CylindricalRepresentation

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

Bases: astropy.coordinates.BaseRepresentation

Representation of points in 3D cylindrical coordinates.

Parameters:

rho : Quantity

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

phi : Quantity or 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,

z : Quantity

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

differentials : 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.

copy : bool, optional

If True (default), arrays will be copied rather than referenced.

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.
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.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.

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_factors : 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_vectors : dict of CartesianRepresentation

The keys are the component names.