perimeter

Calculates the perimeter of a geometry.

Description

The function perimeter returns the perimeter of a geometry, using the default distance-calculation-strategy

Synopsis

template<typename Geometry>
default_length_result<Geometry>::type perimeter(Geometry const & geometry)

Parameters

Type	Concept	Name	Description
Geometry const &	Any type fulfilling a Geometry Concept	geometry	A model of the specified concept

Returns

The calculated perimeter

Header

Either

#include <boost/geometry.hpp>

#include <boost/geometry/algorithms/perimeter.hpp>

Conformance

The function perimeter is not defined by OGC.

	Note
	PostGIS contains an algorithm with the same name and the same functionality. See the PostGIS documentation.

Behavior

Case	Behavior
pointlike (e.g. point)	Returns zero
linear (e.g. linestring)	Returns zero
areal (e.g. polygon)	Returns the perimeter

Complexity

Linear

Example

Calculate the perimeter of a polygon

#include <iostream>

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

namespace bg = boost::geometry; 

int main()
{
    // Calculate the perimeter of a cartesian polygon
    bg::model::polygon<bg::model::d2::point_xy<double> > poly;
    bg::read_wkt("POLYGON((0 0,3 4,5 -5,-2 -4, 0 0))", poly);
    double perimeter = bg::perimeter(poly);
    std::cout << "Perimeter: " << perimeter << std::endl;

    return 0;
}

Convenient namespace alias

Output:

Perimeter: 25.7627