Class CoverageUnion
- java.lang.Object
-
- org.locationtech.jts.operation.overlayng.CoverageUnion
-
public class CoverageUnion extends java.lang.Object
Unions a valid coverage of polygons or lines in an efficient way.A polygonal coverage is a collection of
Polygon
s which satisfy the following conditions:- Vector-clean - Line segments within the collection must either be identical or intersect only at endpoints.
- Non-overlapping - No two polygons may overlap. Equivalently, polygons must be interior-disjoint.
A linear coverage is a collection of
LineString
s which satisfies the Vector-clean condition. Note that this does not require the LineStrings to be fully noded - i.e. they may contain coincident linework. Coincident line segments are dissolved by the union. Currently linear output is not merged (this may be added in a future release.)No checking is done to determine whether the input is a valid coverage. This is because coverage validation involves segment intersection detection, which is much more expensive than the union phase. If the input is not a valid coverage then in some cases this will be detected during processing and a
TopologyException
is thrown. Otherwise, the computation will produce output, but it will be invalid.Unioning a valid coverage implies that no new vertices are created. This means that a precision model does not need to be specified. The precision of the vertices in the output geometry is not changed.
- Author:
- Martin Davis
- See Also:
BoundaryChainNoder
,SegmentExtractingNoder
-
-
Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static Geometry
union(Geometry coverage)
Unions a valid polygonal coverage or linear network.
-
-
-
Method Detail
-
union
public static Geometry union(Geometry coverage)
Unions a valid polygonal coverage or linear network.- Parameters:
coverage
- a coverage of polygons or lines- Returns:
- the union of the coverage
- Throws:
TopologyException
- in some cases if the coverage is invalid
-
-