crosses

Checks if two geometries crosses.

Synopsis

template<typename Geometry1, typename Geometry2>
bool crosses(Geometry1 const & geometry1, Geometry2 const & geometry2)

Parameters

Type	Concept	Name	Description
Geometry1 const &	Any type fulfilling a Geometry Concept	geometry1	A model of the specified concept
Geometry2 const &	Any type fulfilling a Geometry Concept	geometry2	A model of the specified concept

Returns

Returns true if two geometries crosses

Header

Either

#include <boost/geometry.hpp>

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

Conformance

The function crosses implements function Crosses from the OGC Simple Feature Specification.

Supported geometries

	Point	Segment	Box	Linestring	Ring	Polygon	MultiPoint	MultiLinestring	MultiPolygon	Variant
Point
Segment
Box
Linestring
Ring
Polygon
MultiPoint
MultiLinestring
MultiPolygon
Variant

Examples

Checks if two geometries crosses

#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()
{
    // Checks if the two geometries (here, a polygon and a linestring) crosses or not. 
    bg::model::polygon<bg::model::d2::point_xy<double> > poly;
    bg::read_wkt("POLYGON((0 0,0 3,3 3,3 0,0 0))", poly);
    bg::model::linestring<bg::model::d2::point_xy<double> > line1;
    bg::read_wkt("LINESTRING(1 1,2 2,4 4)", line1);
    bool check_crosses = bg::crosses(poly, line1);
    if (check_crosses) {
         std::cout << "Crosses: Yes" << std::endl;
    } else {
        std::cout << "Crosses: No" << std::endl;
    }

    // Edge case: linestring just touches the polygon but doesn't crosses it.
    bg::model::linestring<bg::model::d2::point_xy<double> > line2;
    bg::read_wkt("LINESTRING(1 1,1 2,1 3)", line2);
    check_crosses = bg::crosses(poly, line2);
    if (check_crosses) {
         std::cout << "Crosses: Yes" << std::endl;
    } else {
        std::cout << "Crosses: No" << std::endl;
    }

    return 0;
}

Convenient namespace alias

Output:

Crosses: Yes
Crosses: No