lsst::meas.astrom.sip::MatchSrcToCatalogue Class Reference

#include <MatchSrcToCatalogue.h>

Public Types
typedef boost::shared_ptr < MatchSrcToCatalogue >	Ptr
typedef boost::shared_ptr < MatchSrcToCatalogue const >	ConstPtr

Public Member Functions
	MatchSrcToCatalogue (afw::table::SimpleCatalog const &catSet, afw::table::SourceCatalog const &imgSet, boost::shared_ptr< afw::image::Wcs const > wcs, afw::geom::Angle dist)
	Create a list of common objects from a catalogue and an image. More...
void	setDist (afw::geom::Angle dist)
	Set a new value for the maximum allowed distance between two matching objects (in ra/dec space) More...
void	setWcs (boost::shared_ptr< afw::image::Wcs const > wcs)
	Set a different Wcs solution. More...
void	setCatSrcSet (afw::table::SimpleCatalog const &catSet)
void	setImgSrcSet (afw::table::SourceCatalog const &srcSet)
	sourceSet is a vector of pointers to Sources. More...
void	findMatches ()
afw::table::ReferenceMatchVector	getMatches ()

Private Member Functions
void	_removeOneToMany ()
void	_removeManyToOne ()

Private Attributes
afw::table::SimpleCatalog	_catSet
	Copy of input catalog. More...
afw::table::SourceCatalog	_imgSet
	Copy of input catalog. More...
afw::table::ReferenceMatchVector	_match
boost::shared_ptr < lsst::afw::image::Wcs const >	_wcs
	List of tuples of matching indices. More...
lsst::afw::geom::Angle	_dist
	How close must two objects be to match. More...

Detailed Description

Match a SourceSet of objects with known ra/dec with a SourceSet of objects with known xy positions Take a catalogue of objects with known positions, a catalogue of objects with known xy, and a wcs to convert one xy <–> ra/dec. This class then finds the set of objects with common ra/dec.

The simplest usage is to create an object of this class, then access the corresponence sets with getMatchedImgSet() and getMatchedCatSet(). Creating the object automatically calculates the sets of corresponences for you. If you are unhappy with these matches, you can change one or more of your input arguments and redo the match with findMatches()

Using this class has the side effect of updating the coord field of the input SourceCatalog (which may be desirable).

Definition at line 58 of file MatchSrcToCatalogue.h.

Member Typedef Documentation

typedef boost::shared_ptr<MatchSrcToCatalogue const> lsst::meas.astrom.sip::MatchSrcToCatalogue::ConstPtr

Definition at line 62 of file MatchSrcToCatalogue.h.

typedef boost::shared_ptr<MatchSrcToCatalogue> lsst::meas.astrom.sip::MatchSrcToCatalogue::Ptr

Definition at line 61 of file MatchSrcToCatalogue.h.

Constructor & Destructor Documentation

lsst::meas.astrom.sip::MatchSrcToCatalogue::MatchSrcToCatalogue	(	afw::table::SimpleCatalog const &	catSet,
		afw::table::SourceCatalog const &	imgSet,
		boost::shared_ptr< afw::image::Wcs const >	wcs,
		afw::geom::Angle	dist
	)

Create a list of common objects from a catalogue and an image.

Take a catSet, i.e a SimpleCatalog giving the true positions of objects in ra/dec space, and an imageSet, i.e. a SourceCatalog of the pixel positions of sources detected on a CCD image. Use the Wcs to calculate the ra/dec of the image source, and then find the subset of objects withcommon positions in the two sets. The returned list of matches is one-to-one, i.e no object in the catalogue is matched twice, and no object in the imageSet is matched twice.

Parameters

catSet	List of catalogue positions with known ra and dec
imgSet	List of image positions with known x and y
wcs	A Wcs object to convert from xy to radec
dist	How close to objects need to be in order to be considered the same

Definition at line 45 of file MatchSrcToCatalogue.cc.

{
    setImgSrcSet(imgSet);
    setCatSrcSet(catSet);
    setDist(dist);
    setWcs(wcs);
}    

Member Function Documentation

void lsst::meas.astrom.sip::MatchSrcToCatalogue::_removeManyToOne ( )

private

This function is identical to _removeOneToMany() except first is replaced with second for the match structures

Definition at line 125 of file MatchSrcToCatalogue.cc.

                                            {
    std::size_t size = _match.size();
    for (std::size_t i=0; i<size; ++i) {
        for (std::size_t j=i+1; j<size; ++j) {
            //If the same Source appears twice
            if (_match[i].second == _match[j].second) {
                //Keep the one with the shorter match distance, and disgard the other
                if (_match[i].distance < _match[j].distance) {
                    _match.erase(_match.begin() + j);
                    size--;
                    j--;
                } else {
                    _match.erase(_match.begin() + i);
                    size--;
                    i--;
                    break;
                }
            }
        }
    }
}

void lsst::meas.astrom.sip::MatchSrcToCatalogue::_removeOneToMany ( )

private

We require that out matches be one to one, i.e any element matches no more than once for either the catalogue or the image. However, our implementation of findMatches uses afw::table::matchRaDec() which does not garauntee that. This function does the (slow) search and removal.

