casacore::LinearCoordinate Class Reference

Interconvert between pixel and a linear world coordinate. More...

#include <LinearCoordinate.h>

Inheritance diagram for casacore::LinearCoordinate:

Public Member Functions
	LinearCoordinate (uInt naxes=1)
	The default constructor makes a LinearCoordinate for which pixel and world coordinates are equal.
	LinearCoordinate (const Vector< String > &names, const Vector< String > &units, const Vector< Double > &refVal, const Vector< Double > &inc, const Matrix< Double > &pc, const Vector< Double > &refPix)
	Construct the LinearCoordinate.
	LinearCoordinate (const Vector< String > &names, const Vector< Quantum< Double > > &refVal, const Vector< Quantum< Double > > &inc, const Matrix< Double > &pc, const Vector< Double > &refPix)
	Construct LinearCoordinate with Quantum-based interface.
	LinearCoordinate (const wcsprm &wcs, Bool oneRel=True)
	Constructor from WCS structure; must hold ONLY a linear wcs structure Specify whether the absolute pixel coordinates in the wcs structure are 0- or 1-relative.
	LinearCoordinate (const LinearCoordinate &other)
	Copy constructor (copy semantics).
LinearCoordinate &	operator= (const LinearCoordinate &other)
	Assignment (copy semantics).
virtual	~LinearCoordinate ()
	Destructor.
virtual Coordinate::Type	type () const
	Returns Coordinate::LINEAR.
virtual String	showType () const
	Returns the String "Linear".
virtual uInt	nPixelAxes () const
	Returns the number of pixel/world axes.
virtual uInt	nWorldAxes () const
virtual Bool	toWorld (Vector< Double > &world, const Vector< Double > &pixel, Bool=True) const
	Convert a pixel position to a worl position or vice versa.
virtual Bool	toPixel (Vector< Double > &pixel, const Vector< Double > &world) const
virtual Vector< String >	worldAxisNames () const
	Return the requested attribute.
virtual Vector< Double >	referenceValue () const
virtual Vector< Double >	increment () const
virtual Matrix< Double >	linearTransform () const
virtual Vector< Double >	referencePixel () const
virtual Vector< String >	worldAxisUnits () const
virtual Bool	setWorldAxisNames (const Vector< String > &names)
	Set the value of the requested attributed.
virtual Bool	setReferencePixel (const Vector< Double > &refPix)
virtual Bool	setLinearTransform (const Matrix< Double > &pc)
virtual Bool	setIncrement (const Vector< Double > &inc)
virtual Bool	setReferenceValue (const Vector< Double > &refval)
virtual Bool	setWorldAxisUnits (const Vector< String > &units)
	Set the world axis units.
Bool	overwriteWorldAxisUnits (const Vector< String > &units)
	Overwrite the world axis units with no compatibility checks or adjustment.
virtual Bool	near (const Coordinate &other, Double tol=1e-6) const
	Comparison function.
virtual Bool	near (const Coordinate &other, const Vector< Int > &excludeAxes, Double tol=1e-6) const
virtual Coordinate *	makeFourierCoordinate (const Vector< Bool > &axes, const Vector< Int > &shape) const
	Find the Coordinate for when we Fourier Transform ourselves.
virtual Bool	save (RecordInterface &container, const String &fieldName) const
	Save the LinearCoordinate into the supplied record using the supplied field name.
virtual Coordinate *	clone () const
	Make a copy of the LinearCoordinate using new.
Static Public Member Functions
static LinearCoordinate *	restore (const RecordInterface &container, const String &fieldName)
	Restore the LinearCoordinate from a record.
Private Member Functions
void	copy (const LinearCoordinate &other)
	Copy private data.
void	makeWCS (wcsprm &wcs, uInt naxis, const Vector< Double > &refPix, const Vector< Double > &refVal, const Vector< Double > &incr, const Matrix< Double > &pc, const Vector< String > &units, const Vector< String > &names)
	Make wcs structure.
Private Attributes
mutable::wcsprm	wcs_p
	An interface to the WCSLIB linear transformation routines.

Detailed Description

Interconvert between pixel and a linear world coordinate.

Intended use:

Public interface

Review Status

Reviewed By:: Peter Barnes
Date Reviewed:: 1999/12/24
Test programs:: tLinearCoordinate

Prerequisite

Coordinate defines the fundamental interface to coordinate conversions.

Synopsis

The LinearCoordinate class ties pixel and world axes together through a general linear transformation.

 world = (cdelt * PC * (pixel - crpix)) + crval

Where PC is an NxN matrix; pixel, crval, crpix and world are length N vectors, and cdelt is an NxN diagonal matrix, represented as a length N vector.

