Package org.locationtech.jts.operation.overlay

Class LineBuilder

java.lang.Object

org.locationtech.jts.operation.overlay.LineBuilder

public class LineBuilder
extends java.lang.Object

Forms JTS LineStrings out of a the graph of DirectedEdges created by an OverlayOp.

Version:

1.7

Field Summary

Fields

Modifier and Type	Field	Description
private GeometryFactory	geometryFactory
private java.util.List	lineEdgesList
private OverlayOp	op
private PointLocator	ptLocator
private java.util.List	resultLineList

Constructor Summary

Constructors

Constructor	Description
LineBuilder(OverlayOp op, GeometryFactory geometryFactory, PointLocator ptLocator)

Method Summary

Modifier and Type	Method	Description
java.util.List	build(int opCode)
private void	buildLines(int opCode)
private void	collectBoundaryTouchEdge(DirectedEdge de, int opCode, java.util.List edges)	Collect edges from Area inputs which should be in the result but which have not been included in a result area.
private void	collectLineEdge(DirectedEdge de, int opCode, java.util.List edges)	Collect line edges which are in the result.
private void	collectLines(int opCode)
private void	findCoveredLineEdges()	Find and mark L edges which are "covered" by the result area (if any).
private void	labelIsolatedLine(Edge e, int targetIndex)	Label an isolated node with its relationship to the target geometry.
private void	labelIsolatedLines(java.util.List edgesList)

Methods inherited from class java.lang.Object

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

Field Detail

op

private OverlayOp op

geometryFactory

private GeometryFactory geometryFactory

ptLocator

private PointLocator ptLocator

lineEdgesList

private java.util.List lineEdgesList

resultLineList

private java.util.List resultLineList

Constructor Detail

LineBuilder

public LineBuilder(OverlayOp op,
                   GeometryFactory geometryFactory,
                   PointLocator ptLocator)

Method Detail

build

public java.util.List build(int opCode)

Returns:

a list of the LineStrings in the result of the specified overlay operation

findCoveredLineEdges

private void findCoveredLineEdges()

Find and mark L edges which are "covered" by the result area (if any). L edges at nodes which also have A edges can be checked by checking their depth at that node. L edges at nodes which do not have A edges can be checked by doing a point-in-polygon test with the previously computed result areas.

collectLines

private void collectLines(int opCode)

collectLineEdge

private void collectLineEdge(DirectedEdge de,
                             int opCode,
                             java.util.List edges)

Collect line edges which are in the result. Line edges are in the result if they are not part of an area boundary, if they are in the result of the overlay operation, and if they are not covered by a result area.

Parameters:

de - the directed edge to test

opCode - the overlap operation

edges - the list of included line edges

collectBoundaryTouchEdge

private void collectBoundaryTouchEdge(DirectedEdge de,
                                      int opCode,
                                      java.util.List edges)

Collect edges from Area inputs which should be in the result but which have not been included in a result area. This happens ONLY:

• during an intersection when the boundaries of two areas touch in a line segment
• OR as a result of a dimensional collapse.

buildLines

private void buildLines(int opCode)

labelIsolatedLines

private void labelIsolatedLines(java.util.List edgesList)

labelIsolatedLine

private void labelIsolatedLine(Edge e,
                               int targetIndex)

Label an isolated node with its relationship to the target geometry.