Definition at line 100 of file MatchSrcToCatalogue.cc.

                                           {
    std::size_t size = _match.size();
    for (std::size_t i=0; i<size; ++i) {
        for (std::size_t j=i+1; j<size; ++j) {
            //If the same Source appears twice keep the one with the smaller separation from its match
            if ( _match[i].first == _match[j].first ) {
                //Keep the one with the shorter match distance, and disgard the other
                if (_match[i].distance < _match[j].distance) {
                    _match.erase(_match.begin() + j);
                    size--;
                    j--;
                } else {
                    _match.erase(_match.begin() + i);
                    size--;
                    i--;
                    break;
                }
            }
        }
    }
}

void lsst::meas.astrom.sip::MatchSrcToCatalogue::findMatches

(

)

Definition at line 78 of file MatchSrcToCatalogue.cc.

                                      {
    if (!_imgSet.getTable()->hasCentroidSlot()) {
        throw LSST_EXCEPT(
            pex::exceptions::LogicError,
            "SourceTable passed to MatchSrcToCatalogue does not have its centroid slot set."
        );
    }

    for (afw::table::SourceCatalog::const_iterator i = _imgSet.begin(); i != _imgSet.end(); ++i) {
        i->updateCoord(*_wcs);
    }
    
    _match = afw::table::matchRaDec(_catSet, _imgSet, _dist);

    _removeOneToMany();  
    _removeManyToOne();  
}

afw::table::ReferenceMatchVector lsst::meas.astrom.sip::MatchSrcToCatalogue::getMatches

(

)

Definition at line 148 of file MatchSrcToCatalogue.cc.

                                                             {
    findMatches();
    return _match;
}

void lsst::meas.astrom.sip::MatchSrcToCatalogue::setCatSrcSet

(

afw::table::SimpleCatalog const &

catSet

)

Definition at line 74 of file MatchSrcToCatalogue.cc.

                                                                          {
    _catSet = srcSet;
}

void lsst::meas.astrom.sip::MatchSrcToCatalogue::setDist

(

afw::geom::Angle

dist

)

Set a new value for the maximum allowed distance between two matching objects (in ra/dec space)

Definition at line 57 of file MatchSrcToCatalogue.cc.

                                                   {
    if (dist <= 0) {
        throw LSST_EXCEPT(pex::exceptions::InvalidParameterError, "Distance must be > 0");
    }
    _dist = dist;
}

void lsst::meas.astrom.sip::MatchSrcToCatalogue::setImgSrcSet

(

afw::table::SourceCatalog const &

srcSet

)

sourceSet is a vector of pointers to Sources.

Definition at line 70 of file MatchSrcToCatalogue.cc.

                                                                          {
    _imgSet = srcSet;
}

void lsst::meas.astrom.sip::MatchSrcToCatalogue::setWcs

(

boost::shared_ptr< afw::image::Wcs const >

wcs

)

Set a different Wcs solution.

Definition at line 65 of file MatchSrcToCatalogue.cc.

                                                               {
    _wcs = wcs;
}

Member Data Documentation

afw::table::SimpleCatalog lsst::meas.astrom.sip::MatchSrcToCatalogue::_catSet

private

Copy of input catalog.

Definition at line 83 of file MatchSrcToCatalogue.h.

lsst::afw::geom::Angle lsst::meas.astrom.sip::MatchSrcToCatalogue::_dist

private

How close must two objects be to match.

Definition at line 87 of file MatchSrcToCatalogue.h.

afw::table::SourceCatalog lsst::meas.astrom.sip::MatchSrcToCatalogue::_imgSet

private

Copy of input catalog.

Definition at line 84 of file MatchSrcToCatalogue.h.

afw::table::ReferenceMatchVector lsst::meas.astrom.sip::MatchSrcToCatalogue::_match

private

Definition at line 85 of file MatchSrcToCatalogue.h.

boost::shared_ptr< lsst::afw::image::Wcs const> lsst::meas.astrom.sip::MatchSrcToCatalogue::_wcs

private

List of tuples of matching indices.

Definition at line 86 of file MatchSrcToCatalogue.h.

---

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

• /home/lsstsw/stack/Linux64/meas_astrom/11.0-1-g60db491/include/lsst/meas/astrom/sip/MatchSrcToCatalogue.h
• /home/lsstsw/stack/Linux64/meas_astrom/11.0-1-g60db491/src/sip/MatchSrcToCatalogue.cc