Converts UVW coordinates between coordinate systems. More...

#include <UVWMachine.h>

Public Member Functions
	UVWMachine (const MDirection::Ref &out, const MDirection &in, Bool EW=False, Bool project=False)
	Constructors have an EW flag, which will give a projection parallel to the polar axis rather than in the direction of the fieldcenter, and a project flag.
	UVWMachine (const MDirection &out, const MDirection &in, Bool EW=False, Bool project=False)
	Construct a UVW conversion machine from the in coordinate and its system to the out coordinate and its system.
	UVWMachine (const MDirection::Ref &out, const MDirection &in, const MeasFrame &frame, Bool EW=False, Bool project=False)
	Construct UVW conversion machine with an explicitly given frame.
	UVWMachine (const MDirection &out, const MDirection &in, const MeasFrame &frame, Bool EW=False, Bool project=False)
	UVWMachine (const UVWMachine &other)
	Copy constructor.
UVWMachine &	operator= (const UVWMachine &other)
	Copy assignments.
	~UVWMachine ()
Vector< Double >	operator() (const Vector< Double > &uv) const
	Return converted UVW coordinates.
Vector< Vector< Double > >	operator() (const Vector< Vector< Double > > &uv) const
MVPosition	operator() (const MVPosition &uv) const
Vector< MVPosition >	operator() (const Vector< MVPosition > &uv) const
const MDirection &	phaseCenter () const
	Return the new phase center coordinates.
Bool	isNOP ()
	Return if the engine is an effective NOP.
const RotMatrix &	rotationUVW () const
	Return a rotation matrix that can be used to convert UVW coordinates: UVW(new) = UVW(old) * rotationUVW()
const MVPosition &	rotationPhase () const
	Return a position vector that can produce the phase correction: dPhase = rotationPhase * UVW(new)
void	convertUVW (Vector< Double > &uv) const
	replace UVW with converted values
void	convertUVW (Vector< Vector< Double > > &uv) const
void	convertUVW (MVPosition &uv) const
void	convertUVW (Vector< MVPosition > &uv) const
Double	getPhase (Vector< Double > &uv) const
	Get phase shift (in implied units of UVW), and change input uvw as well.
Vector< Double >	getPhase (Vector< Vector< Double > > &uv) const
Double	getPhase (MVPosition &uv) const
Vector< Double >	getPhase (Vector< MVPosition > &uv) const
void	convertUVW (Double &phase, Vector< Double > &uv) const
	Replace UVW with converted, and return phase.
void	convertUVW (Vector< Double > &phase, Vector< Vector< Double > > &uv) const
void	convertUVW (Double &phase, MVPosition &uv) const
void	convertUVW (Vector< Double > &phase, Vector< MVPosition > &uv) const
void	reCalculate ()
	Recalculate the parameters for the machine after e.g.
Private Member Functions
	UVWMachine ()
	default constructor: not implemented
void	init ()
	Initialise machinery.
void	planetinit ()
	Planet handling.
void	copy (const UVWMachine &other)
	Copy data members.
Private Attributes
Bool	ew_p
	EW flag.
Bool	proj_p
	Projection flag.
Bool	zp_p
	Zero phase flag (for speed)
Bool	nop_p
	No conversion necessary flag.
MDirection	in_p
	Old phase center.
MDirection::Ref	outref_p
	New coordinate reference.
MDirection	outin_p
	Old phase center in new coordinates.
MDirection	out_p
	New phase center.
RotMatrix	rot1_p
	Rotation Matrix to go from input UVW to coordinate system.
RotMatrix	rot2_p
	Rotation matrix to go from old system to new system.
RotMatrix	rot3_p
	Rotation Matrix to go from new coordinate system to output UVW.
RotMatrix	rot4_p
	Rotation Matrix to project UV-plane onto.
RotMatrix	uvrot_p
	UVW rotation.
RotMatrix	uvproj_p
	UVW rotation including projection.
MVPosition	phrot_p
	Phase rotation.
MDirection::Convert	conv_p
	Conversion engine.

Detailed Description

Converts UVW coordinates between coordinate systems.

Intended use:

Public interface

 <h3>Review Status</h3><dl><dt>Reviewed By:<dd>UNKNOWN<dt>Date Reviewed:<dd>before2004/08/25<dt>Test programs:<dd>tUVWMachine</dl>

Prerequisite

MDirection class

Etymology

From UVW coordinates and machinery

Synopsis

The construction of a UVWMachine class object creates a machine that can convert UVW coordinates from one coordinate system to another. In addition it can also supply the phase rotation necessary to move to a new position.

The constructors need an input MDirection to specify the input UVW coordinates reference direction and coordinate system. An EW flag can be specified to indicate the different type of UVW coordinates. I.e. projection along polar axis rather than towards observing direction (not implemented yet). A project flag, if set, will re-project the resulting UV plane onto the in-direction reference plane.

