org.locationtech.jts.operation.polygonize

Class EdgeRing

java.lang.Object

org.locationtech.jts.operation.polygonize.EdgeRing

class EdgeRing
extends java.lang.Object

Represents a ring of PolygonizeDirectedEdges which form a ring of a polygon. The ring may be either an outer shell or a hole.

Version:

1.7

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	EdgeRing.EnvelopeComparator Compares EdgeRings based on their envelope, using the standard lexicographic ordering.

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.List	deList
private GeometryFactory	factory
private java.util.List	holes
private boolean	isHole
private boolean	isIncluded
private boolean	isIncludedSet
private boolean	isProcessed
private DirectedEdge	lowestEdge
private LinearRing	ring
private Coordinate[]	ringPts
private EdgeRing	shell

Constructor Summary

Constructors

Constructor and Description
EdgeRing(GeometryFactory factory)

Method Summary

Modifier and Type	Method and Description
private void	add(DirectedEdge de) Adds a DirectedEdge which is known to form part of this ring.
private static void	addEdge(Coordinate[] coords, boolean isForward, CoordinateList coordList)
void	addHole(EdgeRing holeER) Adds a hole to the polygon formed by this ring.
void	addHole(LinearRing hole) Adds a hole to the polygon formed by this ring.
void	build(PolygonizeDirectedEdge startDE)
void	computeHole() Computes whether this ring is a hole.
static java.util.List	findDirEdgesInRing(PolygonizeDirectedEdge startDE) Traverses a ring of DirectedEdges, accumulating them into a list.
static EdgeRing	findEdgeRingContaining(EdgeRing testEr, java.util.List shellList) Find the innermost enclosing shell EdgeRing containing the argument EdgeRing, if any.
private Coordinate[]	getCoordinates() Computes the list of coordinates which are contained in this ring.
LineString	getLineString() Gets the coordinates for this ring as a LineString.
EdgeRing	getOuterHole()
Polygon	getPolygon() Computes the Polygon formed by this ring and any contained holes.
LinearRing	getRing() Returns this ring as a LinearRing, or null if an Exception occurs while creating it (such as a topology problem).
EdgeRing	getShell() Gets the shell for this ring.
boolean	hasShell() Tests whether this ring has a shell assigned to it.
boolean	isHole() Tests whether this ring is a hole.
boolean	isIncluded()
boolean	isIncludedSet()
static boolean	isInList(Coordinate pt, Coordinate[] pts) Deprecated.
boolean	isOuterHole() Tests whether this ring is an outer hole.
boolean	isOuterShell() Tests whether this ring is an outer shell.
boolean	isProcessed()
boolean	isValid() Tests if the LinearRing ring formed by this edge ring is topologically valid.
static Coordinate	ptNotInList(Coordinate[] testPts, Coordinate[] pts) Deprecated. Use CoordinateArrays.ptNotInList instead
void	setIncluded(boolean isIncluded)
void	setProcessed(boolean isProcessed)
void	setShell(EdgeRing shell) Sets the containing shell ring of a ring that has been determined to be a hole.
java.lang.String	toString() Gets a string representation of this object.
void	updateIncluded() Updates the included status for currently non-included shells based on whether they are adjacent to an included shell.

Methods inherited from class java.lang.Object

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

Field Detail

factory

private GeometryFactory factory

deList

private java.util.List deList

lowestEdge

private DirectedEdge lowestEdge

ring

private LinearRing ring

ringPts

private Coordinate[] ringPts

holes

private java.util.List holes

shell

private EdgeRing shell

isHole

private boolean isHole

isProcessed

private boolean isProcessed

isIncludedSet

private boolean isIncludedSet

isIncluded

private boolean isIncluded

Constructor Detail

EdgeRing

public EdgeRing(GeometryFactory factory)

Method Detail

findEdgeRingContaining

public static EdgeRing findEdgeRingContaining(EdgeRing testEr,
                                              java.util.List shellList)

Find the innermost enclosing shell EdgeRing containing the argument EdgeRing, if any. The innermost enclosing ring is the smallest enclosing ring. The algorithm used depends on the fact that:
ring A contains ring B iff envelope(ring A) contains envelope(ring B)
This routine is only safe to use if the chosen point of the hole is known to be properly contained in a shell (which is guaranteed to be the case if the hole does not touch its shell)

Returns:

containing EdgeRing, if there is one or null if no containing EdgeRing is found

ptNotInList

public static Coordinate ptNotInList(Coordinate[] testPts,
                                     Coordinate[] pts)

Deprecated. Use CoordinateArrays.ptNotInList instead

Finds a point in a list of points which is not contained in another list of points

Parameters:

testPts - the Coordinates to test

pts - an array of Coordinates to test the input points against

Returns:

a Coordinate from testPts which is not in pts, or null if there is no coordinate not in the list

isInList

public static boolean isInList(Coordinate pt,
                               Coordinate[] pts)

Deprecated.

