ArcGIS Developer Help

IForwardStar Interface

Provides access to members that query information about adjacent elements in the logical network.

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.

Description

The IForwardStar interface allows you to access the fundamental connectivity of a network. ("Forward Star" is a term from computer science for a data structure that stores the connectivity of a graph.) The job of IForwardStar is to return information about adjacent elements. An adjacent element is simply a network element connected to another network element. For example, an edge connected to a junction, or a junction connected to a junction via an edge. Quickly finding adjacent elements is the cornerstone of all network solvers.

To use IForwardStar, you start with the FindAdjacent method. FindAdjacent returns the number of adjacent edges to a junction which you use to iterate over the adjacent edges with the QueryAdjacent[elt] methods, where elt is the element type.

The QueryAdjacent[elt] methods return both the adjacent elements as well as the weights of the adjacent elements. An edge weight could be used to represent the cost to reach the adjacent junction. You specify what weight you want returned when you create the ForwardStar with the CreateForwardStar method on the INetwork interface.

When To Use

IForwardStar is used to access the connectivity of a network.

Members

	Name	Description
	FindAdjacent	Finds the edge elements that are adjacent to the given junction element and returns the count.
	Network	Underlying network of this forward star cursor.
	QueryAdjacentEdge	Returns index'th adjacent edge found with FindAdjacent, its orientation, and its weight value.
	QueryAdjacentEdges	Returns the adjacent edges found with FindAdjacent into the specified user-defined array.
	QueryAdjacentJunction	Returns the opposite junction of the index'th adjacent edge found with FindAdjacent, and the weight value for this junction.
	QueryAdjacentJunctions	Returns the opposite junctions of the adjacent edges found with FindAdjacent into the specified user-defined array.
	QueryAtTurn	Returns the turn through which the index'th adjacent edge found with FindAdjacent passes, and the weight value of the turn.
	QueryAtTurns	Returns the turns through which the adjacent edges found with FindAdjacent passes into the user-defined array.

Classes that implement IForwardStar

Classes	Description
ForwardStar	A container for querying information about adjacent elements in the logical network.

[C#]

Not all members are callable from C#. Please use IForwardStarGEN instead.

[Visual Basic .NET]

Not all members are callable from VB.NET. Please use IForwardStarGEN instead.