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casacore::UVWMachine Class Reference

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. More...
 
 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. More...
 
 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. More...
 
 UVWMachine (const MDirection &out, const MDirection &in, const MeasFrame &frame, Bool EW=False, Bool project=False)
 
 UVWMachine (const UVWMachine &other)
 Copy constructor. More...
 
UVWMachineoperator= (const UVWMachine &other)
 Copy assignments. More...
 
 ~UVWMachine ()
 
Vector< Doubleoperator() (const Vector< Double > &uv) const
 Return converted UVW coordinates. More...
 
Vector< Vector< Double > > operator() (const Vector< Vector< Double > > &uv) const
 
MVPosition operator() (const MVPosition &uv) const
 
Vector< MVPositionoperator() (const Vector< MVPosition > &uv) const
 
const MDirectionphaseCenter () const
 Return the new phase center coordinates. More...
 
Bool isNOP ()
 Return if the engine is an effective NOP. More...
 
const RotMatrixrotationUVW () const
 Return a rotation matrix that can be used to convert UVW coordinates: UVW(new) = UVW(old) * rotationUVW() More...
 
const MVPositionrotationPhase () const
 Return a position vector that can produce the phase correction: dPhase = rotationPhase * UVW(new) More...
 
void convertUVW (Vector< Double > &uv) const
 replace UVW with converted values More...
 
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. More...
 
Vector< DoublegetPhase (Vector< Vector< Double > > &uv) const
 
Double getPhase (MVPosition &uv) const
 
Vector< DoublegetPhase (Vector< MVPosition > &uv) const
 
void convertUVW (Double &phase, Vector< Double > &uv) const
 Replace UVW with converted, and return phase. More...
 
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. More...
 

Private Member Functions

 UVWMachine ()
 default constructor: not implemented More...
 
void init ()
 Initialise machinery. More...
 
void planetinit ()
 Planet handling. More...
 
void copy (const UVWMachine &other)
 Copy data members. More...
 

Private Attributes

Bool ew_p
 EW flag. More...
 
Bool proj_p
 Projection flag. More...
 
Bool zp_p
 Zero phase flag (for speed) More...
 
Bool nop_p
 No conversion necessary flag. More...
 
MDirection in_p
 Old phase center. More...
 
MDirection::Ref outref_p
 New coordinate reference. More...
 
MDirection outin_p
 Old phase center in new coordinates. More...
 
MDirection out_p
 New phase center. More...
 
RotMatrix rot1_p
 Rotation Matrix to go from input UVW to coordinate system. More...
 
RotMatrix rot2_p
 Rotation matrix to go from old system to new system. More...
 
RotMatrix rot3_p
 Rotation Matrix to go from new coordinate system to output UVW. More...
 
RotMatrix rot4_p
 Rotation Matrix to project UV-plane onto. More...
 
RotMatrix uvrot_p
 UVW rotation. More...
 
RotMatrix uvproj_p
 UVW rotation including projection. More...
 
MVPosition phrot_p
 Phase rotation. More...
 
MDirection::Convert conv_p
 Conversion engine. More...
 

Detailed Description

Converts UVW coordinates between coordinate systems.

Intended use:

Public interface

Review Status

Reviewed By:
UNKNOWN
Date Reviewed:
before2004/08/25
Test programs:
tUVWMachine

Prerequisite

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"),
// Conversion to J2000 is set by:
// 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

Definition at line 160 of file UVWMachine.h.

