A class in which to store and allow read-only access to image metadata. More...

#include <ImageMetaData.h>

Public Member Functions
template<class T >
	ImageMetaData (const ImageInterface< T > &image)
Int	spectralAxisNumber () const
	Get the axis number of the spectral axis of this image (0-based).
uInt	nChannels () const
	Get the number of channels in this image.
Bool	isChannelNumberValid (const uInt chan) const
	Is the specified channel number valid for this image?
Int	spectralCoordinateNumber () const
	Get the coordinate number of the spectral axis of this image (0-based).
Bool	hasSpectralAxis () const
	Does this image have a spectral (frequency) axis?
Int	polarizationCoordinateNumber () const
	Get the coordinate number of the polarization axis of this image (0-based).
Int	polarizationAxisNumber () const
	Get the axis number of the polarization axis of this image (0-based).
Bool	hasPolarizationAxis () const
	Does this image have a polarization axis?
Int	stokesPixelNumber (const String &stokesString) const
	Get the pixel number on the polarization axis of the specified stokes parameter.
uInt	nStokes () const
	Get the number of stokes parameters in this image.
Bool	isStokesValid (const String &stokesString) const
	is the specified stokes parameter present in the image?
Int	directionCoordinateNumber () const
	Get the zero based direction coordinate number.
Bool	hasDirectionCoordinate () const
	does this image have a direction coordinate?
Vector< Int >	directionAxesNumbers () const
	Get the direction axes numbers for this image.
Vector< Int >	directionShape () const
	Get the shape of the direction axes.
Bool	areChannelAndStokesValid (String &message, const uInt chan, const String &stokesString) const
	if the specified stokes parameter is valid.
Private Attributes
const CoordinateSystem &	itsCoordinates
IPosition	itsShape

Detailed Description

A class in which to store and allow read-only access to image metadata.

Intended use:

Public interface

Prerequisite

ImageInterface

Etymology

The ImageMetaData class name is derived from its role as holding image metadata.

Synopsis

The ImageMetaData object is meant to allow access to image metadata (eg, shape, coordinate system info such as spectral and polarization axes numbers, etc).

Example

Construct an object of this class by passing the associated image to the constructor.

    PagedImage<Float> myImage("myImage");
    ImageMetaData<Float> myImageMetaData(myImage);

Motivation

This class is meant to provide an object-oriented interface for accessing image metadata without polluting the ImageInterface and CoordinateSystem classes with these methods.

Definition at line 73 of file ImageMetaData.h.

Constructor & Destructor Documentation

template<class T >

casa::ImageMetaData::ImageMetaData ( const ImageInterface< T > & image ) [inline]

Definition at line 76 of file ImageMetaData.h.

Member Function Documentation

Bool casa::ImageMetaData::areChannelAndStokesValid	(	String &	message,
		const uInt	chan,
		const String &	stokesString
	)			const

if the specified stokes parameter is valid.

A message suitable for error notification is returned in the form of an in-out parameter if one or both of these is invalid.

Vector<Int> casa::ImageMetaData::directionAxesNumbers ( ) const

Get the direction axes numbers for this image.

Returns a two element Vector if there is a direction coordinate, if not returns a zero element vector.

Int casa::ImageMetaData::directionCoordinateNumber ( ) const

Get the zero based direction coordinate number.

Vector<Int> casa::ImageMetaData::directionShape ( ) const

Get the shape of the direction axes.

Returns a two element Vector if there is a direction coordinate, if not returns a zero element vector.

Bool casa::ImageMetaData::hasDirectionCoordinate ( ) const

does this image have a direction coordinate?

Bool casa::ImageMetaData::hasPolarizationAxis ( ) const

Does this image have a polarization axis?

Bool casa::ImageMetaData::hasSpectralAxis ( ) const

Does this image have a spectral (frequency) axis?

Bool casa::ImageMetaData::isChannelNumberValid ( const uInt chan ) const

Is the specified channel number valid for this image?

Bool casa::ImageMetaData::isStokesValid ( const String & stokesString ) const

is the specified stokes parameter present in the image?

uInt casa::ImageMetaData::nChannels ( ) const

Get the number of channels in this image.

uInt casa::ImageMetaData::nStokes ( ) const

Get the number of stokes parameters in this image.

Int casa::ImageMetaData::polarizationAxisNumber ( ) const

Get the axis number of the polarization axis of this image (0-based).

Return -1 if this image does not have a polarization axis.

Int casa::ImageMetaData::polarizationCoordinateNumber ( ) const

Get the coordinate number of the polarization axis of this image (0-based).

This is generally not the same as the axis number because the direction (eg RA, Dec) coordinate counts as only one coordinate, not two. Yes I know its confusing. Here's an example, say you have an image with axes, RA, Dec, Stokes, Frequency. The polarization coordinate number would be 1 since RA, Dec make up a single direction coordinate. But, the polarization axis number would be 2, because RA and Dec are counted seperately in this case. Its important (and very confusing) to be clear about this difference or things will break. Return -1 if this image does not have a polarization axis.

Int casa::ImageMetaData::spectralAxisNumber ( ) const

Get the axis number of the spectral axis of this image (0-based).

Int casa::ImageMetaData::spectralCoordinateNumber ( ) const

Get the coordinate number of the spectral axis of this image (0-based).

This is generally not the same as the axis number because the direction (eg RA, Dec) coordinate counts as only one coordinate, not two. Yes I know its confusing. Here's an example, say you have an image with axes, RA, Dec, Stokes, Frequency. The spectral coordinate number would be 2 since RA, Dec make up a single direction coordinate. But, the spectral axis number would be 3, because RA and Dec are counted seperately in this case. Its important (and very confusing) to be clear about this difference or things will break.

Int casa::ImageMetaData::stokesPixelNumber ( const String & stokesString ) const

Get the pixel number on the polarization axis of the specified stokes parameter.

If the specified stokes parameter does not exist in the image, the value returned is not gauranteed to be anything other than outside the range of 0 to nStokes-1 inclusive. Return -1 if the specified stokes parameter is not present or if this image does not have a polarization axis.