gwcs.coordinate_frames.CelestialFrame

class gwcs.coordinate_frames.CelestialFrame(axes_order=None, reference_frame=None, unit=None, axes_names=None, name=None, axis_physical_types=None)

Bases: CoordinateFrame

Representation of a Celesital coordinate system.

This class has a native order of longitude then latitude, meaning axes_names, unit and axis_physical_types should be lon, lat ordered. If your transform is in a different order this should be specified with axes_order.

Parameters:

• axes_order (tuple[int, ...] | None, default: None) – A dimension in the input data that corresponds to this axis.

• reference_frame (AstropyBuiltInFrame | None, default: None) – A reference frame.

• unit (tuple[Unit, ...] | None, default: None) – Units on axes.

• axes_names (tuple[str, ...] | None, default: None) – Names of the axes in this frame.

• name (str | None, default: None) – Name of this frame.

• axis_physical_types (tuple[str | None, ...] | None, default: None) – The UCD 1+ physical types for the axes, in frame order (lon, lat).

Attributes

axes_names	Names of axes in the frame.
axes_order	A tuple of indices which map inputs to axes.
axes_type	Type of this frame, one of 'SPATIAL', 'SPECTRAL', 'TIME'.
axis_physical_types	The axis physical types for this frame.
name	A custom name of this frame.
naxes	The number of axes in this frame.
raw_properties	The raw FrameProperties object for this frame.
reference_frame	Reference frame, used to convert to world coordinate objects.
serialized_classes	This property is used by the low level WCS API in Astropy.
unit	The unit of this frame.
world_axis_object_classes	The APE 14 object classes for this frame.
world_axis_object_components	The APE 14 object components for this frame.

property CelestialFrame.axes_names: tuple[str, ...]

Names of axes in the frame.

property CelestialFrame.axes_order: tuple[int, ...]

A tuple of indices which map inputs to axes.

property CelestialFrame.axes_type: tuple[AxisType | str, ...]

Type of this frame, one of ‘SPATIAL’, ‘SPECTRAL’, ‘TIME’.

property CelestialFrame.axis_physical_types: tuple[str | None, ...]

The axis physical types for this frame.

These physical types are the types in frame order, not transform order.

property CelestialFrame.name: str

A custom name of this frame.

property CelestialFrame.naxes: int

The number of axes in this frame.

property CelestialFrame.raw_properties: FrameProperties

The raw FrameProperties object for this frame.

property CelestialFrame.reference_frame: AstropyBuiltInFrame | None

Reference frame, used to convert to world coordinate objects.

property CelestialFrame.serialized_classes: bool

This property is used by the low level WCS API in Astropy.

By providing it we can duck type as a low level WCS object.

property CelestialFrame.unit: tuple[Unit, ...]

The unit of this frame.

property CelestialFrame.world_axis_object_classes: dict[str, WorldAxisObjectClass]

The APE 14 object classes for this frame.

See also

astropy.wcs.wcsapi.BaseLowLevelWCS.world_axis_object_classes

property CelestialFrame.world_axis_object_components: list[WorldAxisObjectComponent]

The APE 14 object components for this frame.

See also

astropy.wcs.wcsapi.BaseLowLevelWCS.world_axis_object_components

Methods

add_units(arrays)	Add units to the arrays
from_high_level_coordinates(*high_level_coords)	Convert high level coordinate objects to "values" as described by this frame.
is_high_level(*args)	Return True if the input coordinates are already high level objects described by this frame.
remove_units(arrays)	Remove units from the input arrays
to_high_level_coordinates(*values[, correct_1d])	Convert "values" to high level coordinate objects described by this frame.

CelestialFrame.add_units(arrays)

Add units to the arrays

Parameters:

arrays (tuple[LowLevelInput, ...] | LowLevelInput)

Return type:

tuple[LowLevelInput, ...]

CelestialFrame.from_high_level_coordinates(*high_level_coords, correct_1d=True)

Convert high level coordinate objects to “values” as described by this frame.

“values” are the coordinates in array or scalar form, and high level objects are things such as SkyCoord or Quantity. See Shared Python Interface for World Coordinate Systems for details.

Parameters:

high_level_coordinates – One (or more) high level object describing the coordinate.

Returns:

values – naxis number of coordinates as scalars or arrays.

Return type:

numbers.Number or numpy.ndarray

CelestialFrame.is_high_level(*args)

Return True if the input coordinates are already high level objects described by this frame.

This is used by the low level WCS API in Astropy to determine whether to call to_high_level_coordinates or not.

Return type:

bool

CelestialFrame.remove_units(arrays)

Remove units from the input arrays

Parameters:

arrays (tuple[LowLevelInput, ...] | LowLevelInput)

Return type:

tuple[LowLevelArray, ...]

CelestialFrame.to_high_level_coordinates(*values, correct_1d=True)

Convert “values” to high level coordinate objects described by this frame.

“values” are the coordinates in array or scalar form, and high level objects are things such as SkyCoord or Quantity. See Shared Python Interface for World Coordinate Systems for details.

Parameters:

values (numbers.Number, numpy.ndarray, or Quantity) – naxis number of coordinates as scalars or arrays.

Returns:

high_level_coordinates – One (or more) high level object describing the coordinate.

Return type:

object