Constructor & Destructor Documentation

casacore::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)

casacore::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.

casacore::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.

casacore::UVWMachine::UVWMachine ( const MDirection out,
const MDirection in,
const MeasFrame frame,
Bool  EW = False,
Bool  project = False 
)
casacore::UVWMachine::UVWMachine ( const UVWMachine other)

Copy constructor.

casacore::UVWMachine::~UVWMachine ( )
casacore::UVWMachine::UVWMachine ( )
private

default constructor: not implemented

Member Function Documentation

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

replace UVW with converted values

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

Replace UVW with converted, and return phase.

void casacore::UVWMachine::convertUVW ( Vector< Double > &  phase,
Vector< Vector< Double > > &  uv 
) const
void casacore::UVWMachine::convertUVW ( Double phase,
MVPosition uv 
) const
void casacore::UVWMachine::convertUVW ( Vector< Double > &  phase,
Vector< MVPosition > &  uv 
) const
void casacore::UVWMachine::copy ( const UVWMachine other)
private

Copy data members.

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

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

Vector<Double> casacore::UVWMachine::getPhase ( Vector< Vector< Double > > &  uv) const
Double casacore::UVWMachine::getPhase ( MVPosition uv) const
Vector<Double> casacore::UVWMachine::getPhase ( Vector< MVPosition > &  uv) const
void casacore::UVWMachine::init ( )
private

Initialise machinery.

Bool casacore::UVWMachine::isNOP ( )
inline

Return if the engine is an effective NOP.

Definition at line 206 of file UVWMachine.h.

References nop_p.

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

Return converted UVW coordinates.

Vector<Vector<Double> > casacore::UVWMachine::operator() ( const Vector< Vector< Double > > &  uv) const
MVPosition casacore::UVWMachine::operator() ( const MVPosition uv) const
Vector<MVPosition > casacore::UVWMachine::operator() ( const Vector< MVPosition > &  uv) const
UVWMachine& casacore::UVWMachine::operator= ( const UVWMachine other)

Copy assignments.

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

Return the new phase center coordinates.

void casacore::UVWMachine::planetinit ( )
private

Planet handling.

void casacore::UVWMachine::reCalculate ( )

Recalculate the parameters for the machine after e.g.

a frame change

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

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

const RotMatrix& casacore::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 casacore::UVWMachine::conv_p
private

Conversion engine.

Definition at line 272 of file UVWMachine.h.

Bool casacore::UVWMachine::ew_p
private

EW flag.

Definition at line 242 of file UVWMachine.h.

MDirection casacore::UVWMachine::in_p
private

Old phase center.

Definition at line 250 of file UVWMachine.h.

Bool casacore::UVWMachine::nop_p
private

No conversion necessary flag.

Definition at line 248 of file UVWMachine.h.

Referenced by isNOP().

MDirection casacore::UVWMachine::out_p
private

New phase center.

Definition at line 256 of file UVWMachine.h.

MDirection casacore::UVWMachine::outin_p
private

Old phase center in new coordinates.

Definition at line 254 of file UVWMachine.h.

MDirection::Ref casacore::UVWMachine::outref_p
private

New coordinate reference.

Definition at line 252 of file UVWMachine.h.

MVPosition casacore::UVWMachine::phrot_p
private

Phase rotation.

Definition at line 270 of file UVWMachine.h.

Bool casacore::UVWMachine::proj_p
private

Projection flag.

Definition at line 244 of file UVWMachine.h.

RotMatrix casacore::UVWMachine::rot1_p
private

Rotation Matrix to go from input UVW to coordinate system.

Definition at line 258 of file UVWMachine.h.

RotMatrix casacore::UVWMachine::rot2_p
private

Rotation matrix to go from old system to new system.

Definition at line 260 of file UVWMachine.h.

RotMatrix casacore::UVWMachine::rot3_p
private

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

Definition at line 262 of file UVWMachine.h.

RotMatrix casacore::UVWMachine::rot4_p
private

Rotation Matrix to project UV-plane onto.

Definition at line 264 of file UVWMachine.h.

RotMatrix casacore::UVWMachine::uvproj_p
private

UVW rotation including projection.

Definition at line 268 of file UVWMachine.h.

RotMatrix casacore::UVWMachine::uvrot_p
private

UVW rotation.

Definition at line 266 of file UVWMachine.h.

Bool casacore::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: