Package org.locationtech.jts.noding.snapround

Class MCIndexSnapRounder

java.lang.Object

org.locationtech.jts.noding.snapround.MCIndexSnapRounder

All Implemented Interfaces:

Noder

public class MCIndexSnapRounder
extends Object
implements Noder

Uses Snap Rounding to compute a rounded, fully noded arrangement from a set of SegmentStrings. Implements the Snap Rounding technique described in papers by Hobby, Guibas & Marimont, and Goodrich et al. Snap Rounding assumes that all vertices lie on a uniform grid; hence the precision model of the input must be fixed precision, and all the input vertices must be rounded to that precision.

This implementation uses a monotone chains and a spatial index to speed up the intersection tests.

This implementation appears to be fully robust using an integer precision model. It will function with non-integer precision models, but the results are not 100% guaranteed to be correctly noded.

Version:

1.7

Field Summary

Fields

Modifier and Type	Field	Description
private LineIntersector	li
private Collection	nodedSegStrings
private MCIndexNoder	noder
private final PrecisionModel	pm
private MCIndexPointSnapper	pointSnapper
private final double	scaleFactor

Constructor Summary

Constructors

Constructor	Description
MCIndexSnapRounder(PrecisionModel pm)

Method Summary

Modifier and Type	Method	Description
private void	checkCorrectness(Collection inputSegmentStrings)
private void	computeIntersectionSnaps(Collection snapPts)	Snaps segments to nodes created by segment intersections.
void	computeNodes(Collection inputSegmentStrings)	Computes the noding for a collection of SegmentStrings.
void	computeVertexSnaps(Collection edges)	Snaps segments to all vertices.
private void	computeVertexSnaps(NodedSegmentString e)	Snaps segments to the vertices of a Segment String.
private List	findInteriorIntersections(Collection segStrings, LineIntersector li)	Computes all interior intersections in the collection of SegmentStrings, and returns their Coordinates.
Collection	getNodedSubstrings()	Returns a Collection of fully noded SegmentStrings.
private void	snapRound(Collection segStrings, LineIntersector li)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

pm

private final PrecisionModel pm

li

private LineIntersector li

scaleFactor

private final double scaleFactor

noder

private MCIndexNoder noder

pointSnapper

private MCIndexPointSnapper pointSnapper

nodedSegStrings

private Collection nodedSegStrings

Constructor Details

MCIndexSnapRounder

public MCIndexSnapRounder(PrecisionModel pm)

Method Details

getNodedSubstrings

public Collection getNodedSubstrings()

Description copied from interface: Noder

Returns a Collection of fully noded SegmentStrings. The SegmentStrings have the same context as their parent.

Specified by:

getNodedSubstrings in interface Noder

Returns:

a Collection of SegmentStrings

computeNodes

public void computeNodes(Collection inputSegmentStrings)

Description copied from interface: Noder

Computes the noding for a collection of SegmentStrings. Some Noders may add all these nodes to the input SegmentStrings; others may only add some or none at all.

Specified by:

computeNodes in interface Noder

Parameters:

inputSegmentStrings - a collection of SegmentStrings to node

checkCorrectness

private void checkCorrectness(Collection inputSegmentStrings)

snapRound

private void snapRound(Collection segStrings,
 LineIntersector li)

findInteriorIntersections

private List findInteriorIntersections(Collection segStrings,
 LineIntersector li)

Computes all interior intersections in the collection of SegmentStrings, and returns their Coordinates. Does NOT node the segStrings.

Returns:

a list of Coordinates for the intersections

computeIntersectionSnaps

private void computeIntersectionSnaps(Collection snapPts)

Snaps segments to nodes created by segment intersections.

computeVertexSnaps

public void computeVertexSnaps(Collection edges)

Snaps segments to all vertices.

Parameters:

edges - the list of segment strings to snap together

computeVertexSnaps

private void computeVertexSnaps(NodedSegmentString e)

Snaps segments to the vertices of a Segment String.