Class IndexedFacetDistance

Computes the distance between the facets (segments and vertices) of two Geometrys using a Branch-and-Bound algorithm. The Branch-and-Bound algorithm operates over a traversal of R-trees built on the target and the query geometries.

This approach provides the following benefits:

Performance is dramatically improved due to the use of the R-tree index and the pruning due to the Branch-and-Bound approach
The spatial index on the target geometry is cached which allow reuse in an repeated query situation.

Using this technique is usually much more performant than using the brute-force Distance(Geometry) when one or both input geometries are large, or when evaluating many distance computations against a single geometry.

Inheritance

Object

IndexedFacetDistance

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: NetTopologySuite.Operation.Distance

Assembly: NetTopologySuite.dll

Syntax

public class IndexedFacetDistance

Remarks

This class is thread-safe.

Constructors

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IndexedFacetDistance(Geometry)

Creates a new distance-finding instance for a given target Geometry.

Declaration

public IndexedFacetDistance(Geometry g1)

Parameters

Type	Name	Description
Geometry	g1	A Geometry, which may be of any type.

Remarks

Distances will be computed to all facets of the input geometry. The facets of the geometry are the discrete segments and points contained in its components.

In the case of ILineal and IPuntal inputs, this is equivalent to computing the conventional distance.

In the case of IPolygonal inputs, this is equivalent to computing the distance to the polygon boundaries.

Methods

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Distance(Geometry)

Computes the distance from the base geometry to the given geometry.

Declaration

public double Distance(Geometry g)

Parameters

Type	Name	Description
Geometry	g	The geometry to compute the distance to.

Returns

Type	Description
Double	The computed distance

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Distance(Geometry, Geometry)

Computes the distance between facets of two geometries.

Declaration

public static double Distance(Geometry g1, Geometry g2)

Parameters

Type	Name	Description
Geometry	g1	A geometry
Geometry	g2	A geometry

Returns

Type	Description
Double	The distance between the two geometries

Remarks

For geometries with many segments or points, this can be faster than using a simple distance algorithm.

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IsWithinDistance(Geometry, Geometry, Double)

Tests whether the facets of two geometries lie within a given distance.

Declaration

public static bool IsWithinDistance(Geometry g1, Geometry g2, double distance)

Parameters

Type	Name	Description
Geometry	g1	A geometry
Geometry	g2	A geometry
Double	distance	The distance limit

Returns

Type	Description
Boolean	`true` if two facets lie with the given distance

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IsWithinDistance(Geometry, Double)

Tests whether the base geometry lies within a specified distance of the given geometry.

Declaration

public bool IsWithinDistance(Geometry g, double maxDistance)

Parameters

Type	Name	Description
Geometry	g	The geometry to test
Double	maxDistance	The maximum distance to test

Returns

Type	Description
Boolean	`true` if the geometry lies with the specified distance

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NearestLocations(Geometry)

Computes the nearest locations on the base geometry and the given geometry.

Declaration

public GeometryLocation[] NearestLocations(Geometry g)

Parameters

Type	Name	Description
Geometry	g	Ihe geometry to compute the nearest location to.

Returns

Type	Description
GeometryLocation[]	The nearest locations.

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NearestPoints(Geometry)

Computes the nearest locations on the target geometry and the given geometry.

Declaration

public Coordinate[] NearestPoints(Geometry g)

Parameters

Type	Name	Description
Geometry	g	Ihe geometry to compute the nearest point to.

Returns

Type	Description
Coordinate[]	The nearest points.

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NearestPoints(Geometry, Geometry)

Computes the nearest points of the facets of two geometries.

Declaration

public static Coordinate[] NearestPoints(Geometry g1, Geometry g2)

Parameters

Type	Name	Description
Geometry	g1	A geometry
Geometry	g2	A geometry

Returns

Type	Description
Coordinate[]	The nearest points on the facets of the geometries