densify (with strategy)

Densify a geometry using a specified strategy.

Synopsis

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

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 strategy)
Strategy const &	A type fulfilling a DensifyStrategy concept	strategy	Densify strategy to be used for densification

Header

Either

#include <boost/geometry.hpp>

#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.

Available Strategies

Example

Shows how to densify a linestring in geographic coordinate system

#include <iostream>

#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point.hpp>
#include <boost/geometry/geometries/linestring.hpp>

int main()
{
    namespace bg = boost::geometry;
    typedef bg::model::point<double, 2, bg::cs::geographic<bg::degree> > point_type;
    typedef bg::model::linestring<point_type> linestring_type;

    linestring_type ls;
    bg::read_wkt("LINESTRING(0 0,1 1)", ls);

    linestring_type res;

    bg::srs::spheroid<double> spheroid(6378137.0, 6356752.3142451793);
    bg::strategy::densify::geographic<> strategy(spheroid);

    boost::geometry::densify(ls, res, 50000.0, strategy);

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

    return 0;
}

Output:

densified: LINESTRING(0 0,0.249972 0.250011,0.499954 0.500017,0.749954 0.750013,1 1)