lsst::afw::geom::TransformMap< CoordSysT > Class Template Reference

#include <TransformMap.h>

Public Types
typedef std::map< CoordSysT, boost::shared_ptr< XYTransform const > >	Transforms
typedef CoordSysT	CoordSys

Public Member Functions
	TransformMap (CoordSysT const &nativeCoordSys, Transforms const &transforms)
	TransformMap ()
	null implementation to make SWIG willing to wrap a map that contains these More...
Point2D	transform (Point2D const &fromPoint, CoordSysT const &fromSys, CoordSysT const &toCoordSys) const
std::vector< Point2D >	transform (std::vector< Point2D > const &pointList, CoordSysT const &fromCoordSys, CoordSysT const &toCoordSys) const
CoordSysT	getNativeCoordSys () const
std::vector< CoordSysT >	getCoordSysList () const
bool	contains (CoordSysT const &coordSys) const
boost::shared_ptr< XYTransform const >	operator[] (CoordSysT const &coordSys) const
Transforms::const_iterator	begin () const
Transforms::const_iterator	end () const
size_t	size () const

Private Attributes
CoordSysT	_nativeCoordSys
	native coordinate system More...
Transforms	_transforms
	map of coordSys: XYTransform More...

Detailed Description

template<typename CoordSysT>
class lsst::afw::geom::TransformMap< CoordSysT >

A registry of 2-dimensional coordinate transforms, templated on a coordinate system type

Contains a native CoordSysT and a map of CoordSysT:XYTransform (including an identity transform entry for native CoordSysT). Each map entry is an XYTransform whose forwardTransform method converts from the native system to CoordSysT.

TransformMap supports transforming between any two supported CoordSysT using the transform method. It also allows iteration over the map of CoordSysT: XYTransform:

• In C++ the iterator is a CoordSysT, CONST_PTR(XYTransform) pair.
• In Python, the iterator returns a CoordSysT; use TransformMap[CoordSysT] to access the XYTransform.

If CoordSysT is not a plain old data type or std::string then:

• CoordSysT must have a default constructor (no arguments), so SWIG can wrap some collections
• CoordSysT must support operator< to support use as a key in std::map
• CoordSysT should support operator== and operator!= for common sense
• CoordSysT should support hash in Python to support proper behavior in sets and dicts
• You must overload ostream operator<<(CoordSysT const &) to support error messages in TransformMap For an example see ../cameraGeom/CameraSys.h (CameraSys is used as a CoordSysT) and its SWIG wrapper.

At some point we will switch to using std::unordered_map (once we switch to C++11 and a SWIG that supports its collection classes). At that point instead of requiring CoordSysT.operator<, it will be necessary to specialize std::hash<CoordSysT>(CoordSysT const &).

Warning

: code that instantiates a templated version of TransformMap must include lsst/afw/geom/TransformMapImpl.h (else you will get linker errors).

Definition at line 65 of file TransformMap.h.

Member Typedef Documentation

template<typename CoordSysT>

typedef CoordSysT lsst::afw::geom::TransformMap< CoordSysT >::CoordSys

Definition at line 68 of file TransformMap.h.

template<typename CoordSysT>

typedef std::map<CoordSysT, boost::shared_ptr< XYTransform const> > lsst::afw::geom::TransformMap< CoordSysT >::Transforms

Definition at line 67 of file TransformMap.h.

Constructor & Destructor Documentation

template<typename CoordSysT>

lsst::afw::geom::TransformMap< CoordSysT >::TransformMap ( CoordSysT const &  nativeCoordSys, Transforms const &  transforms  )

explicit

Construct a TransformMap

Note

If transformMap includes a transform for nativeCoordSys then it is used (without checking); if not, then a unity transform is added.

Exceptions

pexExcept::InvalidParameterError

if you specify the same coordSys more than once, or a transform is specified where coordSys == nativeCoordSys

Parameters

nativeCoordSys	Native coordinate system for this registry
transforms	a map of coordSys:xyTransform, where xyTransform.forward transforms coordSys to nativeCoordSys

Definition at line 38 of file TransformMapImpl.h.

