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casa::LinearCoordinate Class Reference

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

#include <LinearCoordinate.h>

Inheritance diagram for casa::LinearCoordinate:
casa::Coordinate

List of all members.

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).
LinearCoordinateoperator= (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) 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< StringworldAxisNames () const
 Return the requested attribute.
virtual Vector< DoublereferenceValue () const
virtual Vector< Doubleincrement () const
virtual Matrix< DoublelinearTransform () const
virtual Vector< DoublereferencePixel () const
virtual Vector< StringworldAxisUnits () 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 CoordinatemakeFourierCoordinate (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 Coordinateclone () const
 Make a copy of the LinearCoordinate using new.

Static Public Member Functions

static LinearCoordinaterestore (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

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

To Do

Definition at line 120 of file LinearCoordinate.h.


Constructor & Destructor Documentation

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

naxes gives the number of axes in the Coordinate.

casa::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.

casa::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.

casa::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

Copy constructor (copy semantics).

Destructor.


Member Function Documentation

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

Make a copy of the LinearCoordinate using new.

The caller is responsible for calling delete.

Implements casa::Coordinate.

void casa::LinearCoordinate::copy ( const LinearCoordinate other) [private]

Copy private data.

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

Implements casa::Coordinate.

Implements casa::Coordinate.

virtual Coordinate* casa::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 casa::Coordinate.

void casa::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 casa::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.

Implements casa::Coordinate.

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

Implements casa::Coordinate.

virtual uInt casa::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 casa::Coordinate.

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

Implements casa::Coordinate.

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

Assignment (copy semantics).

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

Implements casa::Coordinate.

Implements casa::Coordinate.

static LinearCoordinate* casa::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 casa::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 casa::Coordinate.

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

Implements casa::Coordinate.

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

Implements casa::Coordinate.

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

Implements casa::Coordinate.

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

Implements casa::Coordinate.

virtual Bool casa::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 casa::Coordinate.

virtual Bool casa::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 casa::Coordinate.

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

Returns the String "Linear".

Implements casa::Coordinate.

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

Implements casa::Coordinate.

virtual Bool casa::LinearCoordinate::toWorld ( Vector< Double > &  world,
const Vector< Double > &  pixel 
) 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.

Implements casa::Coordinate.

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

Returns Coordinate::LINEAR.

Implements casa::Coordinate.

Return the requested attribute.

Implements casa::Coordinate.

Implements casa::Coordinate.


Member Data Documentation

mutable ::wcsprm casa::LinearCoordinate::wcs_p [private]

An interface to the WCSLIB linear transformation routines.

Definition at line 254 of file LinearCoordinate.h.


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