GlobalSinusoidalProjection

class sofia_redux.scan.coordinate_systems.projection.global_sinusoidal_projection.GlobalSinusoidalProjection

Bases: SphericalProjection

Initialize a global sinusoidal projection.

The global spherical projection is a very simple projection that converts between coordinates and offsets when the projection is also in spherical coordinates and celestial and native poles are equivalent. I.e, the only parameter of importance is the reference position of the projection.

Methods Summary

deproject(projected[, coordinates])	Deproject global sinusoidal projection offsets to coordinates.
get_fits_id()	Return the FITS ID for the projection.
get_full_name()	Return the full name of the projection.
get_offsets(theta, phi[, offsets])	Get the offsets given theta and phi.
get_phi_theta(offset[, phi_theta])	Return the phi_theta coordinates.
project(coordinates[, projected])	Project the coordinates.

Methods Documentation

deproject(projected, coordinates=None)

Deproject global sinusoidal projection offsets to coordinates.

The reverse projection (deprojection) is used to convert offsets in relation to a reference position into spherical coordinates as follows:

y = y_reference + dy x = x_reference + (dx / cos(y))

Parameters:

projectedCoordinate2D

The projected coordinates to deproject.

coordinatesSphericalCoordinates, optional

The output deprojected coordinates. Will be created if not supplied.

Returns:

coordinatesCoordinate2D

The deprojected coordinates.

classmethod get_fits_id()

Return the FITS ID for the projection.

Returns:

str

classmethod get_full_name()

Return the full name of the projection.

Returns:

str

get_offsets(theta, phi, offsets=None)

Get the offsets given theta and phi.

Parameters:

thetaunits.Quantity

The theta angle.

phiunits.Quantity

The phi angle.

offsetsCoordinate2D, optional

An optional coordinate system in which to place the results.

Returns:

offsetsCoordinate2D

get_phi_theta(offset, phi_theta=None)

Return the phi_theta coordinates.

Parameters:

offsetCoordinate2D

phi_thetaSphericalCoordinates, optional

An optional output coordinate system in which to place the results.

Returns:

coordinatesSphericalCoordinates

project(coordinates, projected=None)

Project the coordinates.

The forward projection for the global sinusoidal projection converts spherical coordinates to cartesian offsets from a reference position as follows:

dx = (x - x_reference) * cos(y) dy = y - y_reference

Parameters:

coordinatesSphericalCoordinates

The coordinates to project.

projectedCoordinate2D, optional

The output coordinates. Will be created if not supplied.

Returns:

projectedCoordinate2D

The projected coordinates.