Class TopologyPredicate

The API for strategy classes implementing spatial predicates based on the DE-9IM topology model. Predicate values for specific geometry pairs can be evaluated by RelateNG.

Inheritance

object

TopologyPredicate

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: NetTopologySuite.Operation.RelateNG

Assembly: NetTopologySuite.dll

Syntax

public abstract class TopologyPredicate

Constructors

TopologyPredicate(string)

Creates an instance of this class

Declaration

protected TopologyPredicate(string name)

Parameters

Type	Name	Description
string	name	The name of the predicate

Properties

IsKnown

Tests if the predicate value is known.

Declaration

public abstract bool IsKnown { get; }

Property Value

Type	Description
bool

Name

Gets the name of the predicate

Declaration

public string Name { get; }

Property Value

Type	Description
string

Value

Gets the current value of the predicate result. The value is only valid if IsKnown is true.

Declaration

public abstract bool Value { get; }

Property Value

Type	Description
bool

Methods

Finish()

Indicates that the value of the predicate can be finalized based on its current state.

Declaration

public abstract void Finish()

Init(Dimension, Dimension)

Initializes the predicate for a specific geometric case. This may allow the predicate result to become known if it can be inferred from the dimensions.

Declaration

public virtual void Init(Dimension dimA, Dimension dimB)

Parameters

Type	Name	Description
Dimension	dimA	The dimension of geometry A
Dimension	dimB	The dimension of geometry B

See Also

Dimension

Init(Envelope, Envelope)

Initializes the predicate for a specific geometric case. This may allow the predicate result to become known if it can be inferred from the envelopes.

Declaration

public virtual void Init(Envelope envA, Envelope envB)

Parameters

Type	Name	Description
Envelope	envA	The envelope of geometry A
Envelope	envB	The envelope of geometry B

RequireCovers(bool)

Reports whether this predicate requires that the source cover the target. This is the case if

IM[Ext(Src), Int(Tgt)] = F and IM[Ext(Src), Bdy(Tgt)] = F

If true, this allows a fast result if the source envelope does not cover the target envelope.

Declaration

public virtual bool RequireCovers(bool isSourceA)

Parameters

Type	Name	Description
bool	isSourceA	A flag indicating the source input geometry

Returns

Type	Description
bool	true if the predicate requires checking whether the source covers the target

RequireExteriorCheck(bool)

Reports whether this predicate requires checking if the source input intersects the Exterior of the target input. This is the case if:

IM[Int(Src), Ext(Tgt)] >= 0 or IM[Bdy(Src), Ext(Tgt)] >= 0

If false, this may permit a faster result in some geometric situations.

Declaration

public virtual bool RequireExteriorCheck(bool isSourceA)

Parameters

Type	Name	Description
bool	isSourceA	A flag indicating the source input geometry

Returns

Type	Description
bool	true if the predicate requires checking whether the source intersects the target exterior

RequireInteraction()

Reports whether this predicate requires interaction between the input geometries. This is the case if

IM[I, I] >= 0 or IM[I, B] >= 0 or IM[B, I] >= 0 or IM[B, B] >= 0

This allows a fast result if the envelopes of the geometries are disjoint.

Declaration

public virtual bool RequireInteraction()

Returns

Type	Description
bool	true if the geometries must interact

RequireSelfNoding()

Reports whether this predicate requires self-noding for geometries which contain crossing edges (for example, LineStrings, or GeometryCollections containing lines or polygons which may self-intersect). Self-noding ensures that intersections are computed consistently in cases which contain self-crossings and mutual crossings.

Most predicates require this, but it can be avoided for simple intersection detection (such as in Intersects() and Disjoint(). Avoiding self-noding improves performance for polygonal inputs.

Declaration

public virtual bool RequireSelfNoding()

Returns

Type	Description
bool

UpdateDimension(Location, Location, Dimension)

Updates the entry in the DE-9IM intersection matrix for given {@link Location}s in the input geometries.

If this method is called with a {@link Dimension} value which is less than the current value for the matrix entry, the implementing class should avoid changing the entry if this would cause information loss.

Declaration

public abstract void UpdateDimension(Location locA, Location locB, Dimension dimension)

Parameters

Type	Name	Description
Location	locA	The location on the A axis of the matrix
Location	locB	The location on the B axis of the matrix
Dimension	dimension	The dimension value for the entry

See Also

Location

Dimension