Source code for irfpy.jdc.fov1

''' JDC fov module (16 azim 4 elev version)

It is not yet clear the exact FOV of JDC.
However, we need some model for it.

Here we assume 90x360 (half-hemisphere) for full view,
with 4x16 bin separations.
This will give you 22.5 degrees resolution.
FWHM of 22.5 deg is also assumed.
'''
import numpy as np

def elev_pix_center(nel):
    r''' Elevation pixel center in degrees.

    The JDC has two units.  Number definition is
    0 as the zenith looking, and 3 as horizontal looking.
    The definition of angle, :math:`\theta` is 0 for zenith looking
    and 90 is horizontal looking.

    .. note::

        The numbering definition is opposite from :mod:`irfpy.jdc.fov0`.

    Thus, the expression is

    .. math::

        \theta = 22.5 * nel + 11.25


    :param nel: Number of elevation.  0 to 3 (or more in general from -0.5 to 3.5).
    :type nel: ``int``, ``float`` or ``np.array``.
    :return: The elevation angle in degrees.
    :rtype: ``np.array``

    Note that the ``nel`` is usually ``int`` or ``np.array`` with
    ``dtype=np.int``, but ``float`` may also be allowed for special use.


    >>> print(elev_pix_center(0))
    11.25
    >>> print(elev_pix_center(2))
    56.25
    >>> print(elev_pix_center([-0.5, 3.5]))
    [ 0. 90.]

    Note also that the returned type is np.array object, even
    the given parameter is a scalar.  In this case, np.array object
    with shape ``()`` is returned.

    >>> print(elev_pix_center(3.5).shape)
    ()
    '''
    return 11.25 + 22.5 * np.array(nel)

def elev_pix_fwhm(nel):
    ''' Return the FWHM

    Always 22.5
    '''
    return 22.5 + np.zeros_like(nel)

def azim_pix_center(naz):
    r''' Return the azimuthal angle for the given channel number(s).

    Similar to :meth:`elev_pix_center`, the azimuthal angle,
    :math:`\phi` is returned.

    .. math::

        \phi = naz * 22.5 + 11.25

    >>> print(azim_pix_center(0))
    11.25
    >>> print(azim_pix_center(15))
    348.75
    >>> print(azim_pix_center([6, 7, 8]))
    [146.25 168.75 191.25]
    '''
    return np.array(naz) * 22.5 + 11.25

def azim_pix_fwhm(naz):
    ''' Return the FWHM

    For draft, I just return 19.5 for simplicity.
    '''
    return 22.5 + np.zeros_like(naz)