Class Label

java.lang.Object
org.locationtech.jts.geomgraph.Label

public class Label extends Object
A Label indicates the topological relationship of a component of a topology graph to a given Geometry. This class supports labels for relationships to two Geometrys, which is sufficient for algorithms for binary operations.

Topology graphs support the concept of labeling nodes and edges in the graph. The label of a node or edge specifies its topological relationship to one or more geometries. (In fact, since JTS operations have only two arguments labels are required for only two geometries). A label for a node or edge has one or two elements, depending on whether the node or edge occurs in one or both of the input Geometrys. Elements contain attributes which categorize the topological location of the node or edge relative to the parent Geometry; that is, whether the node or edge is in the interior, boundary or exterior of the Geometry. Attributes have a value from the set {Interior, Boundary, Exterior}. In a node each element has a single attribute <On>. For an edge each element has a triplet of attributes <Left, On, Right>.

It is up to the client code to associate the 0 and 1 TopologyLocations with specific geometries.

Version:
1.7
  • Field Details

  • Constructor Details

    • Label

      public Label(int onLoc)
      Construct a Label with a single location for both Geometries. Initialize the locations to Null
    • Label

      public Label(int geomIndex, int onLoc)
      Construct a Label with a single location for both Geometries. Initialize the location for the Geometry index.
    • Label

      public Label(int onLoc, int leftLoc, int rightLoc)
      Construct a Label with On, Left and Right locations for both Geometries. Initialize the locations for both Geometries to the given values.
    • Label

      public Label(int geomIndex, int onLoc, int leftLoc, int rightLoc)
      Construct a Label with On, Left and Right locations for both Geometries. Initialize the locations for the given Geometry index.
    • Label

      public Label(Label lbl)
      Construct a Label with the same values as the argument Label.
  • Method Details

    • toLineLabel

      public static Label toLineLabel(Label label)
    • flip

      public void flip()
    • getLocation

      public int getLocation(int geomIndex, int posIndex)
    • getLocation

      public int getLocation(int geomIndex)
    • setLocation

      public void setLocation(int geomIndex, int posIndex, int location)
    • setLocation

      public void setLocation(int geomIndex, int location)
    • setAllLocations

      public void setAllLocations(int geomIndex, int location)
    • setAllLocationsIfNull

      public void setAllLocationsIfNull(int geomIndex, int location)
    • setAllLocationsIfNull

      public void setAllLocationsIfNull(int location)
    • merge

      public void merge(Label lbl)
      Merge this label with another one. Merging updates any null attributes of this label with the attributes from lbl
    • getGeometryCount

      public int getGeometryCount()
    • isNull

      public boolean isNull(int geomIndex)
    • isAnyNull

      public boolean isAnyNull(int geomIndex)
    • isArea

      public boolean isArea()
    • isArea

      public boolean isArea(int geomIndex)
    • isLine

      public boolean isLine(int geomIndex)
    • isEqualOnSide

      public boolean isEqualOnSide(Label lbl, int side)
    • allPositionsEqual

      public boolean allPositionsEqual(int geomIndex, int loc)
    • toLine

      public void toLine(int geomIndex)
      Converts one GeometryLocation to a Line location
    • toString

      public String toString()
      Overrides:
      toString in class Object