Posts tagged "matplotlib" « SaltyCrane Blog

How to draw a simple line using python and the matplotlib API -

Date: 2007-01-05 | Tags: matplotlib, python

I'm continuing to learn the low level object oriented matplotlib API. My goal is to create very customizable, perfect plots. Here is how to draw a simple line. First create a figure that is 4 inches by 4 inches. Then create some axes with a 10% margin around each edge. Then add the axes to the figure. Then create a line from (0,0) to (1,1). Then add the line to the axes. Then create a canvase. Then create the .png file. Looks like good object oriented python fun to me...

""" line_ex.py                                             
 """                                                        
 from matplotlib.figure import Figure ...

How to use the pylab API vs. the matplotlib API

Date: 2007-01-04 | Tags: matplotlib, python

This article has a good description of the 2 API's in matplotlib: the pylab API and the matplotlib API. I've been using the pylab interface because it is easier, especially coming from a matlab background. But I wanted to get direct access to the matplotlib classes so I needed to use the matplotlib API. Here is a simple example that creates a .png figure using the 2 different API's.

Here is the example using the pylab API:

""" api_pylab.py          
 """                       
 from pylab import *       
 
 figure(figsize=[4,4])     
 axes([.1,.1,.8,.8])       
 scatter([1,2],[3,4])      
 savefig ...

How to create some derived arrow classes with matplotlib and python

Date: 2007-01-03 | Tags: matplotlib, python

Here is an example of how to create some derived arrow classes with matplotlib and python. The arrow() function in matplotlib accepts origin and delta x and delta y inputs. I changed this to polor coordinates so Arrow2 accepts the x and y coordinates of the origin, the length, and the angle. Then I created 4 classes derived from Arrow2 called ArrowRight, ArrowLeft, ArrowUp, and ArrowDown. These just set the angle for you to 0, 180, 90, and 270 respectively. Notice too that the **kwargs can be passed down so you can still set all the other parameters.

""" arrow_ex2.py ...

How to draw an arrow with matplotlib and python

Date: 2007-01-02 | Tags: matplotlib, python

Here is an example of how to draw an arrow with matplotlib. It should be
very easy, but I had to change the width setting so the arrow head would
not be too small. Further documentation is here:
http://matplotlib.sourceforge.net/matplotlib.pylab.html#-arrow

""" arrow_ex.py
"""
from pylab import *
figure()
axes()
arrow(.1,.1,.2,.2, width=0.01)
show()

Example pie charts using python and matplotlib

Date: 2006-12-19 | Modified: 2008-09-09 | Tags: matplotlib, python | 2 Comments

I needed to make some pie charts and didn't like the results I got from Excel. It was too hard to customize the plots exactly the way I wanted them. I have used Matlab before and I preferred Matlab to Excel. However, Python is my favorite thing to use so I searched for python and matlab on Google and found matplotlib. Matplotlib is a matlab-like plotting library for Python. You can get matplotlib from http://matplotlib.sourceforge.net/, but it is also bundled with the Enthought version of Python so I got it from there. Update: I realized that ... ... read more »