CylindricalRepresentation

class astropy.coordinates.CylindricalRepresentation(rho, phi=None, z=None, differentials=None, copy=True)

Bases: BaseRepresentation

Representation of points in 3D cylindrical coordinates.

Parameters:

rhoQuantity

The distance from the z axis to the point(s).

phiQuantity or python:str

The azimuth of the point(s), in angular units, which will be wrapped to an angle between 0 and 360 degrees. This can also be instances of Angle,

zQuantity

The z coordinate(s) of the point(s)

differentialspython:dict, CylindricalDifferential, optional

Any differential classes that should be associated with this representation. The input must either be a single CylindricalDifferential instance, 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.

copybool, optional

If True (default), arrays will be copied. If False, arrays will be references, though possibly broadcast to ensure matching shapes.

Attributes Summary

attr_classes
phi	The azimuth of the point(s).
rho	The distance of the point(s) from the z-axis.
z	The height of the point(s).

Methods Summary

from_cartesian(cart)	Converts 3D rectangular cartesian coordinates to cylindrical polar coordinates.
represent_as(other_class[, differential_class])	Convert coordinates to another representation.
scale_factors()	Scale factors for each component's direction.
to_cartesian()	Converts cylindrical polar coordinates to 3D rectangular cartesian coordinates.
unit_vectors()	Cartesian unit vectors in the direction of each component.

Attributes Documentation

attr_classes = {'phi': <class 'astropy.coordinates.angles.core.Angle'>, 'rho': <class 'astropy.units.quantity.Quantity'>, 'z': <class 'astropy.units.quantity.Quantity'>}

phi

The azimuth of the point(s).

rho

The distance of the point(s) from the z-axis.

z

The height of the point(s).

Methods Documentation

classmethod from_cartesian(cart)

Converts 3D rectangular cartesian coordinates to cylindrical polar coordinates.

represent_as(other_class, differential_class=None)

Convert coordinates to another representation.

If the instance is of the requested class, it is returned unmodified. By default, conversion is done via Cartesian coordinates. Also note that orientation information at the origin is not preserved by conversions through Cartesian coordinates. See the docstring for to_cartesian() for an example.

Parameters:

other_classBaseRepresentation subclass

The type of representation to turn the coordinates into.

differential_classpython:dict of BaseDifferential, optional

Classes in which the differentials should be represented. Can be a single class if only a single differential is attached, otherwise it should be a dict keyed by the same keys as the differentials.

scale_factors()

Scale factors for each component’s direction.

Given unit vectors \(\hat{e}_c\) and scale factors \(f_c\), a change in one component of \(\delta c\) corresponds to a change in representation of \(\delta c \times f_c \times \hat{e}_c\).

Returns:

scale_factorspython:dict of Quantity

The keys are the component names.

to_cartesian()

Converts cylindrical polar coordinates to 3D rectangular cartesian coordinates.

unit_vectors()

Cartesian unit vectors in the direction of each component.

Given unit vectors \(\hat{e}_c\) and scale factors \(f_c\), a change in one component of \(\delta c\) corresponds to a change in representation of \(\delta c \times f_c \times \hat{e}_c\).

Returns:

unit_vectorspython:dict of CartesianRepresentation

The keys are the component names.