Source code for jdaviz.core.validunits
from astropy import units as u
__all__ = ['units_to_strings', 'create_spectral_equivalencies_list',
'create_flux_equivalencies_list']
[docs]
def units_to_strings(unit_list):
"""Convert equivalencies into readable versions of the units.
Parameters
----------
unit_list : list
List of either `astropy.units` or strings that can be converted
to `astropy.units`.
Returns
-------
result : list
A list of the units with their best (i.e., most readable) string version.
"""
return [u.Unit(unit).to_string() for unit in unit_list]
[docs]
def create_spectral_equivalencies_list(spectral_axis_unit,
exclude=[u.jupiterRad, u.earthRad, u.solRad,
u.lyr, u.AU, u.pc, u.Bq, u.micron, u.lsec]):
"""Get all possible conversions from current spectral_axis_unit."""
if spectral_axis_unit in (u.pix, u.dimensionless_unscaled):
return []
# Get unit equivalencies.
try:
curr_spectral_axis_unit_equivalencies = spectral_axis_unit.find_equivalent_units(
equivalencies=u.spectral())
except u.core.UnitConversionError:
return []
# Get local units.
locally_defined_spectral_axis_units = ['Angstrom', 'nm',
'um', 'Hz', 'erg']
local_units = [u.Unit(unit) for unit in locally_defined_spectral_axis_units]
# Remove overlap units.
curr_spectral_axis_unit_equivalencies = list(set(curr_spectral_axis_unit_equivalencies)
- set(local_units + exclude))
# Convert equivalencies into readable versions of the units and sorted alphabetically.
spectral_axis_unit_equivalencies_titles = sorted(units_to_strings(
curr_spectral_axis_unit_equivalencies))
# Concatenate both lists with the local units coming first.
return sorted(units_to_strings(local_units)) + spectral_axis_unit_equivalencies_titles
[docs]
def create_flux_equivalencies_list(flux_unit, spectral_axis_unit):
"""Get all possible conversions for flux from current flux units."""
if ((flux_unit in (u.count, (u.MJy / u.sr), u.dimensionless_unscaled))
or (spectral_axis_unit in (u.pix, u.dimensionless_unscaled))):
return []
# Get unit equivalencies. Value passed into u.spectral_density() is irrelevant.
try:
curr_flux_unit_equivalencies = flux_unit.find_equivalent_units(
equivalencies=u.spectral_density(1 * spectral_axis_unit),
include_prefix_units=False)
except u.core.UnitConversionError:
return []
# Get local units.
locally_defined_flux_units = ['Jy', 'mJy', 'uJy',
'W / (m2 Hz)',
'eV / (s m2 Hz)',
'erg / (s cm2)',
'erg / (s cm2 Angstrom)',
'erg / (s cm2 Hz)',
'ph / (s cm2 Angstrom)',
'ph / (s cm2 Hz)']
local_units = [u.Unit(unit) for unit in locally_defined_flux_units]
# Remove overlap units.
curr_flux_unit_equivalencies = list(set(curr_flux_unit_equivalencies)
- set(local_units))
# Convert equivalencies into readable versions of the units and sort them alphabetically.
flux_unit_equivalencies_titles = sorted(units_to_strings(curr_flux_unit_equivalencies))
# Concatenate both lists with the local units coming first.
return sorted(units_to_strings(local_units)) + flux_unit_equivalencies_titles