Package org.meteoinfo.jts.operation.polygonize

Class Polygonizer


  • public class Polygonizer
extends java.lang.Object
    Polygonizes a set of Geometrys 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)
    Polygonization supports extracting only polygons which form a valid polygonal geometry. The set of extracted polygons is guaranteed to be edge-disjoint. This is useful for situations where it is known that the input lines form a valid polygonal geometry.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected java.util.List cutEdges  
      protected java.util.Collection dangles  
      protected org.meteoinfo.jts.operation.polygonize.PolygonizeGraph graph  
      protected java.util.List holeList  
      protected java.util.List invalidRingLines  
      protected java.util.List polyList  
      protected java.util.List shellList  

    • Constructor Summary

      Constructors 
      Constructor Description
      Polygonizer​()
      Creates a polygonizer with the same GeometryFactory as the input Geometrys.
      Polygonizer​(boolean extractOnlyPolygonal)
      Creates a polygonizer and allow specifyng if only polygons which form a valid polygonal geometry are to be extracted.

    • Method Summary

      All 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 a Geometry to the edges to be polygonized.
      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.
      void setCheckRingsValid​(boolean isCheckingRingsValid)
      Allows disabling the valid ring checking, to optimize situations where invalid rings are not expected.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • graph

        protected org.meteoinfo.jts.operation.polygonize.PolygonizeGraph graph

      • dangles

        protected java.util.Collection dangles

      • cutEdges

        protected java.util.List cutEdges

      • invalidRingLines

        protected java.util.List invalidRingLines

      • holeList

        protected java.util.List holeList

      • shellList

        protected java.util.List shellList

      • polyList

        protected java.util.List polyList

    • Constructor Detail

      • Polygonizer

        public Polygonizer​()
        Creates a polygonizer with the same GeometryFactory as the input Geometrys. The output mask is #ALL_POLYS.

      • Polygonizer

        public Polygonizer​(boolean extractOnlyPolygonal)
        Creates a polygonizer and allow specifyng 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

    • Method Detail

      • 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 of Geometrys with linework to be polygonized

      • add

        public void add​(Geometry g)
        Add a Geometry 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 - a Geometry with linework to be polygonized

      • 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

      • getPolygons

        public java.util.Collection getPolygons​()
        Gets the list of polygons formed by the polygonization.
        Returns:
        a collection of Polygons

      • getGeometry

        public Geometry getGeometry​()
        Gets a geometry representing the polygons formed by the polygonization. If a valid polygonal geometry was extracted the result is a geometry.
        Returns:
        a geometry containing the polygons

      • getDangles

        public java.util.Collection getDangles​()
        Gets the list of dangling lines found during polygonization.
        Returns:
        a collection of the input LineStrings which are dangles

      • getCutEdges

        public java.util.Collection getCutEdges​()
        Gets the list of cut edges found during polygonization.
        Returns:
        a collection of the input LineStrings which are cut edges

      • getInvalidRingLines

        public java.util.Collection getInvalidRingLines​()
        Gets the list of lines forming invalid rings found during polygonization.
        Returns:
        a collection of the input LineStrings which form invalid rings