The LinearCoordinate can contain several uncoupled axes (similar to the way in which the DirectionCoordinate contains two axes).

Caution: All pixels coordinates are zero relative;

Example

Let's make a LinearCoordinate with just one axis containing a coordinate describing length.

 Vector<Double> crpix(1); crpix = 0.0;
 Vector<Double> crval(1); crval = 100.0;
 Vector<Double> cdelt(1); cdelt = -10.0;
 Matrix<Double> pc(1,1); pc= 0; pc.diagonal() = 1.0;
 Vector<String> name(1);  name = "length";
 Vector<String> units(1); units = "km";
 
 LinearCoordinate lin(names, units, crval, cdelt, pc, crpix);

Now do a coordinate conversion

 Vector<Double> world, pixel(1);
 pixel = 2.0;
 if (!lin.toWorld(world, pixel)) {
 cerr << "Error : " << lin.errorMessage() << endl;
 } else {
 cerr << "pixel, world = " << pixel << world << endl;
 }

The answer should of course be -20km.

Motivation

This class is intended for use with axes which do not have specific coordinate types. A "time" axis would be a good example.

Thrown Exceptions

AipsError

To Do

Allow differing numbers of world and pixel axes. Requires a change in WCS or use of a different library.

Definition at line 120 of file LinearCoordinate.h.

Constructor & Destructor Documentation

casacore::LinearCoordinate::LinearCoordinate ( uInt naxes = 1 )

The default constructor makes a LinearCoordinate for which pixel and world coordinates are equal.

naxes gives the number of axes in the Coordinate.

casacore::LinearCoordinate::LinearCoordinate	(	const Vector< String > &	names,
		const Vector< String > &	units,
		const Vector< Double > &	refVal,
		const Vector< Double > &	inc,
		const Matrix< Double > &	pc,
		const Vector< Double > &	refPix
	)

Construct the LinearCoordinate.

casacore::LinearCoordinate::LinearCoordinate	(	const Vector< String > &	names,
		const Vector< Quantum< Double > > &	refVal,
		const Vector< Quantum< Double > > &	inc,
		const Matrix< Double > &	pc,
		const Vector< Double > &	refPix
	)

Construct LinearCoordinate with Quantum-based interface.

The units of the increment (inc) will be converted to those of the reference value (refVal) which will then serve as the units of the Coordinate.

casacore::LinearCoordinate::LinearCoordinate	(	const wcsprm &	wcs,
		Bool	oneRel = `True`
	)

Constructor from WCS structure; must hold ONLY a linear wcs structure Specify whether the absolute pixel coordinates in the wcs structure are 0- or 1-relative.

The coordinate is always constructed with 0-relative pixel coordinates

casacore::LinearCoordinate::LinearCoordinate ( const LinearCoordinate & other )

Copy constructor (copy semantics).

virtual casacore::LinearCoordinate::~LinearCoordinate ( ) [virtual]

Destructor.

Member Function Documentation

virtual Coordinate* casacore::LinearCoordinate::clone ( ) const [virtual]

Make a copy of the LinearCoordinate using new.

The caller is responsible for calling delete.

Implements casacore::Coordinate.

void casacore::LinearCoordinate::copy ( const LinearCoordinate & other ) [private]

Copy private data.

virtual Vector<Double> casacore::LinearCoordinate::increment ( ) const [virtual]

Implements casacore::Coordinate.

virtual Matrix<Double> casacore::LinearCoordinate::linearTransform ( ) const [virtual]

Implements casacore::Coordinate.

virtual Coordinate* casacore::LinearCoordinate::makeFourierCoordinate	(	const Vector< Bool > &	axes,
		const Vector< Int > &	shape
	)			const `[virtual]`

Find the Coordinate for when we Fourier Transform ourselves.

This pointer must be deleted by the caller. Axes specifies which axes of the Coordinate you wish to transform. Shape specifies the shape of the image associated with all the axes of the Coordinate. Currently the output reference pixel is always shape/2. If the pointer returned is 0, it failed with a message in errorMessage

Reimplemented from casacore::Coordinate.

void casacore::LinearCoordinate::makeWCS	(	wcsprm &	wcs,
		uInt	naxis,
		const Vector< Double > &	refPix,
		const Vector< Double > &	refVal,
		const Vector< Double > &	incr,
		const Matrix< Double > &	pc,
		const Vector< String > &	units,
		const Vector< String > &	names
	)			`[private]`

Make wcs structure.

virtual Bool casacore::LinearCoordinate::near	(	const Coordinate &	other,
		const Vector< Int > &	excludeAxes,
		Double	tol = `1e-6`
	)			const `[virtual]`

virtual Bool casacore::LinearCoordinate::near	(	const Coordinate &	other,
		Double	tol = `1e-6`
	)			const `[virtual]`

Comparison function.