  :
    _nativeCoordSys(nativeCoordSys), _transforms()
{
    for (typename Transforms::const_iterator trIter = transforms.begin();
        trIter != transforms.end(); ++trIter) {
        if (_transforms.count(trIter->first) > 0) {
            std::ostringstream os;
            os << "Duplicate coordSys \"" << trIter->first << "\"";
            throw LSST_EXCEPT(lsst::pex::exceptions::InvalidParameterError, os.str());
        } else if (trIter->first == _nativeCoordSys) {
            std::ostringstream os;
            os << "coordSys \"" << trIter->first << "\" matches nativeCoordSys";
            throw LSST_EXCEPT(lsst::pex::exceptions::InvalidParameterError, os.str());
        }
        _transforms.insert(*trIter);
    }

    // insert identity transform for nativeCoordSys, if not already provided
    if (!contains(nativeCoordSys)) {
        _transforms.insert(std::make_pair(nativeCoordSys,
            boost::make_shared<IdentityXYTransform>()));
    }
}

template<typename CoordSysT>

lsst::afw::geom::TransformMap< CoordSysT >::TransformMap ( )

explicit

null implementation to make SWIG willing to wrap a map that contains these

Definition at line 66 of file TransformMapImpl.h.

: _nativeCoordSys(), _transforms() {}

Member Function Documentation

template<typename CoordSysT>

Transforms::const_iterator lsst::afw::geom::TransformMap< CoordSysT >::begin ( ) const

inline

Definition at line 142 of file TransformMap.h.

{ return _transforms.begin(); }

template<typename CoordSysT>

bool lsst::afw::geom::TransformMap< CoordSysT >::contains

(

CoordSysT const &

coordSys

)

const

Return true if the coordinate system is supported

In Python this is renamed to contains; use as follows: coordSys in transformMap

Parameters

coordSys

coordinate system

Definition at line 146 of file TransformMapImpl.h.

        {
    return _transforms.find(coordSys) != _transforms.end();
}

template<typename CoordSysT>

Transforms::const_iterator lsst::afw::geom::TransformMap< CoordSysT >::end ( ) const

inline

Definition at line 144 of file TransformMap.h.

{ return _transforms.end(); }

template<typename CoordSysT >

std::vector< CoordSysT > lsst::afw::geom::TransformMap< CoordSysT >::getCoordSysList

(

)

const

Get a list of supported coordinate systems

Returns

a list of coordinate systems, in undefined order.

Definition at line 123 of file TransformMapImpl.h.

                                                                    {
    std::vector<CoordSysT> coordSysList;
    for (typename Transforms::const_iterator trIter = _transforms.begin();
        trIter != _transforms.end(); ++trIter) {
        coordSysList.push_back(trIter->first);
    }
    return coordSysList;
}

template<typename CoordSysT>

CoordSysT lsst::afw::geom::TransformMap< CoordSysT >::getNativeCoordSys ( ) const

inline

Definition at line 112 of file TransformMap.h.

{ return _nativeCoordSys; }

template<typename CoordSysT>

boost::shared_ptr< XYTransform const > lsst::afw::geom::TransformMap< CoordSysT >::operator[]

(

CoordSysT const &

coordSys

)

const

Get an XYTransform that transforms from coordSys to nativeCoordSys in the forward direction

Returns

a shared_ptr to an XYTransform

Exceptions

pexExcept::InvalidParameterError

if coordSys is unknown

Parameters

coordSys

coordinate system whose XYTransform is wanted

Definition at line 133 of file TransformMapImpl.h.

