Visualization
=============

The HealPixProjection routines can easily be used to display a full sky map with different projections. In the :mod:`hpproj.visu` module, several projection have been implemented

.. plot::
   :include-source:

   import matplotlib.pyplot as plt
   import numpy as np
   import healpy as hp
   from astropy.wcs import WCS
   from hpproj import mollview

   # Ring like healpix map
   nside = 2**6
   hp_map = np.arange(hp.nside2npix(nside))
   hp_header = {'NSIDE': nside,
                'ORDERING': 'RING',
                'COORDSYS': 'G'}

   # Projection of the map and plotting
   _ = mollview(hp_map, hp_header)
   fig = plt.figure()
   ax = fig.add_subplot(1,1,1, projection=WCS(_.header))
   ax.imshow(_.data, origin='lower', interpolation='none')
   ax.grid()
   ax.set_title('mollview')

Note that these maps have a proper :class:`~astropy.wcs.WCS` header and thus can be easily used to overplot markers and artists.

Other classical projections have been implemented

.. plot::

   import matplotlib.pyplot as plt
   import numpy as np
   import healpy as hp
   from astropy.wcs import WCS
   from hpproj import carview, orthview, \
    merview, coeview, bonview, pcoview, tscview


   # Ring like healpix map
   nside = 2**6
   hp_map = np.arange(hp.nside2npix(nside))
   hp_header = {'NSIDE': nside,
                'ORDERING': 'RING',
                'COORDSYS': 'G'}

   # Projection of the map and plotting
   for view in [carview, merview, coeview, bonview, pcoview, tscview]:
       fig = plt.figure()
       _ = view(hp_map, hp_header)
       ax = fig.add_subplot(1,1,1, projection=WCS(_.header))
       ax.imshow(_.data, origin='lower', interpolation='none')
       ax.grid()
       ax.set_title(view.__name__)