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Checks if a geometry are spatially equal.
The free function equals checks if the first geometry is spatially equal the second geometry. Spatially equal means that the same point set is included. A box can therefore be spatially equal to a ring or a polygon, or a linestring can be spatially equal to a multi-linestring or a segment. This only works theoretically, not all combinations are implemented yet.
template<typename Geometry1, typename Geometry2> bool equals(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 are spatially equal
Either
            #include <boost/geometry.hpp>
          
Or
            #include <boost/geometry/algorithms/equals.hpp>
          
The function equals implements function Equals from the OGC Simple Feature Specification.
| Point | Segment | Box | Linestring | Ring | Polygon | MultiPoint | MultiLinestring | MultiPolygon | Variant | |
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| Point | 
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| Segment | 
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| Box | 
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| Linestring | 
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| Ring | 
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| Polygon | 
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| MultiPoint | 
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| MultiLinestring | 
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| MultiPolygon | 
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| Variant | 
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Linear
Shows the predicate equals, which returns true if two geometries are spatially equal
#include <iostream> #include <boost/geometry.hpp> #include <boost/geometry/geometries/polygon.hpp> #include <boost/geometry/geometries/adapted/boost_tuple.hpp> BOOST_GEOMETRY_REGISTER_BOOST_TUPLE_CS(cs::cartesian) #include <boost/assign.hpp> int main() { using boost::assign::tuple_list_of; typedef boost::tuple<int, int> point; boost::geometry::model::polygon<point> poly1, poly2; boost::geometry::exterior_ring(poly1) = tuple_list_of(0, 0)(0, 5)(5, 5)(5, 0)(0, 0); boost::geometry::exterior_ring(poly2) = tuple_list_of(5, 0)(0, 0)(0, 5)(5, 5)(5, 0); std::cout << "polygons are spatially " << (boost::geometry::equals(poly1, poly2) ? "equal" : "not equal") << std::endl; boost::geometry::model::box<point> box; boost::geometry::assign_values(box, 0, 0, 5, 5); std::cout << "polygon and box are spatially " << (boost::geometry::equals(box, poly2) ? "equal" : "not equal") << std::endl; return 0; }
Output:
polygons are spatially equal polygon and box are spatially equal