        {
    typename Transforms::const_iterator const foundIter = _transforms.find(coordSys);
    if (foundIter == _transforms.end()) {
        std::ostringstream os;
        os << "Registry does not support coordSys \"" << coordSys << "\"";
        throw LSST_EXCEPT(lsst::pex::exceptions::InvalidParameterError, os.str());
    }
    return foundIter->second;
}

template<typename CoordSysT>

size_t lsst::afw::geom::TransformMap< CoordSysT >::size ( ) const

inline

Definition at line 146 of file TransformMap.h.

{ return _transforms.size(); }

template<typename CoordSysT>

Point2D lsst::afw::geom::TransformMap< CoordSysT >::transform	(	Point2D const &	fromPoint,
		CoordSysT const &	fromSys,
		CoordSysT const &	toCoordSys
	)		const

Convert a point from one coordinate system to another

Returns

the transformed value as a Point2D

Exceptions

pexExcept::InvalidParameterError

if toCoordSys is unknown

Parameters

fromPoint	point from which to transform
fromSys	coordinate system from which to transform
toCoordSys	coordinate system to which to transform

Definition at line 70 of file TransformMapImpl.h.

        {
    if (fromCoordSys == toCoordSys) {
        return fromPoint;
    }

    // transform fromSys -> nativeSys -> toSys
    CONST_PTR(XYTransform) fromTransform = (*this)[fromCoordSys];
    CONST_PTR(XYTransform) toTransform = (*this)[toCoordSys];
    return toTransform->forwardTransform(fromTransform->reverseTransform(fromPoint));
}

template<typename CoordSysT>

std::vector< Point2D > lsst::afw::geom::TransformMap< CoordSysT >::transform	(	std::vector< Point2D > const &	pointList,
		CoordSysT const &	fromCoordSys,
		CoordSysT const &	toCoordSys
	)		const

Convert a list of Point2D from one coordinate system to another

Exceptions

pexExcept::InvalidParameterError

if fromCoordSys or toCoordSys is unknown

Parameters

pointList	list of points to transform
fromCoordSys	from coordinate system
toCoordSys	to coordinate system

Definition at line 86 of file TransformMapImpl.h.

        {
    if (fromCoordSys == toCoordSys) {
        return pointList;
    }

    std::vector<Point2D> outList;

    // transform pointList from fromCoordSys to native coords, filling outList
    if (fromCoordSys != _nativeCoordSys) {
        CONST_PTR(XYTransform) fromTransform = (*this)[fromCoordSys];
        for (std::vector<Point2D>::const_iterator fromPtIter = pointList.begin();
            fromPtIter != pointList.end(); ++fromPtIter) {
            outList.push_back(fromTransform->reverseTransform(*fromPtIter));
        }
    } else {
        for (std::vector<Point2D>::const_iterator fromPtIter = pointList.begin();
            fromPtIter != pointList.end(); ++fromPtIter) {
            outList.push_back(*fromPtIter);
        }
    }

    // transform outList from native coords to toCoordSys, in place
    if (toCoordSys != _nativeCoordSys) {
        CONST_PTR(XYTransform) toTransform = (*this)[toCoordSys];
        for (std::vector<Point2D>::iterator nativePtIter = outList.begin();
            nativePtIter != outList.end(); ++nativePtIter) {
            *nativePtIter = toTransform->forwardTransform(*nativePtIter);
        }
    }
    return outList;
}

Member Data Documentation

template<typename CoordSysT>

CoordSysT lsst::afw::geom::TransformMap< CoordSysT >::_nativeCoordSys

private

native coordinate system

Definition at line 149 of file TransformMap.h.

template<typename CoordSysT>

Transforms lsst::afw::geom::TransformMap< CoordSysT >::_transforms

private

map of coordSys: XYTransform

Definition at line 150 of file TransformMap.h.

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

• /home/lsstsw/stack/Linux64/afw/11.0-2-g04d2804/include/lsst/afw/geom/TransformMap.h
• /home/lsstsw/stack/Linux64/afw/11.0-2-g04d2804/include/lsst/afw/geom/TransformMapImpl.h