Tests whether a given point is in an array of points. Uses a value-based test.

Parameters:

pt - a Coordinate for the test point

pts - an array of Coordinates to test

Returns:

true if the point is in the array

findDirEdgesInRing

public static java.util.List findDirEdgesInRing(PolygonizeDirectedEdge startDE)

Traverses a ring of DirectedEdges, accumulating them into a list. This assumes that all dangling directed edges have been removed from the graph, so that there is always a next dirEdge.

Parameters:

startDE - the DirectedEdge to start traversing at

Returns:

a List of DirectedEdges that form a ring

build

public void build(PolygonizeDirectedEdge startDE)

add

private void add(DirectedEdge de)

Adds a DirectedEdge which is known to form part of this ring.

Parameters:

de - the DirectedEdge to add.

isHole

public boolean isHole()

Tests whether this ring is a hole.

Returns:

true if this ring is a hole

computeHole

public void computeHole()

Computes whether this ring is a hole. Due to the way the edges in the polygonization graph are linked, a ring is a hole if it is oriented counter-clockwise.

addHole

public void addHole(LinearRing hole)

Adds a hole to the polygon formed by this ring.

Parameters:

hole - the LinearRing forming the hole.

addHole

public void addHole(EdgeRing holeER)

Adds a hole to the polygon formed by this ring.

Parameters:

hole - the LinearRing forming the hole.

getPolygon

public Polygon getPolygon()

Computes the Polygon formed by this ring and any contained holes.

Returns:

the Polygon formed by this ring and its holes.

isValid

public boolean isValid()

Tests if the LinearRing ring formed by this edge ring is topologically valid.

Returns:

true if the ring is valid

isIncludedSet

public boolean isIncludedSet()

isIncluded

public boolean isIncluded()

setIncluded

public void setIncluded(boolean isIncluded)

getCoordinates

private Coordinate[] getCoordinates()

Computes the list of coordinates which are contained in this ring. The coordinates are computed once only and cached.

Returns:

an array of the Coordinates in this ring

getLineString

public LineString getLineString()

Gets the coordinates for this ring as a LineString. Used to return the coordinates in this ring as a valid geometry, when it has been detected that the ring is topologically invalid.

Returns:

a LineString containing the coordinates in this ring

getRing

public LinearRing getRing()

Returns this ring as a LinearRing, or null if an Exception occurs while creating it (such as a topology problem). Details of problems are written to standard output.

addEdge

private static void addEdge(Coordinate[] coords,
                            boolean isForward,
                            CoordinateList coordList)

setShell

public void setShell(EdgeRing shell)

Sets the containing shell ring of a ring that has been determined to be a hole.

Parameters:

shell - the shell ring

hasShell

public boolean hasShell()

Tests whether this ring has a shell assigned to it.

Returns:

true if the ring has a shell

getShell

public EdgeRing getShell()

Gets the shell for this ring. The shell is the ring itself if it is not a hole, otherwise its parent shell.

Returns:

the shell for this ring

isOuterHole

public boolean isOuterHole()

Tests whether this ring is an outer hole. A hole is an outer hole if it is not contained by a shell.

Returns:

true if the ring is an outer hole.

isOuterShell

public boolean isOuterShell()

Tests whether this ring is an outer shell.

Returns:

true if the ring is an outer shell.

getOuterHole

public EdgeRing getOuterHole()

updateIncluded

public void updateIncluded()

Updates the included status for currently non-included shells based on whether they are adjacent to an included shell.

toString

public java.lang.String toString()

Gets a string representation of this object.

Overrides:

toString in class java.lang.Object

Returns:

a string representing the object

isProcessed

public boolean isProcessed()

Returns:

whether the ring has been processed

setProcessed

public void setProcessed(boolean isProcessed)

Parameters:

isProcessed - whether the ring has been processed