[Matplotlib-users] how to reduce the file size of plots generated with matplotlib

[Christopher K. <cku...@vb...>]

Hello:

I use matplotlib to generate x-y data plots; i.e., 2-D plots.  The problem is that the output files (the PDF files containing plots that are generated with matplotlib) are huge.  I can generate files that are 100's of KB or even MBs.  This seems absurd to me.  These file sizes cause programs that use them to come to a grinding halt.  My goal is to reduce the plot files that I produce with matplotlib.  Details follow.


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I use matplotlib from EPD.
Enthought Canopy Python 2.7.3 | 64-bit | (default, Aug  8 2013, 05:37:06) 

Matplotlib version:
>>> print matplotlib.__version__
1.3.0

OS:
I'm using Mac OS X Version 10.8.4.

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I use a home-grown code whose starting point was an example code on matplotlib website.

My relevant imports are:

import numpy
import scipy
import pylab
import matplotlib.pyplot as plt
import matplotlib

My plotting code lines are:


        ## PDF.
        outfile = "basefile" + ".pdf"
        ## pylab.savefig(outfile, bbox_inches=0)
        pylab.savefig(outfile,bbox_inches='tight')


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My PDF files contain simple plots which consist of (a) data points only, (b) lines between data points (data points not plotted), or (c) both data points and lines.

I have a consistent problem in that the files produced have sizes that seem way too big.
For example, most recently, I am plotting 3 data sets; each data set has about 90,000 points.  If I plot all three sets in one PDF figure, the file size is over 2MB.
This seems absurd to me.  I used R plotting for many years (again, my own homegrown code, for 6 years) and never had this issue, and I was making these kinds of plots/figures.

I thought it may be a vector/raster issue, but the following web page says that PDF are generated as vector image, which, to my understanding (which could be wrong), is the more compact format.
http://matplotlib.org/faq/usage_faq.html

Is there a command I can use to reduce the file size?  Since I am using these in reports and publications, the figures are almost always less than 3 inches by 3 inches in size; i.e., I do not have issues about taking a raster figure and trying to blow it up.  So I am not concerned about pixelation problems that occur when an image is increased in size.

Thank you very much.

c