Class Polygonizer
- java.lang.Object
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- org.locationtech.jts.operation.polygonize.Polygonizer
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public class Polygonizer extends java.lang.Object
Polygonizes a set ofGeometry
s which contain linework that represents the edges of a planar graph. All types of Geometry are accepted as input; the constituent linework is extracted as the edges to be polygonized. The processed edges must be correctly noded; that is, they must only meet at their endpoints. Polygonization will accept incorrectly noded input but will not form polygons from non-noded edges, and reports them as errors.The Polygonizer reports the follow kinds of errors:
- Dangles - edges which have one or both ends which are not incident on another edge endpoint
- Cut Edges - edges which are connected at both ends but which do not form part of polygon
- Invalid Ring Lines - edges which form rings which are invalid (e.g. the component lines contain a self-intersection)
- Version:
- 1.7
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Nested Class Summary
Nested Classes Modifier and Type Class Description private static class
Polygonizer.LineStringAdder
Adds every linear element in aGeometry
into the polygonizer graph.
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Field Summary
Fields Modifier and Type Field Description protected java.util.List
cutEdges
protected java.util.Collection
dangles
private boolean
extractOnlyPolygonal
private GeometryFactory
geomFactory
protected PolygonizeGraph
graph
protected java.util.List
holeList
protected java.util.List
invalidRingLines
private boolean
isCheckingRingsValid
private Polygonizer.LineStringAdder
lineStringAdder
protected java.util.List
polyList
protected java.util.List
shellList
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Constructor Summary
Constructors Constructor Description Polygonizer()
Creates a polygonizer with the sameGeometryFactory
as the inputGeometry
s.Polygonizer(boolean extractOnlyPolygonal)
Creates a polygonizer and allow specifying if only polygons which form a valid polygonal geometry are to be extracted.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
add(java.util.Collection geomList)
Adds a collection of geometries to the edges to be polygonized.void
add(Geometry g)
Add aGeometry
to the edges to be polygonized.private void
add(LineString line)
Adds a linestring to the graph of polygon edges.private static void
assignHolesToShells(java.util.List holeList, java.util.List shellList)
private static void
assignHoleToShell(EdgeRing holeER, java.util.List shellList)
private static java.util.List
extractPolygons(java.util.List shellList, boolean includeAll)
private static void
findDisjointShells(java.util.List shellList)
private static void
findOuterShells(java.util.List shellList)
For each outer hole finds and includes a single outer shell.private void
findShellsAndHoles(java.util.List edgeRingList)
private void
findValidRings(java.util.List edgeRingList, java.util.List validEdgeRingList, java.util.List invalidRingList)
java.util.Collection
getCutEdges()
Gets the list of cut edges found during polygonization.java.util.Collection
getDangles()
Gets the list of dangling lines found during polygonization.Geometry
getGeometry()
Gets a geometry representing the polygons formed by the polygonization.java.util.Collection
getInvalidRingLines()
Gets the list of lines forming invalid rings found during polygonization.java.util.Collection
getPolygons()
Gets the list of polygons formed by the polygonization.private void
polygonize()
Performs the polygonization, if it has not already been carried out.void
setCheckRingsValid(boolean isCheckingRingsValid)
Allows disabling the valid ring checking, to optimize situations where invalid rings are not expected.
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Field Detail
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lineStringAdder
private Polygonizer.LineStringAdder lineStringAdder
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graph
protected PolygonizeGraph graph
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dangles
protected java.util.Collection dangles
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cutEdges
protected java.util.List cutEdges
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invalidRingLines
protected java.util.List invalidRingLines
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holeList
protected java.util.List holeList
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shellList
protected java.util.List shellList
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polyList
protected java.util.List polyList
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isCheckingRingsValid
private boolean isCheckingRingsValid
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extractOnlyPolygonal
private boolean extractOnlyPolygonal
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geomFactory
private GeometryFactory geomFactory
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Constructor Detail
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Polygonizer
public Polygonizer()
Creates a polygonizer with the sameGeometryFactory
as the inputGeometry
s. The output mask is#ALL_POLYS
.
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Polygonizer
public Polygonizer(boolean extractOnlyPolygonal)
Creates a polygonizer and allow specifying if only polygons which form a valid polygonal geometry are to be extracted.- Parameters:
extractOnlyPolygonal
- true if only polygons which form a valid polygonal geometry are to be extracted
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Method Detail
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add
public void add(java.util.Collection geomList)
Adds a collection of geometries to the edges to be polygonized. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted and used.- Parameters:
geomList
- a list ofGeometry
s with linework to be polygonized
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add
public void add(Geometry g)
Add aGeometry
to the edges to be polygonized. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted and used- Parameters:
g
- aGeometry
with linework to be polygonized
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add
private void add(LineString line)
Adds a linestring to the graph of polygon edges.- Parameters:
line
- theLineString
to add
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setCheckRingsValid
public void setCheckRingsValid(boolean isCheckingRingsValid)
Allows disabling the valid ring checking, to optimize situations where invalid rings are not expected.The default is
true
.- Parameters:
isCheckingRingsValid
- true if generated rings should be checked for validity
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getPolygons
public java.util.Collection getPolygons()
Gets the list of polygons formed by the polygonization.- Returns:
- a collection of
Polygon
s
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getGeometry
public Geometry getGeometry()
Gets a geometry representing the polygons formed by the polygonization. If a valid polygonal geometry was extracted the result is aPolygonal
geometry.- Returns:
- a geometry containing the polygons
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getDangles
public java.util.Collection getDangles()
Gets the list of dangling lines found during polygonization.- Returns:
- a collection of the input
LineString
s which are dangles
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getCutEdges
public java.util.Collection getCutEdges()
Gets the list of cut edges found during polygonization.- Returns:
- a collection of the input
LineString
s which are cut edges
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getInvalidRingLines
public java.util.Collection getInvalidRingLines()
Gets the list of lines forming invalid rings found during polygonization.- Returns:
- a collection of the input
LineString
s which form invalid rings
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polygonize
private void polygonize()
Performs the polygonization, if it has not already been carried out.
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findValidRings
private void findValidRings(java.util.List edgeRingList, java.util.List validEdgeRingList, java.util.List invalidRingList)
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findShellsAndHoles
private void findShellsAndHoles(java.util.List edgeRingList)
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assignHolesToShells
private static void assignHolesToShells(java.util.List holeList, java.util.List shellList)
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assignHoleToShell
private static void assignHoleToShell(EdgeRing holeER, java.util.List shellList)
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findDisjointShells
private static void findDisjointShells(java.util.List shellList)
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findOuterShells
private static void findOuterShells(java.util.List shellList)
For each outer hole finds and includes a single outer shell. This seeds the traversal algorithm for finding only polygonal shells.- Parameters:
shellList
- the list of shell EdgeRings
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extractPolygons
private static java.util.List extractPolygons(java.util.List shellList, boolean includeAll)
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