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Checks if two geometries have at least one touching point (tangent - non overlapping)
template<typename Geometry1, typename Geometry2> bool touches(Geometry1 const & geometry1, Geometry2 const & geometry2)
| 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 true if two geometries touch each other
Either
            #include <boost/geometry.hpp>
          
Or
            #include <boost/geometry/algorithms/touches.hpp>
          
The function touches implements function Touches from the OGC Simple Feature Specification.
The version with one parameter is additional and not described in the OGC standard
| ![[Note]](../../../../../../../../doc/src/images/note.png) | Note | 
|---|---|
| Implemented for Point/Linestring/MultiLinestring/Polygon/MultiPolygon. | 
Checks if two geometries have at least one touching point (tangent - non overlapping)
#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 touch bg::model::polygon<bg::model::d2::point_xy<double> > poly1; bg::read_wkt("POLYGON((0 0,0 4,4 4,4 0,0 0))", poly1); bg::model::polygon<bg::model::d2::point_xy<double> > poly2; bg::read_wkt("POLYGON((0 0,0 -4,-4 -4,-4 0,0 0))", poly2); bool check_touches = bg::touches(poly1, poly2); if (check_touches) { std::cout << "Touches: Yes" << std::endl; } else { std::cout << "Touches: No" << std::endl; } bg::model::polygon<bg::model::d2::point_xy<double> > poly3; bg::read_wkt("POLYGON((1 1,0 -4,-4 -4,-4 0,1 1))", poly3); check_touches = bg::touches(poly1, poly3); if (check_touches) { std::cout << "Touches: Yes" << std::endl; } else { std::cout << "Touches: No" << std::endl; } return 0; }
Output:
Touches: YesTouches: No