Eigen assignment to Map

/home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp: In member function ‘virtual std::vector<std::vector<cv::Rect_<int> > > LocalMaxDetector::detect(const std::vector<cv::Mat_<cv::Vec<unsigned char, 3> > >&, IClassifier*)’:
/home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:69:25: error: no match for ‘operator=’ (operand types are ‘Eigen::Map<Eigen::Matrix<float, -1, -1, 1> >’ and ‘float’)
             eigenHeatmap=0.f;
                         ^
In file included from /opt/eigen333/include/eigen3/Eigen/Core:72:0,
                 from /opt/eigen333/include/eigen3/Eigen/Dense:1,
                 from /home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:2:
/opt/eigen333/include/eigen3/Eigen/src/Core/util/Macros.h:827:52: note: candidate: Eigen::Map<MatrixType, MapOptions, StrideType>& Eigen::Map<MatrixType, MapOptions, StrideType>::operator=(const Eigen::Map<MatrixType, MapOptions, StrideType>&) [with PlainObjectType = Eigen::Matrix<float, -1, -1, 1>; int MapOptions = 0; StrideType = Eigen::Stride<0, 0>]
     EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Derived& operator=(const Derived& other) \
                                                    ^
/opt/eigen333/include/eigen3/Eigen/src/Core/util/Macros.h:839:53: note: in expansion of macro ‘EIGEN_INHERIT_ASSIGNMENT_EQUAL_OPERATOR’
 #define EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Derived) EIGEN_INHERIT_ASSIGNMENT_EQUAL_OPERATOR(Derived)
                                                     ^
/opt/eigen333/include/eigen3/Eigen/src/Core/Map.h:155:5: note: in expansion of macro ‘EIGEN_INHERIT_ASSIGNMENT_OPERATORS’
     EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Map)
     ^
/opt/eigen333/include/eigen3/Eigen/src/Core/util/Macros.h:827:52: note:   no known conversion for argument 1 from ‘float’ to ‘const Eigen::Map<Eigen::Matrix<float, -1, -1, 1> >&’
     EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Derived& operator=(const Derived& other) \
                                                    ^
/opt/eigen333/include/eigen3/Eigen/src/Core/util/Macros.h:839:53: note: in expansion of macro ‘EIGEN_INHERIT_ASSIGNMENT_EQUAL_OPERATOR’
 #define EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Derived) EIGEN_INHERIT_ASSIGNMENT_EQUAL_OPERATOR(Derived)
                                                     ^
/opt/eigen333/include/eigen3/Eigen/src/Core/Map.h:155:5: note: in expansion of macro ‘EIGEN_INHERIT_ASSIGNMENT_OPERATORS’
     EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Map)
     ^
In file included from /opt/eigen333/include/eigen3/Eigen/Core:424:0,
                 from /opt/eigen333/include/eigen3/Eigen/Dense:1,
                 from /home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:2:
/opt/eigen333/include/eigen3/Eigen/src/Core/Assign.h:55:30: note: candidate: Derived& Eigen::MatrixBase<Derived>::operator=(const Eigen::MatrixBase<Derived>&) [with Derived = Eigen::Map<Eigen::Matrix<float, -1, -1, 1> >]
 EIGEN_STRONG_INLINE Derived& MatrixBase<Derived>::operator=(const MatrixBase& other)
                              ^
/opt/eigen333/include/eigen3/Eigen/src/Core/Assign.h:55:30: note:   no known conversion for argument 1 from ‘float’ to ‘const Eigen::MatrixBase<Eigen::Map<Eigen::Matrix<float, -1, -1, 1> > >&’
In file included from /opt/eigen333/include/eigen3/Eigen/Core:415:0,
                 from /opt/eigen333/include/eigen3/Eigen/Dense:1,
                 from /home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:2:
/opt/eigen333/include/eigen3/Eigen/src/Core/MatrixBase.h:146:14: note: candidate: template<class OtherDerived> Derived& Eigen::MatrixBase<Derived>::operator=(const Eigen::DenseBase<OtherDerived>&) [with OtherDerived = OtherDerived; Derived = Eigen::Map<Eigen::Matrix<float, -1, -1, 1> >]
     Derived& operator=(const DenseBase<OtherDerived>& other);
              ^
/opt/eigen333/include/eigen3/Eigen/src/Core/MatrixBase.h:146:14: note:   template argument deduction/substitution failed:
/home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:69:25: note:   mismatched types ‘const Eigen::DenseBase<Derived>’ and ‘float’
             eigenHeatmap=0.f;
                         ^
In file included from /opt/eigen333/include/eigen3/Eigen/Core:415:0,
                 from /opt/eigen333/include/eigen3/Eigen/Dense:1,
                 from /home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:2:
/opt/eigen333/include/eigen3/Eigen/src/Core/MatrixBase.h:150:14: note: candidate: template<class OtherDerived> Derived& Eigen::MatrixBase<Derived>::operator=(const Eigen::EigenBase<OtherDerived>&) [with OtherDerived = OtherDerived; Derived = Eigen::Map<Eigen::Matrix<float, -1, -1, 1> >]
     Derived& operator=(const EigenBase<OtherDerived>& other);
              ^
/opt/eigen333/include/eigen3/Eigen/src/Core/MatrixBase.h:150:14: note:   template argument deduction/substitution failed:
/home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:69:25: note:   mismatched types ‘const Eigen::EigenBase<Derived>’ and ‘float’
             eigenHeatmap=0.f;
                         ^
In file included from /opt/eigen333/include/eigen3/Eigen/Core:415:0,
                 from /opt/eigen333/include/eigen3/Eigen/Dense:1,
                 from /home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:2:
/opt/eigen333/include/eigen3/Eigen/src/Core/MatrixBase.h:154:14: note: candidate: template<class OtherDerived> Derived& Eigen::MatrixBase<Derived>::operator=(const Eigen::ReturnByValue<OtherDerived>&) [with OtherDerived = OtherDerived; Derived = Eigen::Map<Eigen::Matrix<float, -1, -1, 1> >]
     Derived& operator=(const ReturnByValue<OtherDerived>& other);
              ^
/opt/eigen333/include/eigen3/Eigen/src/Core/MatrixBase.h:154:14: note:   template argument deduction/substitution failed:
/home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:69:25: note:   mismatched types ‘const Eigen::ReturnByValue<Derived>’ and ‘float’
             eigenHeatmap=0.f;
                         ^
In file included from /opt/eigen333/include/eigen3/Eigen/Core:448:0,
                 from /opt/eigen333/include/eigen3/Eigen/Dense:1,
                 from /home/lars/programming/FSD/vision/src/Detector/LocalMaxDetector.cpp:2:
/opt/eigen333/include/eigen3/Eigen/src/Core/MapBase.h:284:14: note: candidate: Derived& Eigen::MapBase<Derived, 1>::operator=(const Eigen::MapBase<Derived, 1>&) [with Derived = Eigen::Map<Eigen::Matrix<float, -1, -1, 1> >]
     Derived& operator=(const MapBase& other)