Healpy provides a python package to manipulate healpix maps. It is based on the standard numeric and visualisation tools for Python, Numpy and matplotlib.

To find find more information about Healpix, please visit its home page at http://healpix.sourceforge.net/.

The documentation can be found at http://healpy.readthedocs.org, tutorial at http://healpy.readthedocs.org/en/latest/tutorial.html.

• pixelisation manipulation (ang2pix, pix2ang, etc.)
• spherical harmonic transforms (map2alm, alm2map, synfast, anafast, etc. both for temperature and polarisation)
• plotting capabilities (mollweide and gnomonic projection)
• reading and writing of Healpix FITS maps and alm

• Python 2.6 or 2.7
• Numpy (tested with version >=1.5.0)
• Matplotlib
• Python development package is required for some distribution (e.g., python-dev package for Ubuntu)
• PyFITS

The quickest way to install Healpy is with pip (>= 1.4.2), which automatically fetches the latest version of Healpy and any missing dependencies:

pip install --user healpy

If you have installed with pip, you can keep your installation up to date by upgrading from time to time:

pip install --user --upgrade healpy

See INSTALL.rst for further details and other installation options.

Healpy depends on the Healpix C++ and cfitsio C libraries. Source code is include with Healpy and you do not have to install them separately.

However, if you have them installed already, Healpy should detect and reuse them instead of building them from source. To use your own installations of HEALPix and cfitsio, you will also need:

• pkg-config
• HEALPix autotools-style C++ package
• cfitsio

See INSTALL.rst for further instructions.

healpy pixel functions, e.g. ang2pix, do not support 32bit platforms, we are working on fixing this issue.

For specific HOWTO questions please create a question on StackOverflow and tag it with the healpy tag, so that answers will be easily searchable on google.

If you think you found a bug or you have install issues, open an issue on github: https://github.com/healpy/healpy/issues?state=open

For more general discussion, you can write to the healpy mailing list: https://groups.google.com/d/forum/healpy

Project development takes place on github, http://github.com/healpy/healpy, please open an issue over there for reporting bugs or suggest improvements. Collaboration is very welcome, just fork the project on github and send pull requests back to the main repository.

Core developers:

• Cyrille Rosset
• Andrea Zonca
• Martin Reinecke

Contributors:

• Pierre Chanial
• Yu Feng
• Duncan Hanson
• Sergey Koposov
• Maude Martin Lejeune
• Paul Price
• Leo Singer
• Maurizio Tomasi

Note that, as stated here publications based on work using the HEALPix software package should include both of the following:

1. an acknowledgment statement: "Some of the results in this paper have been derived using the HEALPix (Górski et al., 2005) package". The complete reference is:

   Górski, K.M., E. Hivon, A.J. Banday, B.D. Wandelt, F.K. Hansen,

   M. Reinecke, and M. Bartelmann, HEALPix: A Framework for High-resolution Discretization and Fast Analysis of Data Distributed on the Sphere, Ap.J., 622, 759-771, 2005.

2. at the first use of the HEALPix acronym, a footnote placed in the main body of the paper referring to the HEALPix web site, currently http://healpix.sf.net

As healpy is based on HEALPix Software (the C++ library), the same condition applies to it.