makeWcs.cc

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// -*- lsst-c++ -*-

/* 
 * LSST Data Management System
 * Copyright 2008, 2009, 2010 LSST Corporation.
 * 
 * This product includes software developed by the
 * LSST Project (http://www.lsst.org/).
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the LSST License Statement and 
 * the GNU General Public License along with this program.  If not, 
 * see <http://www.lsstcorp.org/LegalNotices/>.
 */
 
#include "boost/make_shared.hpp"
#include "Eigen/Core"
#include "lsst/afw/image/Wcs.h"
#include "lsst/afw/image/TanWcs.h"

namespace except = lsst::pex::exceptions; 
namespace afwImg = lsst::afw::image;

afwImg::Wcs::Ptr afwImg::makeWcs(
        PTR(lsst::daf::base::PropertySet) const& metadata, 
        bool stripMetadata                              
                                )
{
    std::string ctype1;
    if (metadata->exists("CTYPE1")) {
        ctype1 = metadata->getAsString("CTYPE1");
    } else {
        return PTR(Wcs)();
    }

    afwImg::Wcs::Ptr wcs;               // we can't use make_shared as ctor is private
    if (ctype1.substr(5, 3) == "TAN") {
        wcs = afwImg::Wcs::Ptr(new afwImg::TanWcs(metadata));
    } else if (ctype1.substr(5, 3) == "TPV") {
        PTR(daf::base::PropertySet) _metadata = metadata->deepCopy();
        _metadata->set<std::string>("CTYPE1", "RA---TAN");
        _metadata->set<std::string>("CTYPE2", "DEC--TAN");
        _metadata->set<bool>("TPV_WCS", true);

        wcs = afwImg::Wcs::Ptr(new afwImg::TanWcs(_metadata));
    } else {
        wcs = afwImg::Wcs::Ptr(new afwImg::Wcs(metadata));
    }

    //If keywords LTV[1,2] are present, the image on disk is already a subimage, so
    //we should shift the wcs to allow for this.
    std::string key = "LTV1";
    if (metadata->exists(key)) {
        wcs->shiftReferencePixel(-metadata->getAsDouble(key), 0);
    }

    key = "LTV2";
    if (metadata->exists(key) ) {
        wcs->shiftReferencePixel(0, -metadata->getAsDouble(key));
    }

    if (stripMetadata) {
        afwImg::detail::stripWcsKeywords(metadata, wcs);
    }

    return wcs;
}
    
afwImg::Wcs::Ptr afwImg::makeWcs(
    lsst::afw::coord::Coord const & crval, 
    lsst::afw::geom::Point2D const & crpix, 
    double CD11,                   
    double CD12,                   
    double CD21,                   
    double CD22                    
    ) {
    Eigen::Matrix2d CD;
    CD << CD11, CD12, CD21, CD22;
    lsst::afw::geom::Point2D crvalTmp;
    crvalTmp[0] = crval.toIcrs().getLongitude().asDegrees();
    crvalTmp[1] = crval.toIcrs().getLatitude().asDegrees();
    return afwImg::Wcs::Ptr(new lsst::afw::image::Wcs(crvalTmp, crpix, CD));
}