Welcome to HealPixProjection’s documentation!

HealPixProjection is a project to allow easy and efficient projection of healpix maps onto planar grids. It can be used as a standalone program hpproj.cutsky()

$ cutsky 0.0 0.0 --mapfilenames HFI_SkyMap_857_2048_R2.00_full.fits

or as a python function

from hpproj import cutsky
result = cutsky([0.0, 0.0], maps={'HFI 857': {'filename': 'HFI_SkyMap_857_2048_R2.00_full.fits'}})

or as a python class, for optimization when producting several cuts

from hpproj import CutSky, to_coord
cutsky = CutSky({'Planck 857': {'filename': 'HFI_SkyMap_857_2048_R2.00_full.fits'}})
result = cutsky.cut_fits(to_coord([0., 0.])


For science applications requiring high photometric accuracy, we recommend the drizzlib software developed by CADE, which uses a flux-conserving drizzling method to reproject data between HEALPix and local WCS. Drizzlib is available as standalone software (IDL python) here: http://cade.irap.omp.eu/dokuwiki/doku.php?id=software . An online interface, drizzweb, is available here: http://drizzweb.irap.omp.eu/ .

You can also have a look into the reproject.reproject_from_healpix() function from the reproject package.


  • Galactic and equatorial system supported
  • All projection system from wcs
  • Project several healpix maps at once, efficiently !
  • Output in fits, png or votable
  • Perform n-dim projections !

See Basic Usage for more information on how to use cutsky


Install hpproj using pip :

$ pip install hpproj

or by running setuptools on source. For more information see the installation page.


If you are having issues, please let us know.


This project is licensed under the LGPL+3.0 license.

Indices and tables