...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Area calculation for cartesian points.
Calculates area using the Surveyor's formula, a wellknown triangulation algorithm
template<typename PointOfSegment, typename CalculationType> class strategy::area::surveyor { // ... };
Parameter 
Default 
Description 

typename PointOfSegment 
segment point type 

typename CalculationType 
void 
numeric type for calculation (e.g. high precision); if void then it is extracted automatically from the coordinate type and (if necessary) promoted to floating point 
Function 
Description 
Parameters 
Returns 

void apply(PointOfSegment const & p1, PointOfSegment const & p2, summation & state)

PointOfSegment const &: p1: PointOfSegment const &: p2: summation &: state: 

return_type result(summation const & state)

summation const &: state: 
#include <boost/geometry/strategies/cartesian/area_surveyor.hpp>