Skip to content

Commit

Permalink
Merge 69d71aa into 5d4c3fb
Browse files Browse the repository at this point in the history
  • Loading branch information
@nmearl
nmearl committed Jul 31, 2019
2 parents 5d4c3fb + 69d71aa commit 43e98a0
Show file tree
Hide file tree
Showing 2 changed files with 107 additions and 106 deletions.
5 changes: 2 additions & 3 deletions specutils/spectra/spectrum1d.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,14 +6,14 @@
from astropy.utils.decorators import lazyproperty
from astropy.nddata import NDUncertainty
from ..wcs import WCSWrapper, WCSAdapter
from .spectrum_mixin import OneDSpectrumMixin
from .spectrum_mixin import SpectralDataMixin, SpectralAxisMixin

__all__ = ['Spectrum1D']

__doctest_skip__ = ['Spectrum1D.spectral_resolution']


class Spectrum1D(OneDSpectrumMixin, NDDataRef):
class Spectrum1D(SpectralAxisMixin, SpectralDataMixin, NDDataRef):
"""
Spectrum container for 1D spectral data.
Expand Down Expand Up @@ -272,7 +272,6 @@ def __repr__(self):

return result


def spectral_resolution(self, true_dispersion, delta_dispersion, axis=-1):
"""Evaluate the probability distribution of the spectral resolution.
Expand Down
208 changes: 105 additions & 103 deletions specutils/spectra/spectrum_mixin.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
__all__ = ['OneDSpectrumMixin']


class OneDSpectrumMixin:
class SpectralAxisMixin:
@property
def _spectral_axis_numpy_index(self):
return self.data.ndim - 1 - self.wcs.wcs.spec
Expand Down Expand Up @@ -80,6 +80,110 @@ def spectral_axis_unit(self):
"""
return self.wcs.spectral_axis_unit

def with_spectral_unit(self, unit, velocity_convention=None,
rest_value=None):
"""
Returns a new spectrum with a different spectral axis unit.
Parameters
----------
unit : :class:`~astropy.units.Unit`
Any valid spectral unit: velocity, (wave)length, or frequency.
Only vacuum units are supported.
velocity_convention : 'relativistic', 'radio', or 'optical'
The velocity convention to use for the output velocity axis.
Required if the output type is velocity. This can be either one
of the above strings, or an `astropy.units` equivalency.
rest_value : :class:`~astropy.units.Quantity`
A rest wavelength or frequency with appropriate units. Required if
output type is velocity. The spectrum's WCS should include this
already if the *input* type is velocity, but the WCS's rest
wavelength/frequency can be overridden with this parameter.
.. note: This must be the rest frequency/wavelength *in vacuum*,
even if your spectrum has air wavelength units
"""
new_wcs, new_meta = self._new_spectral_wcs(
unit=unit,
velocity_convention=velocity_convention or self._velocity_convention,
rest_value=rest_value or self.rest_value)

spectrum = self.__class__(flux=self.flux, wcs=new_wcs, meta=new_meta)

return spectrum

def _new_wcs_argument_validation(self, unit, velocity_convention,
rest_value):
# Allow string specification of units, for example
if not isinstance(unit, u.UnitBase):
unit = u.Unit(unit)

# Velocity conventions: required for frq <-> velo
# convert_spectral_axis will handle the case of no velocity
# convention specified & one is required
if velocity_convention in DOPPLER_CONVENTIONS:
velocity_convention = DOPPLER_CONVENTIONS[velocity_convention]
elif (velocity_convention is not None and
velocity_convention not in DOPPLER_CONVENTIONS.values()):
raise ValueError("Velocity convention must be radio, optical, "
"or relativistic.")

# If rest value is specified, it must be a quantity
if (rest_value is not None and
(not hasattr(rest_value, 'unit') or
not rest_value.unit.is_equivalent(u.m, u.spectral()))):
raise ValueError("Rest value must be specified as an astropy "
"quantity with spectral equivalence.")

return unit

def _new_spectral_wcs(self, unit, velocity_convention=None,
rest_value=None):
"""
Returns a new WCS with a different Spectral Axis unit.
Parameters
----------
unit : :class:`~astropy.units.Unit`
Any valid spectral unit: velocity, (wave)length, or frequency.
Only vacuum units are supported.
velocity_convention : 'relativistic', 'radio', or 'optical'
The velocity convention to use for the output velocity axis.
Required if the output type is velocity. This can be either one
of the above strings, or an `astropy.units` equivalency.
rest_value : :class:`~astropy.units.Quantity`
A rest wavelength or frequency with appropriate units. Required if
output type is velocity. The cube's WCS should include this
already if the *input* type is velocity, but the WCS's rest
wavelength/frequency can be overridden with this parameter.
.. note: This must be the rest frequency/wavelength *in vacuum*,
even if your cube has air wavelength units
"""

unit = self._new_wcs_argument_validation(unit, velocity_convention,
rest_value)

if velocity_convention is not None:
equiv = getattr(u, 'doppler_{0}'.format(velocity_convention))
rest_value.to(unit, equivalencies=equiv)

