Boost C++ Libraries

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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

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 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;

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)
```