AffineGT.h

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/*  Copyright (C) 2008 National Institute For Space Research (INPE) - Brazil.

    This file is part of the TerraLib - a Framework for building GIS enabled applications.

    TerraLib is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License,
    or (at your option) any later version.

    TerraLib 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 Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with TerraLib. See COPYING. If not, write to
    TerraLib Team at <terralib-team@terralib.org>.
 */

/*!
  \file terralib/geometry/AffineGT.h

  \brief 2D Affine Geometric transformation.
*/

#ifndef __TERRALIB_GEOMETRY_INTERNAL_AFFINEGT_H
#define __TERRALIB_GEOMETRY_INTERNAL_AFFINEGT_H

// TerraLib
#include "Config.h"
#include "GeometricTransformation.h"

// Boost
#include <boost/concept_check.hpp>
#include <boost/numeric/ublas/matrix.hpp>

namespace te
{
  namespace gm
  {
    /*!
      \class AffineGT

      \brief 2D Affine Geometric transformation.

      \note The transformation parameters (inside GTParameters::m_directParameters) are disposed on the following form:

      \code
            u = a.x + b.y + c
            v = d.x + e.y + f
            
            | u |   | a b c |   | x |
            | v | = | d e f | * | y |
            | 1 |   | 0 0 1 |   | 1 |
                
            |u0|   |x0   y0  1  0   0  0|.|a|
            |v0|   |0    0   0 x0  y0  1| |b|
            |u1| = |x1   y1  1  0   0  0| |c|
            |v1|   |0    0   0 x1  y1  1| |d|
            |..|   |....................| |e|
            |..|   |....................| |f|

        GTParameters::m_directParameters = [ a b c d e f ]
      \endcode
    */
    class TEGEOMEXPORT AffineGT : public GeometricTransformation
    {
      public:
        
        /*! \brief Default constructor. */
        AffineGT();

        /*! \brief Destructor. */
        ~AffineGT();

        const std::string& getName() const;

        bool isValid(const GTParameters& params) const;

        void directMap(const GTParameters& params,
                       const double& pt1X,
                       const double& pt1Y,
                       double& pt2X,
                       double& pt2Y) const;

        void inverseMap(const GTParameters& params,
                        const double& pt2X,
                        const double& pt2Y,
                        double& pt1X,
                        double& pt1Y) const;

        unsigned int getMinRequiredTiePoints() const;

        GeometricTransformation* clone() const;

        /*!
          \brief Returns the basic set of transform parameters given by the decomposition of a given affine transformation parameters as described above.

          \param transfParams    Input affine transformation parameters.
          \param translationX    X axis translation (combination of a squeeze and scaling).
          \param translationY    Y  axis translation (combination of a squeeze and scaling).
          \param scalingFactorX  X axis scaling.
          \param scalingFactorX  Y axis scaling.
          \param skew            Skew.
          \param squeeze         Aspect ratio changes.
          \param scaling         Uniform scaling.
          \param rotation        Rotation angle (radians).

          \return true if ok, false on errors.
        */
        static bool decompose(const std::vector< double >& transfParams,
                              double& translationX, double& translationY,
                              double& scalingFactorX, double& scalingFactorY, double& skew,
                              double& squeeze, double& scaling, double& rotation);

      protected:
        
        // Variables used by method computeParameters        
        mutable unsigned int m_computeParameters_tiepointsSize;
        mutable unsigned int m_computeParameters_index1;
        mutable unsigned int m_computeParameters_index2;   
        mutable unsigned int m_computeParameters_tpIdx;
        mutable boost::numeric::ublas::matrix< double > m_computeParameters_L;
        mutable boost::numeric::ublas::matrix< double > m_computeParameters_A;
        mutable boost::numeric::ublas::matrix< double > m_computeParameters_At;
        mutable boost::numeric::ublas::matrix< double > m_computeParameters_N;
        mutable boost::numeric::ublas::matrix< double > m_computeParameters_U;
        mutable boost::numeric::ublas::matrix< double > m_computeParameters_N_inv; 
        mutable boost::numeric::ublas::matrix< double > m_computeParameters_X;
        mutable boost::numeric::ublas::matrix< double > m_computeParameters_XExpanded;
        mutable boost::numeric::ublas::matrix< double > m_computeParameters_XExpandedInv;

        bool computeParameters(GTParameters& params) const;
    };

  } // end namespace gm
}   // end namespace te

#endif  // __TERRALIB_GEOMETRY_INTERNAL_GAFFINEGT_H