The constructors also need an output coordinate system ( MDirection::Ref ) or an output MDirection (including the reference coordinate system). The first case indicates that the real position on the sky does not change (only the coordinate system used); the second indicates that the UVW should be for a new position on the sky (in addition to maybe a different coordinate system). In the first case only the UVW coordinates will change, in the second the UVW positions will change, but also the phase of the observed data will have to change. For some conversions a reference frame is needed (to indicate e.g. the position or time). This frame can be part of one of the constructor references, but can also be specified separately in the constructor. A change in the frame parameter can be made outside the UVWMachine by e.g. frame.reset(anMEpoch).
Caution: If the frame is changed by the user of the conversion machine, the machine has to be reinitialised before using it for output by using reCalculate();

Projection entails a rotation; For changes to a fixed frame (i;e; not changing with e;g; time), the rotation matrix is calculated only once; In other cases it has to be calculated per series of uvw conversions; The latter case can hence be time consuming;

Tip: If either the input or output direction/reference specifies a planet, action is special; Planets are assumed to be in J2000 positions, since that is the only way to carry them from conversion to conversion (and also have a variable phase-center; which can, btw, always be obtained by the phaseCenter() member);
Note that a reCalculate() is necessary between calls of the engine, since the planetary position will change from time to time (i.e. with the Frame).

If no explicit output coordinate is given (i.e. no phase shift necessary), and the conversion from input to output is an essential NOP, and no reprojection to the input plane is required, the machine will bypass all calculations. This state can be inspected by the isNOP() method.

If you want to convert to say an azimuth/elevation map of the Sun, this can be done to have either two conversion engines (original to Sun, then Sun to AzEl), or by conversion of the Sun to AzEl before entering the engine.
Tip: The output of the machine is either a set of rotation matrices that can be used to convert UVW coordinates (and, if necessary, phases); or the UVW conversion and actual phase can be calculated from a given UVW coordinate (or set of coordinates);

Tip: Since e;g; in an EW interferometer (or any set of baselines on a line) the phase correction and UVW transform scales with the length of the baseline, conversion of a nominal (say 1m) baseline suffices to easily calculate others; The same is true for baselines in a plane, where a conversion of two orthogonal baselines in that plane will suffice;

Example

        // Given a current phase stopping Center
        MDirection indir(Quantity(3.25745692, "rad"),
                         Quantity(0.040643336,"rad"),
                         MDirection::Ref(MDirection::B1950));
        // Conversion to J2000 is set by:
        UVWMachine uvm(MDirection::Ref(MDirection::J2000), indir);
        // The rotation matrix to go to new UVW is obtained by:
        RotMatrix rm(uvm.rotationUVM());
        // If an UVW specified:
        MVPosition uvw(-739.048461, -1939.10604, 1168.62562);
        // This can be converted by e.g.:
        uvw *= rm;
        // Or, alternatively, by e.g.:
        uvm.convertUVW(uvw);

Motivation

To aid making maps in different coordinate systems

To Do

add EW UVW coordinates
check if non right-handed coordinates systems (like AzEl) are handled correctly
provide a MVuvw and Muvw class to cater for second order effects appropiately

Definition at line 160 of file UVWMachine.h.

Constructor & Destructor Documentation

casa::UVWMachine::UVWMachine	(	const MDirection::Ref &	out,
		const MDirection &	in,
		Bool	EW = `False`,
		Bool	project = `False`
	)

Constructors have an EW flag, which will give a projection parallel to the polar axis rather than in the direction of the fieldcenter, and a project flag.

The last will correct the UV coordinates to re-project them onto the plane specified by the in direction

Construct a UVW conversion machine from the in coordinate and its system to the out coordinate system (output absolute direction remains the same)

casa::UVWMachine::UVWMachine	(	const MDirection &	out,
		const MDirection &	in,
		Bool	EW = `False`,
		Bool	project = `False`
	)

Construct a UVW conversion machine from the in coordinate and its system to the out coordinate and its system.

casa::UVWMachine::UVWMachine	(	const MDirection::Ref &	out,
		const MDirection &	in,
		const MeasFrame &	frame,
		Bool	EW = `False`,
		Bool	project = `False`
	)

Construct UVW conversion machine with an explicitly given frame.

casa::UVWMachine::UVWMachine	(	const MDirection &	out,
		const MDirection &	in,
		const MeasFrame &	frame,
		Bool	EW = `False`,
		Bool	project = `False`
	)

casa::UVWMachine::UVWMachine ( const UVWMachine & other )

Copy constructor.

casa::UVWMachine::~UVWMachine ( )

casa::UVWMachine::UVWMachine ( ) [private]

default constructor: not implemented

Member Function Documentation

void casa::UVWMachine::convertUVW ( Vector< Double > & uv ) const

replace UVW with converted values

void casa::UVWMachine::convertUVW ( Vector< Vector< Double > > & uv ) const

void casa::UVWMachine::convertUVW ( MVPosition & uv ) const

void casa::UVWMachine::convertUVW ( Vector< MVPosition > & uv ) const

void casa::UVWMachine::convertUVW	(	Double &	phase,
		Vector< Double > &	uv
	)		const

Replace UVW with converted, and return phase.

void casa::UVWMachine::convertUVW	(	Vector< Double > &	phase,
		Vector< Vector< Double > > &	uv
	)		const

void casa::UVWMachine::convertUVW	(	Double &	phase,
		MVPosition &	uv
	)		const

void casa::UVWMachine::convertUVW	(	Vector< Double > &	phase,
		Vector< MVPosition > &	uv
	)		const

void casa::UVWMachine::copy ( const UVWMachine & other ) [private]

Copy data members.

