Boost C++ Libraries

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model::linestring

A linestring (named so by OGC) is a collection (default a vector) of points.

Model of

Linestring Concept

Synopsis

template<typename Point, template< typename, typename > class Container, template< typename > class Allocator>
class model::linestring
{
  // ...
};

Template parameter(s)

Parameter

Default

Description

typename Point

Any type fulfilling a Point Concept

template< typename, typename > class Container

std::vector

container type, for example std::vector, std::deque

template< typename > class Allocator

std::allocator

container-allocator-type

Constructor(s)

Function

Description

Parameters

linestring()

Default constructor, creating an empty \1.

template<typename Iterator>
linestring(Iterator begin, Iterator end)

Constructor with begin and end, filling the \1.

Iterator: begin:

Iterator: end:

linestring(std::initializer_list< Point > l)

Constructor taking std::initializer_list, filling the \1.

std::initializer_list< Point >: l:

Header

Either

#include <boost/geometry/geometries/geometries.hpp>

Or

#include <boost/geometry/geometries/linestring.hpp>

Examples

Declaration and use of the Boost.Geometry model::linestring, modelling the Linestring Concept

#include <iostream>
#include <boost/geometry.hpp>
#include <boost/geometry/geometries/geometries.hpp>

namespace bg = boost::geometry;

int main()
{
    typedef bg::model::point<double, 2, bg::cs::cartesian> point_t;
    typedef bg::model::linestring<point_t> linestring_t;

    linestring_t ls1; 1

#if !defined(BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX) \
 && !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST)

    linestring_t ls2{{0.0, 0.0}, {1.0, 0.0}, {1.0, 2.0}}; 2

#endif

    bg::append(ls1, point_t(0.0, 0.0)); 3
    bg::append(ls1, point_t(1.0, 0.0));
    bg::append(ls1, point_t(1.0, 2.0));

    double l = bg::length(ls1);

    std::cout << l << std::endl;

    return 0;
}

1

Default-construct a linestring.

2

Construct a linestring containing three points, using C++11 unified initialization syntax.

3

Append point.

Output:

3

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