or post it on the list.  Thanks.

-Jeff