Double casa::UVWMachine::getPhase ( Vector< Double > & uv ) const

Get phase shift (in implied units of UVW), and change input uvw as well.

Vector<Double> casa::UVWMachine::getPhase ( Vector< Vector< Double > > & uv ) const

Double casa::UVWMachine::getPhase ( MVPosition & uv ) const

Vector<Double> casa::UVWMachine::getPhase ( Vector< MVPosition > & uv ) const

void casa::UVWMachine::init ( ) [private]

Initialise machinery.

Bool casa::UVWMachine::isNOP ( ) [inline]

Return if the engine is an effective NOP.

Definition at line 206 of file UVWMachine.h.

References nop_p.

Vector<Double> casa::UVWMachine::operator() ( const Vector< Double > & uv ) const

Return converted UVW coordinates.

Vector<Vector<Double> > casa::UVWMachine::operator() ( const Vector< Vector< Double > > & uv ) const

MVPosition casa::UVWMachine::operator() ( const MVPosition & uv ) const

Vector<MVPosition > casa::UVWMachine::operator() ( const Vector< MVPosition > & uv ) const

UVWMachine& casa::UVWMachine::operator= ( const UVWMachine & other )

Copy assignments.

const MDirection& casa::UVWMachine::phaseCenter ( ) const

Return the new phase center coordinates.

void casa::UVWMachine::planetinit ( ) [private]

Planet handling.

void casa::UVWMachine::reCalculate ( )

Recalculate the parameters for the machine after e.g.

a frame change

const MVPosition& casa::UVWMachine::rotationPhase ( ) const

Return a position vector that can produce the phase correction: dPhase = rotationPhase * UVW(new)

const RotMatrix& casa::UVWMachine::rotationUVW ( ) const

Return a rotation matrix that can be used to convert UVW coordinates: UVW(new) = UVW(old) * rotationUVW()

Member Data Documentation

MDirection::Convert casa::UVWMachine::conv_p [private]

Conversion engine.

Definition at line 272 of file UVWMachine.h.

Bool casa::UVWMachine::ew_p [private]

EW flag.

Definition at line 242 of file UVWMachine.h.

MDirection casa::UVWMachine::in_p [private]

Old phase center.

Definition at line 250 of file UVWMachine.h.

Bool casa::UVWMachine::nop_p [private]

No conversion necessary flag.

Definition at line 248 of file UVWMachine.h.

Referenced by isNOP().

MDirection casa::UVWMachine::out_p [private]

New phase center.

Definition at line 256 of file UVWMachine.h.

MDirection casa::UVWMachine::outin_p [private]

Old phase center in new coordinates.

Definition at line 254 of file UVWMachine.h.

MDirection::Ref casa::UVWMachine::outref_p [private]

New coordinate reference.

Definition at line 252 of file UVWMachine.h.

MVPosition casa::UVWMachine::phrot_p [private]

Phase rotation.

Definition at line 270 of file UVWMachine.h.

Bool casa::UVWMachine::proj_p [private]

Projection flag.

Definition at line 244 of file UVWMachine.h.

RotMatrix casa::UVWMachine::rot1_p [private]

Rotation Matrix to go from input UVW to coordinate system.

Definition at line 258 of file UVWMachine.h.

RotMatrix casa::UVWMachine::rot2_p [private]

Rotation matrix to go from old system to new system.

Definition at line 260 of file UVWMachine.h.

RotMatrix casa::UVWMachine::rot3_p [private]

Rotation Matrix to go from new coordinate system to output UVW.

Definition at line 262 of file UVWMachine.h.

RotMatrix casa::UVWMachine::rot4_p [private]

Rotation Matrix to project UV-plane onto.

Definition at line 264 of file UVWMachine.h.

RotMatrix casa::UVWMachine::uvproj_p [private]

UVW rotation including projection.

Definition at line 268 of file UVWMachine.h.

RotMatrix casa::UVWMachine::uvrot_p [private]

UVW rotation.

Definition at line 266 of file UVWMachine.h.

Bool casa::UVWMachine::zp_p [private]

Zero phase flag (for speed)

Definition at line 246 of file UVWMachine.h.

The documentation for this class was generated from the following file:

casacore/measures/Measures/UVWMachine.h

Public Member Functions

Private Member Functions

Private Attributes