|  | Home | Libraries | People | FAQ | More | 
Checks if the first geometry is inside or on border the second geometry.
The free function covered_by checks if the first geometry is inside or on border the second geometry.
template<typename Geometry1, typename Geometry2> bool covered_by(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 which might be inside or on the border of the second geometry | 
| Geometry2 const & | Any type fulfilling a Geometry Concept | geometry2 | A model of the specified concept which might cover the first geometry | 
true if geometry1 is inside of or on the border of geometry2, else false
Either
            #include <boost/geometry.hpp>
          
Or
            #include <boost/geometry/algorithms/covered_by.hpp>
          
The function covered_by is not defined by OGC.
| ![[Note]](../../../../../../../../doc/src/images/note.png) | Note | 
|---|---|
| Both PostGIS and Oracle contain an algorithm with the same name and the same functionality. See the PostGIS documentation. | 
| Point | Segment | Box | Linestring | Ring | Polygon | MultiPoint | MultiLinestring | MultiPolygon | Variant | |
|---|---|---|---|---|---|---|---|---|---|---|
| Point | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| Segment | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| Box | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| Linestring | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| Ring | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| Polygon | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| MultiPoint | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| MultiLinestring | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| MultiPolygon | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| Variant | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
                       | 
| ![[Note]](../../../../../../../../doc/src/images/note.png) | Note | 
|---|---|
| In this status matrix above: columns are types of first parameter and rows are types of second parameter. So a point can be checked to be covered by a polygon, but not vice versa. | 
Linear
| ![[Note]](../../../../../../../../doc/src/images/note.png) | Note | 
|---|---|
| 
              The difference with the  | 
Checks if the first geometry is inside or on border the second geometry
#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 first geometry is inside or on border the second geometry. bg::model::polygon<bg::model::d2::point_xy<double> > poly1; bg::read_wkt("POLYGON((0 2,0 3,2 4,1 2,0 2))", poly1); bg::model::polygon<bg::model::d2::point_xy<double> > poly2; bg::read_wkt("POLYGON((0 4,3 4,2 2,0 1,0 4))", poly2); bool check_covered = bg::covered_by(poly1, poly2); if (check_covered) { std::cout << "Covered: Yes" << std::endl; } else { std::cout << "Covered: No" << std::endl; } bg::model::polygon<bg::model::d2::point_xy<double> > poly3; bg::read_wkt("POLYGON((-1 -1,-3 -4,-7 -7,-4 -3,-1 -1))", poly3); check_covered = bg::covered_by(poly1, poly3); if (check_covered) { std::cout << "Covered: Yes" << std::endl; } else { std::cout << "Covered: No" << std::endl; } // This should return true since both polygons are same, so they are lying on each other. check_covered = bg::covered_by(poly1, poly1); if (check_covered) { std::cout << "Covered: Yes" << std::endl; } else { std::cout << "Covered: No" << std::endl; } return 0; }
Output:
Covered: YesCovered: No Covered: Yes