Any private Double data members are compared with the specified fractional tolerance. Don't compare on the specified axes in the Coordinate. If the comparison returns False, method errorMessage contains a message about why.

virtual uInt casacore::LinearCoordinate::nPixelAxes ( ) const [virtual]

Returns the number of pixel/world axes.

The number of axes is arbitrary, however the number of world and pixel axes must at present be the same.

Implements casacore::Coordinate.

virtual uInt casacore::LinearCoordinate::nWorldAxes ( ) const [virtual]

Implements casacore::Coordinate.

LinearCoordinate& casacore::LinearCoordinate::operator= ( const LinearCoordinate & other )

Assignment (copy semantics).

Reimplemented from casacore::Coordinate.

Bool casacore::LinearCoordinate::overwriteWorldAxisUnits ( const Vector< String > & units )

Overwrite the world axis units with no compatibility checks or adjustment.

virtual Vector<Double> casacore::LinearCoordinate::referencePixel ( ) const [virtual]

Implements casacore::Coordinate.

virtual Vector<Double> casacore::LinearCoordinate::referenceValue ( ) const [virtual]

Implements casacore::Coordinate.

static LinearCoordinate* casacore::LinearCoordinate::restore	(	const RecordInterface &	container,
		const String &	fieldName
	)			`[static]`

Restore the LinearCoordinate from a record.

A null pointer means that the restoration did not succeed - probably because fieldName doesn't exist or doesn't contain a CoordinateSystem.

virtual Bool casacore::LinearCoordinate::save	(	RecordInterface &	container,
		const String &	fieldName
	)			const `[virtual]`

Save the LinearCoordinate into the supplied record using the supplied field name.

The field must not already exist, otherwise False is returned.

Implements casacore::Coordinate.

virtual Bool casacore::LinearCoordinate::setIncrement ( const Vector< Double > & inc ) [virtual]

Implements casacore::Coordinate.

virtual Bool casacore::LinearCoordinate::setLinearTransform ( const Matrix< Double > & pc ) [virtual]

Implements casacore::Coordinate.

virtual Bool casacore::LinearCoordinate::setReferencePixel ( const Vector< Double > & refPix ) [virtual]

Implements casacore::Coordinate.

virtual Bool casacore::LinearCoordinate::setReferenceValue ( const Vector< Double > & refval ) [virtual]

Implements casacore::Coordinate.

virtual Bool casacore::LinearCoordinate::setWorldAxisNames ( const Vector< String > & names ) [virtual]

Set the value of the requested attributed.

Note that these just change the internal values, they do not cause any recomputation.

Implements casacore::Coordinate.

virtual Bool casacore::LinearCoordinate::setWorldAxisUnits ( const Vector< String > & units ) [virtual]

Set the world axis units.

Adjust the increment and reference value by the ratio of the old and new units. The units must be compatible with the current units.

Implements casacore::Coordinate.

virtual String casacore::LinearCoordinate::showType ( ) const [virtual]

Returns the String "Linear".

Implements casacore::Coordinate.

virtual Bool casacore::LinearCoordinate::toPixel	(	Vector< Double > &	pixel,
		const Vector< Double > &	world
	)			const `[virtual]`

Implements casacore::Coordinate.

virtual Bool casacore::LinearCoordinate::toWorld	(	Vector< Double > &	world,
		const Vector< Double > &	pixel,
		Bool	= `True`
	)			const `[virtual]`

Convert a pixel position to a worl position or vice versa.

Returns True if the conversion succeeds, otherwise it returns False and method errorMessage returns an error message. The output vectors are appropriately resized. The value of the Bool parameter passed to toWorld() has no effect as this type of coordinate does not support a conversion layer frame.

Implements casacore::Coordinate.

virtual Coordinate::Type casacore::LinearCoordinate::type ( ) const [virtual]

Returns Coordinate::LINEAR.

Implements casacore::Coordinate.

virtual Vector<String> casacore::LinearCoordinate::worldAxisNames ( ) const [virtual]

Return the requested attribute.

Implements casacore::Coordinate.

virtual Vector<String> casacore::LinearCoordinate::worldAxisUnits ( ) const [virtual]

Implements casacore::Coordinate.