Bases: object
Abstract superclass for all coordinate classes representing points in three dimensions.
Notes
Subclasses must implement __init__, and define the latangle and lonangle properties. They may also override the equinox property, or leave it unaltered to indicate the coordinates are equinoxless.
_initialize_latlon is provided to implement typical initialization features, and should be called from a subclass’ __init__. See the classes in astropy.coordinates.builtin_systems for examples of this.
Attributes Summary
cartesian | |
distance | The radial distance for this coordinate object as an Distance object. |
equinox | The equinox of this system, or None to indicate no equinox specified. |
isscalar | True if this coordinate contains scalar angles/distances, or False if |
latangle | The latitudinal/elevation angle for these coordinates as an Angle object. |
lonangle | The longitudinal/azimuthal angle for these coordinates as an Angle object. |
x | |
y | |
z |
Methods Summary
from_name(name) | Given a name, query the CDS name resolver to attempt to retrieve coordinate information for that object. |
is_transformable_to(tosys) | Determines if this coordinate can be transformed to a particular system. |
match_to_catalog_3d(catalogcoord[, nthneighbor]) | Finds the nearest 3-dimensional matches of this coordinate to a set of catalog coordinates. |
match_to_catalog_sky(catalogcoord[, nthneighbor]) | Finds the nearest on-sky matches of this coordinate in a set of catalog coordinates. |
separation(other) | Computes on-sky separation between this coordinate and another. |
separation_3d(other) | Computes three dimensional separation between this coordinate and another. |
to_string([style]) | A string representation of the coordinates. |
transform_to(tosys) | Transform this coordinate to a new system. |
Attributes Documentation
The radial distance for this coordinate object as an Distance object.
If set as a tuple, the tuple will be passed into the Distance constructor.
Alternatively, this may be None, indicating an unknown/not given distance. Where necessary, this object will be interpreted as angles on the unit sphere.
True if this coordinate contains scalar angles/distances, or False if they are array-like
The latitudinal/elevation angle for these coordinates as an Angle object.
Subclasses will often provide properties returning the same object, but with a name more appropriate for the particular subclass.
The longitudinal/azimuthal angle for these coordinates as an Angle object.
Subclasses will often provide properties returning the same object, but with a name more appropriate for the particular subclass.
Methods Documentation
Given a name, query the CDS name resolver to attempt to retrieve coordinate information for that object. The search database, sesame url, and query timeout can be set through configuration items in astropy.coordinates.name_resolve – see docstring for astropy.coordinates.name_resolve.get_icrs_coordinates for more information.
Parameters: | name : str
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Returns: | coord : SphericalCoordinatesBase
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Determines if this coordinate can be transformed to a particular system.
Parameters: | tosys : class
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Returns: | transformable : bool or str
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Finds the nearest 3-dimensional matches of this coordinate to a set of catalog coordinates.
This finds the 3-dimensional closest neighbor, which is only different from the on-sky distance if distance is set in this object or the catalogcoord object.
Parameters: | catalogcoord : SphericalCoordinatesBase
nthneighbor : int, optional
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Returns: | idx : integer array
sep2d : Angle
dist3d : Quantity
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Notes
This method requires scipy to be installed or it will fail.
Finds the nearest on-sky matches of this coordinate in a set of catalog coordinates.
Parameters: | catalogcoord : SphericalCoordinatesBase
nthneighbor : int, optional
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Returns: | idx : integer array
sep2d : Angle
dist3d : Quantity
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Notes
This method requires scipy to be installed or it will fail.
Computes on-sky separation between this coordinate and another.
Parameters: | other : SphericalCoordinatesBase
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Returns: | sep : Angle
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Notes
The separation is calculated using the Vincenty formula, which is stable at all locations, including poles and antipodes [R2].
[R2] | http://en.wikipedia.org/wiki/Great-circle_distance |
Computes three dimensional separation between this coordinate and another.
Parameters: | other : SphericalCoordinatesBase
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Returns: | sep : Distance
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Raises: | ValueError :
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A string representation of the coordinates.
See astropy.coordinates.Angle.to_string() for details and keyword arguments (the two angles forming the coordinates are are both astropy.coordinates.Angle instances). Keyword arguments are passed to astropy.coordinates.Angle.to_string().
Parameters: | style : {‘hmsdms’, ‘dms’, ‘decimal’, None}
kwargs :
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Transform this coordinate to a new system.
Parameters: | tosys : class
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Returns: | transcoord :
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Raises: | ValueError :
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