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// Boost.Units - A C++ library for zero-overhead dimensional analysis and
// unit/quantity manipulation and conversion
//
// Copyright (C) 2003-2008 Matthias Christian Schabel
// Copyright (C) 2008 Steven Watanabe
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
/**
\file
\brief radar_beam_height.cpp
\details
Demonstrate library usage for user test cases suggested by Michael Fawcett.
Output:
@verbatim
//[radar_beam_height_output
radar range : 300 nmi
earth radius : 6.37101e+06 m
beam height 1 : 18169.7 m
beam height 2 : 9.81085 nmi
beam height 3 : 18169.7 m
beam height 4 : 9.81085 nmi
beam height approx : 59488.4 ft
beam height approx : 18132.1 m
//]
@endverbatim
**/
#include <iostream>
#include <boost/units/conversion.hpp>
#include <boost/units/io.hpp>
#include <boost/units/pow.hpp>
#include <boost/units/systems/si.hpp>
#include <boost/units/systems/si/prefixes.hpp>
using boost::units::length_dimension;
using boost::units::pow;
using boost::units::root;
using boost::units::quantity;
using boost::units::unit;
//[radar_beam_height_class_snippet_1
namespace nautical {
struct length_base_unit :
boost::units::base_unit<length_base_unit, length_dimension, 1>
{
static std::string name() { return "nautical mile"; }
static std::string symbol() { return "nmi"; }
};
typedef boost::units::make_system<length_base_unit>::type system;
/// unit typedefs
typedef unit<length_dimension,system> length;
static const length mile,miles;
} // namespace nautical
// helper for conversions between nautical length and si length
BOOST_UNITS_DEFINE_CONVERSION_FACTOR(nautical::length_base_unit,
boost::units::si::meter_base_unit,
double, 1.852e3);
//]
//[radar_beam_height_class_snippet_2
namespace imperial {
struct length_base_unit :
boost::units::base_unit<length_base_unit, length_dimension, 2>
{
static std::string name() { return "foot"; }
static std::string symbol() { return "ft"; }
};
typedef boost::units::make_system<length_base_unit>::type system;
/// unit typedefs
typedef unit<length_dimension,system> length;
static const length foot,feet;
} // imperial
// helper for conversions between imperial length and si length
BOOST_UNITS_DEFINE_CONVERSION_FACTOR(imperial::length_base_unit,
boost::units::si::meter_base_unit,
double, 1.0/3.28083989501312);
//]
// radar beam height functions
//[radar_beam_height_function_snippet_1
template<class System,typename T>
quantity<unit<boost::units::length_dimension,System>,T>
radar_beam_height(const quantity<unit<length_dimension,System>,T>& radar_range,
const quantity<unit<length_dimension,System>,T>& earth_radius,
T k = 4.0/3.0)
{
return quantity<unit<length_dimension,System>,T>
(pow<2>(radar_range)/(2.0*k*earth_radius));
}
//]
//[radar_beam_height_function_snippet_2
template<class return_type,class System1,class System2,typename T>
return_type
radar_beam_height(const quantity<unit<length_dimension,System1>,T>& radar_range,
const quantity<unit<length_dimension,System2>,T>& earth_radius,
T k = 4.0/3.0)
{
// need to decide which system to use for calculation
const return_type rr(radar_range),
er(earth_radius);
return return_type(pow<2>(rr)/(2.0*k*er));
}
//]
//[radar_beam_height_function_snippet_3
quantity<imperial::length>
radar_beam_height(const quantity<nautical::length>& range)
{
return quantity<imperial::length>
(pow<2>(range/(1.23*nautical::miles/root<2>(imperial::feet))));
}
//]
int main(void)
{
using namespace boost::units;
using namespace boost::units::si;
using namespace nautical;
//[radar_beam_height_snippet_1
const quantity<nautical::length> radar_range(300.0*miles);
const quantity<si::length> earth_radius(6371.0087714*kilo*meters);
const quantity<si::length> beam_height_1(radar_beam_height(quantity<si::length>(radar_range),earth_radius));
const quantity<nautical::length> beam_height_2(radar_beam_height(radar_range,quantity<nautical::length>(earth_radius)));
const quantity<si::length> beam_height_3(radar_beam_height< quantity<si::length> >(radar_range,earth_radius));
const quantity<nautical::length> beam_height_4(radar_beam_height< quantity<nautical::length> >(radar_range,earth_radius));
//]
std::cout << "radar range : " << radar_range << std::endl
<< "earth radius : " << earth_radius << std::endl
<< "beam height 1 : " << beam_height_1 << std::endl
<< "beam height 2 : " << beam_height_2 << std::endl
<< "beam height 3 : " << beam_height_3 << std::endl
<< "beam height 4 : " << beam_height_4 << std::endl
<< "beam height approx : " << radar_beam_height(radar_range)
<< std::endl
<< "beam height approx : "
<< quantity<si::length>(radar_beam_height(radar_range))
<< std::endl << std::endl;
return 0;
}
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