RadialRepresentation¶
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class
astropy.coordinates.
RadialRepresentation
(distance, differentials=None, copy=True)[source] [edit on github]¶ Bases:
astropy.coordinates.BaseRepresentation
Representation of the distance of points from the origin.
Note that this is mostly intended as an internal helper representation. It can do little else but being used as a scale in multiplication.
Parameters: distance :
Quantity
The distance of the point(s) from the origin.
differentials : dict,
BaseDifferential
, optionalAny differential classes that should be associated with this representation. The input must either be a single
BaseDifferential
instance (see_compatible_differentials
for valid types), or a dictionary of of differential instances with keys set to a string representation of the SI unit with which the differential (derivative) is taken. For example, for a velocity differential on a positional representation, the key would be's'
for seconds, indicating that the derivative is a time derivative.copy : bool, optional
If
True
(default), arrays will be copied rather than referenced.Attributes Summary
attr_classes
distance
The distance from the origin to the point(s). Methods Summary
from_cartesian
(cart)Converts 3D rectangular cartesian coordinates to radial coordinate. norm
()Vector norm. scale_factors
()Scale factors for each component’s direction. to_cartesian
()Cannot convert radial representation to cartesian. unit_vectors
()Cartesian unit vectors are undefined for radial representation. Attributes Documentation
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attr_classes
= OrderedDict([('distance', <class 'astropy.units.quantity.Quantity'>)])¶
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distance
¶ The distance from the origin to the point(s).
Methods Documentation
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classmethod
from_cartesian
(cart)[source] [edit on github]¶ Converts 3D rectangular cartesian coordinates to radial coordinate.
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norm
()[source] [edit on github]¶ Vector norm.
Just the distance itself.
Returns: norm :
Quantity
Dimensionless ones, with the same shape as the representation.
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scale_factors
()[source] [edit on github]¶ Scale factors for each component’s direction.
Given unit vectors
and scale factors
, a change in one component of
corresponds to a change in representation of
.
Returns: scale_factors : dict of
Quantity
The keys are the component names.
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to_cartesian
()[source] [edit on github]¶ Cannot convert radial representation to cartesian.
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unit_vectors
()[source] [edit on github]¶ Cartesian unit vectors are undefined for radial representation.
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