You can either install cf_units using the conda package manager or from source.

Installing using conda
----------------------

cf_units is available using conda for the following platforms:
 * Linux 32-bit and 64-bit,
 * Mac OSX 64-bit, and
 * Windows 32-bit and 64-bit.

To install cf_units using conda, you must first download and install conda,
for example from http://conda.pydata.org/miniconda.html.

Once conda is installed, you can install cf_units using conda on any platform with
the following command::

  conda install -c scitools cf_units

Further documentation on using conda and the features it provides can be found
at http://conda.pydata.org/docs/intro.html.


Installing from source
----------------------

The latest cf_units source release is available from
https://github.com/SciTools/cf_units.

cf_units makes use of Numpy, netCDF4-python, and Unidata udunits2. These
dependencies must be in place before you can successfully install
cf_units. Once you have satisfied the requirements detailed below,
extract the cf_units source package, cd to the new directory, and enter::

  python setup.py install


Build and runtime requirements
==============================
These are external packages which you will need to have installed before
installing and running cf_units.

Many of these packages are available in Linux package managers
such as aptitude and yum. For example, it may be possible to install
Numpy using::

  apt-get install python-numpy

If you are installing dependencies with a package manager on Linux,
you may need to install the development packages (look for a "-dev"
postfix) in addition to the core packages.

python 2.7 or later (http://www.python.org/)
    cf_units requires Python 2.7 or later, but is not currently compatible with
    Python 3.

numpy 1.6 or later (http://numpy.scipy.org/)
    Python package for scientific computing including a powerful N-dimensional
    array object.

netcdf4-python 0.9.9 or later (http://netcdf4-python.googlecode.com/)
    Python interface to the netCDF version 4 C library.

udunits2 2.1.24 or later
    (http://www.unidata.ucar.edu/downloads/udunits/index.jsp)
    C library for units of physical quantities.

setuptools 0.6c11 or later (http://pypi.python.org/pypi/setuptools/)
    Python package for installing/removing python packages.


Optional
''''''''
These packages are required for the full cf_units test suite to run.

pep8 1.4.6* (https://pypi.python.org/pypi/pep8)
    Python package for software testing.

nose 1.1.2 or later (http://nose.readthedocs.org/en/latest/)
    Python package for software testing.

* Those packages have been tested with a specific build.


Custom site configuration
=========================
The default site configuration values can be overridden by creating the file
``cf_units/etc/site.cfg``. For example, the following snippet can be used to
specify a non-standard location for your udunits library::

  [System]
  udunits2_path = /path/to/libudunits2.so

An example configuration file is available in ``cf_units/etc/site.cfg.template``.
See :py:func:`cf_units.config` for further configuration options.


Packaged distributions
======================
The Enthought Python Distribution (EPD)
http://www.enthought.com/products/epd.php for Windows, OS X or
Redhat provides some of the dependencies for cf_units as does `Python (x, y)
http://www.pythonxy.com/ which tends to be updated a
bit more frequently.
