Class CoverageUnion

Unions a valid coverage of polygons or lines in an efficient way.

A polygonal coverage is a collection of Polygons which satisfy the following conditions:

Vector-cleanLine segments within the collection must either be identical or intersect only at endpoints.
Non-overlappingNo two polygons may overlap. Equivalently, polygons must be interior-disjoint.

A linear coverage is a collection of LineStrings which satisfies the Vector-clean condition. Note that this does not require the LineStrings to be fully noded - i.e. they may contain coincident linework. Coincident line segments are dissolved by the union. Currently linear output is not merged (this may be added in a future release.)

No checking is done to determine whether the input is a valid coverage. This is because coverage validation involves segment intersection detection, which is much more expensive than the union phase. If the input is not a valid coverage then in some cases this will be detected during processing and a TopologyException is thrown. Otherwise, the computation will produce output, but it will be invalid.

Unioning a valid coverage implies that no new vertices are created. This means that a precision model does not need to be specified. The precision of the vertices in the output geometry is not changed.

Inheritance

object

CoverageUnion

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: NetTopologySuite.Operation.OverlayNG

Assembly: NetTopologySuite.dll

Syntax

public static class CoverageUnion

Methods

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Union(Geometry)

Unions a valid polygonal coverage or linear network.

Declaration

public static Geometry Union(Geometry coverage)

Parameters

Type	Name	Description
Geometry	coverage	A coverage of polygons or lines

Returns

Type	Description
Geometry	The union of the coverage

Exceptions

Type	Condition
TopologyException	Thrown in some cases if the coverage is invalid