...one of the most highly
regarded and expertly designed C++ library projects in the
world.

— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards

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

Type |
Concept |
Name |
Description |
---|---|---|---|

Geometry const & |
Any type fulfilling a Geometry Concept |
geometry |
input geometry, to be simplified |

Geometry & |
Any type fulfilling a Geometry Concept |
out |
output geometry, simplified version of the input geometry |

Distance const & |
numerical type (int, double, ttmath, ...) |
max_distance |
distance (in units of input coordinates) of a vertex to other segments to be removed |

Either

`#include <boost/geometry.hpp>`

Or

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

The function simplify is not defined by OGC.

Note | |
---|---|

PostGIS contains an algorithm with the same name and the same functionality. See the PostGIS documentation. |

Note | |
---|---|

SQL Server contains an algorithm Reduce() with the same functionality. See the MSDN documentation. |

Simplification is done using Douglas-Peucker (if the default strategy is used).

Note | |
---|---|

Geometries might become invalid by using simplify. The simplification process might create self-intersections. |

Example showing how to simplify a linestring

#include <iostream> #include <boost/geometry.hpp> #include <boost/geometry/geometries/linestring.hpp> #include <boost/geometry/geometries/point_xy.hpp> #include <boost/assign.hpp> using namespace boost::assign; int main() { typedef boost::geometry::model::d2::point_xy<double> xy; boost::geometry::model::linestring<xy> line; line += xy(1.1, 1.1), xy(2.5, 2.1), xy(3.1, 3.1), xy(4.9, 1.1), xy(3.1, 1.9); // Simplify it, using distance of 0.5 units boost::geometry::model::linestring<xy> simplified; boost::geometry::simplify(line, simplified, 0.5); std::cout << " original: " << boost::geometry::dsv(line) << std::endl << "simplified: " << boost::geometry::dsv(simplified) << std::endl; return 0; }

Output:

original: ((1.1, 1.1), (2.5, 2.1), (3.1, 3.1), (4.9, 1.1), (3.1, 1.9)) simplified: ((1.1, 1.1), (3.1, 3.1), (4.9, 1.1), (3.1, 1.9))