Table of Contents

Class DouglasPeuckerSimplifier

Namespace
NetTopologySuite.Simplify
Assembly
NetTopologySuite.dll

Simplifies a Geometry using the Douglas-Peucker algorithm.

public class DouglasPeuckerSimplifier
Inheritance
DouglasPeuckerSimplifier
Inherited Members

Remarks

Ensures that any polygonal geometries returned are valid. Simple lines are not guaranteed to remain simple after simplification. All geometry types are handled. Empty and point geometries are returned unchanged. Empty geometry components are deleted.

Note that in general D-P does not preserve topology - e.g. polygons can be split, collapse to lines or disappear holes can be created or disappear, and lines can cross. To simplify point while preserving topology use TopologySafeSimplifier. (However, using D-P is significantly faster).

KNOWN BUGS: In some cases the approach used to clean invalid simplified polygons can distort the output geometry severely.

Constructors

DouglasPeuckerSimplifier(Geometry)

Creates a simplifier for a given geometry.

public DouglasPeuckerSimplifier(Geometry inputGeom)

Parameters

inputGeom Geometry

The geometry to simplify.

See Also

Properties

DistanceTolerance

The distance tolerance for the simplification.

public double DistanceTolerance { get; set; }

Property Value

double

Remarks

All vertices in the simplified geometry will be within this distance of the original geometry. The tolerance value must be non-negative.

See Also

EnsureValidTopology

Controls whether simplified polygons will be "fixed" to have valid topology.

public bool EnsureValidTopology { get; set; }

Property Value

bool

Remarks

The caller may choose to disable this because:

  • valid topology is not required
  • fixing topology is a relative expensive operation
  • in some pathological cases the topology fixing operation may either fail or run for too long
The default is to fix polygon topology.
See Also

Methods

GetResultGeometry()

Gets the simplified geometry.

public Geometry GetResultGeometry()

Returns

Geometry

The simplified geometry.

See Also

Simplify(Geometry, double)

Simplifies a geometry using a given tolerance.

public static Geometry Simplify(Geometry geom, double distanceTolerance)

Parameters

geom Geometry

The geometry to simplify.

distanceTolerance double

The tolerance to use.

Returns

Geometry

A simplified version of the geometry.

See Also

See Also

TopologyPreservingSimplifier