# Store the original unit information for posterity
meta = self._meta.copy()

if 'original_unit' not in self._meta:
meta['original_unit'] = self.wcs.spectral_axis_unit

# Create the new wcs object
new_wcs = self.wcs.with_spectral_unit(unit=unit,
rest_value=rest_value,
velocity_convention=velocity_convention)

return new_wcs, meta


class SpectralDataMixin:
@property
def flux(self):
"""
Expand Down Expand Up @@ -187,108 +291,6 @@ def velocity(self):

return new_data

def with_spectral_unit(self, unit, velocity_convention=None,
rest_value=None):
"""
Returns a new spectrum with a different spectral axis unit.
Parameters
----------
unit : :class:`~astropy.units.Unit`
Any valid spectral unit: velocity, (wave)length, or frequency.
Only vacuum units are supported.
velocity_convention : 'relativistic', 'radio', or 'optical'
The velocity convention to use for the output velocity axis.
Required if the output type is velocity. This can be either one
of the above strings, or an `astropy.units` equivalency.
rest_value : :class:`~astropy.units.Quantity`
A rest wavelength or frequency with appropriate units. Required if
output type is velocity. The spectrum's WCS should include this
already if the *input* type is velocity, but the WCS's rest
wavelength/frequency can be overridden with this parameter.
.. note: This must be the rest frequency/wavelength *in vacuum*,
even if your spectrum has air wavelength units
"""
new_wcs, new_meta = self._new_spectral_wcs(
unit=unit,
velocity_convention=velocity_convention or self._velocity_convention,
rest_value=rest_value or self.rest_value)

spectrum = self.__class__(flux=self.flux, wcs=new_wcs, meta=new_meta)

return spectrum

def _new_wcs_argument_validation(self, unit, velocity_convention,
rest_value):
# Allow string specification of units, for example
if not isinstance(unit, u.UnitBase):
unit = u.Unit(unit)

# Velocity conventions: required for frq <-> velo
# convert_spectral_axis will handle the case of no velocity
# convention specified & one is required
if velocity_convention in DOPPLER_CONVENTIONS:
velocity_convention = DOPPLER_CONVENTIONS[velocity_convention]
elif (velocity_convention is not None and
velocity_convention not in DOPPLER_CONVENTIONS.values()):
raise ValueError("Velocity convention must be radio, optical, "
"or relativistic.")

# If rest value is specified, it must be a quantity
if (rest_value is not None and
(not hasattr(rest_value, 'unit') or
not rest_value.unit.is_equivalent(u.m, u.spectral()))):
raise ValueError("Rest value must be specified as an astropy "
"quantity with spectral equivalence.")

return unit

def _new_spectral_wcs(self, unit, velocity_convention=None,
rest_value=None):
"""
Returns a new WCS with a different Spectral Axis unit.
Parameters
----------
unit : :class:`~astropy.units.Unit`
Any valid spectral unit: velocity, (wave)length, or frequency.
Only vacuum units are supported.
velocity_convention : 'relativistic', 'radio', or 'optical'
The velocity convention to use for the output velocity axis.
Required if the output type is velocity. This can be either one
of the above strings, or an `astropy.units` equivalency.
rest_value : :class:`~astropy.units.Quantity`
A rest wavelength or frequency with appropriate units. Required if
output type is velocity. The cube's WCS should include this
already if the *input* type is velocity, but the WCS's rest
wavelength/frequency can be overridden with this parameter.
.. note: This must be the rest frequency/wavelength *in vacuum*,
even if your cube has air wavelength units
"""

unit = self._new_wcs_argument_validation(unit, velocity_convention,
rest_value)

if velocity_convention is not None:
equiv = getattr(u, 'doppler_{0}'.format(velocity_convention))
rest_value.to(unit, equivalencies=equiv)

# Store the original unit information for posterity
meta = self._meta.copy()

if 'original_unit' not in self._meta:
meta['original_unit'] = self.wcs.spectral_axis_unit

# Create the new wcs object
new_wcs = self.wcs.with_spectral_unit(unit=unit,
rest_value=rest_value,
velocity_convention=velocity_convention)

return new_wcs, meta


class InplaceModificationMixin:
# Example methods follow to demonstrate how methods can be written to be
Expand Down

0 comments on commit 43e98a0

Please sign in to comment.