com.vividsolutions.jts.operation.union
Class UnaryUnionOp
java.lang.Object
com.vividsolutions.jts.operation.union.UnaryUnionOp
public class UnaryUnionOp
- extends java.lang.Object
Unions a collection of Geometry or a single Geometry
(which may be a collection) together.
By using this special-purpose operation over a collection of geometries
it is possible to take advantage of various optimizations to improve performance.
Heterogeneous GeometryCollection
s are fully supported.
The result obeys the following contract:
- Unioning a set of overlapping
Polygons
s has the effect of
merging the areas (i.e. the same effect as
iteratively unioning all individual polygons together).
- Unioning a set of
LineString
s has the effect of noding
and dissolving the input linework.
In this context "fully noded" means that there will be a node or endpoint in the result
for every endpoint or line segment crossing in the input.
"Dissolved" means that any duplicate (i.e. coincident) line segments or portions
of line segments will be reduced to a single line segment in the result.
This is consistent with the semantics of the
Geometry.union(Geometry)
operation.
If merged linework is required, the LineMerger
class can be used.
- Unioning a set of
Points
s has the effect of merging
all identical points (producing a set with no duplicates).
UnaryUnion always operates on the individual components of MultiGeometries.
So it is possible to use it to "clean" invalid self-intersecting MultiPolygons
(although the polygon components must all still be individually valid.)
- Author:
- mbdavis
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
UnaryUnionOp
public UnaryUnionOp(java.util.Collection geoms,
GeometryFactory geomFact)
UnaryUnionOp
public UnaryUnionOp(java.util.Collection geoms)
UnaryUnionOp
public UnaryUnionOp(Geometry geom)
union
public static Geometry union(java.util.Collection geoms)
union
public static Geometry union(java.util.Collection geoms,
GeometryFactory geomFact)
union
public static Geometry union(Geometry geom)
union
public Geometry union()
- Gets the union of the input geometries.
If no input geometries were provided, a POINT EMPTY is returned.
- Returns:
- a Geometry containing the union