Table of Contents

Class MonotoneChainIndexer

Namespace
NetTopologySuite.GeometriesGraph.Index
Assembly
NetTopologySuite.dll

MonotoneChains are a way of partitioning the segments of an edge to allow for fast searching of intersections.

Specifically, a sequence of contiguous line segments is a monotone chain if all the vectors defined by the oriented segments lies in the same quadrant.

Monotone Chains have the following useful properties: the segments within a monotone chain will never intersect each other, and the envelope of any contiguous subset of the segments in a monotone chain is simply the envelope of the endpoints of the subset. Property 1 means that there is no need to test pairs of segments from within the same monotone chain for intersection. Property 2 allows binary search to be used to find the intersection points of two monotone chains. For many types of real-world data, these properties eliminate a large number of segment comparisons, producing substantial speed gains.

Note that due to the efficient intersection test, there is no need to limit the size of chains to obtain fast performance.

public class MonotoneChainIndexer
Inheritance
MonotoneChainIndexer
Inherited Members

Constructors

MonotoneChainIndexer()

public MonotoneChainIndexer()

Methods

GetChainStartIndices(Coordinate[])

Computes the startpoints (and endpoints) of all in monotone chains in this edge

public int[] GetChainStartIndices(Coordinate[] pts)

Parameters

pts Coordinate[]

An array of points

Returns

int[]

An array of startpoints (and endpoints) of monotone chains

OLDGetChainStartIndices(Coordinate[])

public int[] OLDGetChainStartIndices(Coordinate[] pts)

Parameters

pts Coordinate[]

Returns

int[]