How to use Matplotlib in Python 2.6 installed by default ArcGIS 10.0 installation?

Question

I am wondering if anyone has successfully run Matplotlib with the default installation of Python 2.6 that comes Arcgis 10.0. It does not seem to work with the python version installed by Arcgis 10.0. I was able to download and successfully run other packages such as Scipy. I have looked at many blogs where they talk about using other installations of python such as Python(x,y) etc. I prefer to run it without changing the version of python. Please post the details of the steps if anyone was successful in running Matplotlib. I have installed Matplotlib version 1.1.0. For example, the following command to check version works.

import matplotlib

print matplotlib.version shows 1.1.0

I think the problem is with other things that comes with Matplotlib such as pylab, pyplot. Every time I try to import pylab or pyplot, the python IDLE environment is RESTARTED. Please give me the details of steps (from download, installation to running it) if anyone of your are successful in using with the default python installation of ArcGIS 10.0.

Answer 1

There are two ways to solve the situation of yours:

1) Allowing no minor modifications

Then you will have to be happy with an older version of matplotlib. You can, as you probably already know, download other versions from here: matplotlib @ SourceForge. For example, matplotlib v1.0.1 should only require NumPy v1.1, and ArcGIS 10.0 comes shipped with NumPy v1.3.0.

2) Allowing minor modifications

You can easily replace the NumPy site-package with the most recent release and then happily use the already installed matplotlib you've chosen. Simply remove the folder C:\Python26\ArcGIS10.0\Lib\site-packages\numpy and then download and then install the most recent version from the official NumPy website. I've been doing this myself and have had no problems with ArcGIS after doing so a few months ago.

You can find some more information about all this here.

Hope that helps!

Answer 2

It should, theoretically, just work. Where is it failing? Does it fail to install? Does it fail to import? Is it failing to inport in python.exe or just in Arcmap? There is a fairly well-known issue with an Arcmap session not importing certain C extensions (namely ones built with the built-in distutils) due to the fact that the PYDs have an embedded manifest that requires a different version of the MSVC runtime DLLs than what Arcmap has already loaded into memory in the process.

There's an issue on the python.org bug tracker related to this, but it looks like manifests have been ping-ponged in and out of the Windows build process enough times that it will not be changed again. The alternative is to find a different install of matplotlib without the embedded manifest (maybe try to see if the installer on this page works for you?) or to patch distutils yourself on your local machine and built it yourself assuming that this manifest thing is indeed the issue.