In this page you can download the drizzling software library, which reprojects data from HEALPix to local WCS, in IDL and Python languages. The drizzling library uses a strategy where the surface of pixel intersection is computed as presented in Appendix A of Paradis et al., 2012, A&A, 543, 103. This method allows fast ingestion and guarantees the photometric accuracy of the transformation with minimal data loss during the transformation from HEALPix to local WCS FITS.

NEW You can now access a web interface to reproject data from HEALPix to local WCS http://drizzweb.irap.omp.eu/

IDL version


  • Jean-Philippe Bernard (IRAP)
  • Nathalie Baby (IRAP)
  • Caroline Bot (CDS)
  • Laurent Cambrésy (CDS)
  • Déborah Paradis (IRAP)
  • Alexandre Sauvé (IRAP)


Python version


  • Antoine Goutenoir (IRAP)
  • Déborah Paradis (IRAP)
  • Jean-Michel Glorian (IRAP)
  • Gabriel Foënard (IRAP)
  • Nathanael Jourdane (IRAP)
  • Anaïs Amato (IRAP)

Source and Download

The source tree is available on gitlab.

The python package itself can be downloaded an installed via pip :

pip install drizzlib

Or you can directly grab a tarball here :

:!: There are detailed instructions and troubleshooting tips in the README, which you should read.


Here's a simple usage example, that reads my_healpix.fits and extracts a subset of its data as described by the header in wcs_config.fits, and writes the result into my_wcs.fits :

from drizzlib import healpix2wcs

Installation Details

First, install the system dependencies :

Debian / Ubuntu
apt-get install python-dev pkg-config libfreetype* gfortran libopenblas-dev liblapack-dev

The easy way

pip install drizzlib
:?: It may complain about numpy. Install it, and try again.

The other way

Uncompress the tarball, move into it.

Then, install the python dependencies using pip :

pip install --upgrade setuptools
pip install -r requirements.txt

Finally, install drizzlib itself :

python setup.py install

Old version

Only for python 2.7