com.vividsolutions.jts.geomgraph

Class Label


public class Label
extends java.lang.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:
1.6

Constructor Summary

Label(Label lbl)
Construct a Label with the same values as the argument Label.
Label(int onLoc)
Construct a Label with a single location for both Geometries.
Label(int geomIndex, TopologyLocation gl)
Construct a Label with the same values as the argument for the given Geometry index.
Label(int geomIndex, int onLoc)
Construct a Label with a single location for both Geometries.
Label(int onLoc, int leftLoc, int rightLoc)
Construct a Label with On, Left and Right locations for both Geometries.
Label(int geomIndex, int onLoc, int leftLoc, int rightLoc)
Construct a Label with On, Left and Right locations for both Geometries.

Method Summary

boolean
allPositionsEqual(int geomIndex, int loc)
void
flip()
int
getGeometryCount()
int
getLocation(int geomIndex)
int
getLocation(int geomIndex, int posIndex)
boolean
isAnyNull(int geomIndex)
boolean
isArea()
boolean
isArea(int geomIndex)
boolean
isEqualOnSide(Label lbl, int side)
boolean
isLine(int geomIndex)
boolean
isNull(int geomIndex)
void
merge(Label lbl)
Merge this label with another one.
void
setAllLocations(int geomIndex, int location)
void
setAllLocationsIfNull(int location)
void
setAllLocationsIfNull(int geomIndex, int location)
void
setLocation(int geomIndex, int location)
void
setLocation(int geomIndex, int posIndex, int location)
void
toLine(int geomIndex)
Converts one GeometryLocation to a Line location
static Label
toLineLabel(Label label)
String
toString()

Constructor Details

Label

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

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,
             TopologyLocation gl)
Construct a Label with the same values as the argument for the given Geometry index.

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.

Method Details

allPositionsEqual

public boolean allPositionsEqual(int geomIndex,
                                 int loc)

flip

public void flip()

getGeometryCount

public int getGeometryCount()

getLocation

public int getLocation(int geomIndex)

getLocation

public int getLocation(int geomIndex,
                       int posIndex)

isAnyNull

public boolean isAnyNull(int geomIndex)

isArea

public boolean isArea()

isArea

public boolean isArea(int geomIndex)

isEqualOnSide

public boolean isEqualOnSide(Label lbl,
                             int side)

isLine

public boolean isLine(int geomIndex)

isNull

public boolean isNull(int geomIndex)

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

setAllLocations

public void setAllLocations(int geomIndex,
                            int location)

setAllLocationsIfNull

public void setAllLocationsIfNull(int location)

setAllLocationsIfNull

public void setAllLocationsIfNull(int geomIndex,
                                  int location)

setLocation

public void setLocation(int geomIndex,
                        int location)

setLocation

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

toLine

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

toLineLabel

public static Label toLineLabel(Label label)

toString

public String toString()