Label class
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
Constructors
- Label(int onLoc)
- Construct a Label with a single location for both Geometries. Initialize the locations to Null
- Label.args2(int geomIndex, int onLoc)
- Construct a Label with a single location for both Geometries. Initialize the location for the Geometry index.
- Label.args3(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.args4(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.fromLabel(Label lbl)
- Construct a Label with the same values as the argument Label.
Properties
-
elt
↔ List<
TopologyLocation?> -
getter/setter pair
- hashCode → int
-
The hash code for this object.
no setterinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
Methods
-
allPositionsEqual(
int geomIndex, int loc) → bool -
flip(
) → void -
getGeometryCount(
) → int -
getLocation(
int geomIndex) → int -
getLocationWithPosIndex(
int geomIndex, int posIndex) → int -
isAnyNull(
int geomIndex) → bool -
isArea(
) → bool -
isAreaWithIndex(
int geomIndex) → bool -
isEqualOnSide(
Label lbl, int side) → bool -
isLine(
int geomIndex) → bool -
isNull(
int geomIndex) → bool -
merge(
Label lbl) → void - Merge this label with another one. Merging updates any null attributes of this label with the attributes from lbl
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
setAllLocations(
int geomIndex, int location) → void -
setAllLocationsIfNull(
int location) → void -
setAllLocationsIfNullWithIndex(
int geomIndex, int location) → void -
setLocation(
int geomIndex, int posIndex, int location) → void -
setLocationWithIndex(
int geomIndex, int location) → void -
toLine(
int geomIndex) → void - Converts one GeometryLocation to a Line location
-
toString(
) → String -
A string representation of this object.
override
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited
Static Methods
-
toLineLabel(
Label label) → Label