| Home | Libraries | People | FAQ | More

##### densify

Densify a geometry.

###### Synopsis

    template<typename Geometry, typename Distance>
    void densify(Geometry const & geometry, Geometry & out, Distance const & max_distance)

###### Parameters

Type | Concept | Name | Description
--- | --- | --- | ---
Geometry const & | Any type fulfilling a Geometry Concept | geometry | Input geometry, to be densified
Geometry & | Any type fulfilling a Geometry Concept | out | Output geometry, densified version of the input geometry
Distance const & | A numerical distance measure | max_distance | Distance threshold (in units depending on coordinate system)

###### Header

Either

`#include <boost/geometry.hpp>`

Or

`#include <boost/geometry/algorithms/densify.hpp>`

###### Conformance

The function densify is not defined by OGC.

| Note
PostGIS contains an algorithm ST_Segmentize with the same functionality. See the PostGIS documentation.

###### Behavior

The algorithm divides segments of a geometry if they are longer than passed distance into smaller segments.

| Note
The units of the distance depends on strategy. In order to change the default behavior a user has to create a strategy and pass it explicitly into the algorithm.

###### Example

Shows how to densify a polygon

    #include <iostream>

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

    int main()
    {
        using point_type = boost::geometry::model::d2::point_xy<double>;
        using polygon_type = boost::geometry::model::polygon<point_type>;

        polygon_type poly;
        boost::geometry::read_wkt(
            "POLYGON((0 0,0 10,10 10,10 0,0 0),(1 1,4 1,4 4,1 4,1 1))", poly);

        polygon_type res;

        boost::geometry::densify(poly, res, 6.0);

        std::cout << "densified: " << boost::geometry::wkt(res) << std::endl;

        return 0;
    }

Output:

    densified: POLYGON((0 0,0 5,0 10,5 10,10 10,10 5,10 0,5 0,0 0),(1 1,4 1,4 4,1 4,1 1))

###### See also

- line_interpolate