| Home | Libraries | People | FAQ | More

##### to_wkt

WKT-string formulating function.

###### Synopsis

    template<typename Geometry>
    std::string to_wkt(Geometry const & geometry)

###### Parameters

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

###### Header

Either

`#include <boost/geometry.hpp>`

Or

`#include <boost/geometry/io/wkt/write.hpp>`

###### Conformance

The function to_wkt implements function AsText from the OGC Simple Feature Specification.

| Note
to_wkt is not named "AsText" or "as_text" because Boost.Geometry also supports other textformats (svg, dsv)

###### Example

Shows the usage of to_wkt

    #include <iostream>

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

    int main()
    {
        namespace geom = boost::geometry;
        typedef geom::model::d2::point_xy<double> point_type;

        point_type point = geom::make<point_type>(3, 2);
        geom::model::polygon<point_type> polygon;
        geom::append(geom::exterior_ring(polygon), geom::make<point_type>(0, 0));
        geom::append(geom::exterior_ring(polygon), geom::make<point_type>(0, 4));
        geom::append(geom::exterior_ring(polygon), geom::make<point_type>(4, 4));
        geom::append(geom::exterior_ring(polygon), geom::make<point_type>(4, 0));
        geom::append(geom::exterior_ring(polygon), geom::make<point_type>(0, 0));

        std::cout << boost::geometry::to_wkt(point) << std::endl;
        std::cout << boost::geometry::to_wkt(polygon) << std::endl;

        point_type point_frac = geom::make<point_type>(3.141592654, 27.18281828);
        geom::model::polygon<point_type> polygon_frac;
        geom::append(geom::exterior_ring(polygon_frac), geom::make<point_type>(0.00000, 0.00000));
        geom::append(geom::exterior_ring(polygon_frac), geom::make<point_type>(0.00000, 4.00001));
        geom::append(geom::exterior_ring(polygon_frac), geom::make<point_type>(4.00001, 4.00001));
        geom::append(geom::exterior_ring(polygon_frac), geom::make<point_type>(4.00001, 0.00000));
        geom::append(geom::exterior_ring(polygon_frac), geom::make<point_type>(0.00000, 0.00000));

        std::cout << boost::geometry::to_wkt(point_frac, 3) << std::endl;
        std::cout << boost::geometry::to_wkt(polygon_frac, 3) << std::endl;

        return 0;
    }

Output:

    POINT(3 2)
    POLYGON((0 0,0 4,4 4,4 0,0 0))
    POINT(3.14 27.2)
    POLYGON((0 0,0 4,4 4,4 0,0 0))

###### See also

- Read WKT
- From WKT
- WKT streaming manipulator