lsst::meas::base::CentroidTransform Class Reference

Base for centroid measurement transformations. More...

#include <CentroidUtilities.h>

Inheritance diagram for lsst::meas::base::CentroidTransform:

Public Member Functions
	CentroidTransform (std::string const &name, afw::table::SchemaMapper &mapper)
virtual void	operator() (afw::table::SourceCatalog const &inputCatalog, afw::table::BaseCatalog &outputCatalog, afw::geom::SkyWcs const &wcs, afw::image::PhotoCalib const &photoCalib) const

Protected Member Functions
void	checkCatalogSize (afw::table::BaseCatalog const &cat1, afw::table::BaseCatalog const &cat2) const
	Ensure that catalogs have the same size. More...

Protected Attributes
std::string	_name

Detailed Description

Base for centroid measurement transformations.

Provides a basic transform from centroid plus associated uncertainty to celestial position with uncertainty. The basic "flag" attribute for the measurement algorithm is propagated to the output.

Subclasses should define a constructor which take a Control argument corresponding to the measurement algorithm being transformed and ensure that any other necessary flags are propagated.

Definition at line 168 of file CentroidUtilities.h.

Constructor & Destructor Documentation

CentroidTransform()

lsst::meas::base::CentroidTransform::CentroidTransform	(	std::string const &	name,
		afw::table::SchemaMapper &	mapper
	)

Definition at line 121 of file CentroidUtilities.cc.

        : BaseTransform{name} {
    // Map the flag through to the output
    mapper.addMapping(mapper.getInputSchema().find<afw::table::Flag>(name + "_flag").key);

    // Add keys for the coordinates
    auto &s = mapper.editOutputSchema();
    _coordKey = afw::table::CoordKey::addFields(s, name, "ICRS coordinates");

    // If the centroid has an error key we also include one on the celestial
    // coordinates; otherwise, it isn't necessary. Note that if we provide for
    // errors in celestial coordinates, we always need the full covariance.
    if (CentroidResultKey(mapper.getInputSchema()[name]).getCentroidErr().isValid()) {
        std::vector<afw::table::Key<ErrElement> > sigma(2);
        std::vector<afw::table::Key<ErrElement> > cov(1);
        sigma[0] = s.addField<ErrElement>(s.join(name, "raErr"), "1-sigma uncertainty on RA", "rad");
        sigma[1] = s.addField<ErrElement>(s.join(name, "decErr"), "1-sigma uncertainty on dec", "rad");
        cov[0] = s.addField<ErrElement>(s.join(name, "ra_dec_Cov"), "Uncertainty covariance in RA and dec",
                                        "rad^2");
        _coordErrKey = afw::table::CovarianceMatrixKey<ErrElement, 2>(sigma, cov);
    }
}

Member Function Documentation

checkCatalogSize()

void lsst::meas::base::BaseTransform::checkCatalogSize ( afw::table::BaseCatalog const &  cat1, afw::table::BaseCatalog const &  cat2  ) const

inlineprotectedinherited

Ensure that catalogs have the same size.

Parameters

[in]	cat1	Catalog for comparison
[in]	cat2	Catalog for comparison

Exceptions

LengthError

Catalog sizes do not match

Definition at line 102 of file Transform.h.

                                                                                                  {
        if (cat1.size() != cat2.size()) {
            throw LSST_EXCEPT(pex::exceptions::LengthError, "Catalog size mismatch");
        }
    }

operator()()

void lsst::meas::base::CentroidTransform::operator() ( afw::table::SourceCatalog const &  inputCatalog, afw::table::BaseCatalog &  outputCatalog, afw::geom::SkyWcs const &  wcs, afw::image::PhotoCalib const &  photoCalib  ) const

virtual

Implements lsst::meas::base::BaseTransform.

Definition at line 144 of file CentroidUtilities.cc.

                                                                               {
    checkCatalogSize(inputCatalog, outputCatalog);
    CentroidResultKey centroidResultKey(inputCatalog.getSchema()[_name]);

    afw::table::SourceCatalog::const_iterator inSrc = inputCatalog.begin();
    afw::table::BaseCatalog::iterator outSrc = outputCatalog.begin();

    for (; inSrc != inputCatalog.end() && outSrc != outputCatalog.end(); ++inSrc, ++outSrc) {
        CentroidResult centroidResult = centroidResultKey.get(*inSrc);

        _coordKey.set(*outSrc, wcs.pixelToSky(centroidResult.getCentroid()));

        if (centroidResultKey.getCentroidErr().isValid()) {
            CentroidCov centroidCov = centroidResult.getCentroidErr();
            if (!(std::isnan(centroidCov(0, 0)) || std::isnan(centroidCov(1, 1)))) {
                auto transform = wcs.linearizePixelToSky(centroidResult.getCentroid(), geom::radians)
                                         .getLinear()
                                         .getMatrix();
                _coordErrKey.set(*outSrc, (transform * centroidResult.getCentroidErr().cast<double>() *
                                           transform.transpose())
                                                  .cast<ErrElement>());
            }
        }
    }
}

Member Data Documentation

_name

std::string lsst::meas::base::BaseTransform::_name

protectedinherited

Definition at line 107 of file Transform.h.

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

• /j/snowflake/release/lsstsw/stack/Linux64/meas_base/18.1.0-7-g9d75d83+9/include/lsst/meas/base/CentroidUtilities.h
• /j/snowflake/release/lsstsw/stack/Linux64/meas_base/18.1.0-7-g9d75d83+9/src/CentroidUtilities.cc