Package org.locationtech.jts.operation.linemerge

Class LineMerger

  • public class LineMerger
extends java.lang.Object
    Merges a collection of linear components to form maximal-length linestrings.

    Merging stops at nodes of degree 1 or degree 3 or more. In other words, all nodes of degree 2 are merged together. The exception is in the case of an isolated loop, which only has degree-2 nodes. In this case one of the nodes is chosen as a starting point.

    The direction of each merged LineString will be that of the majority of the LineStrings from which it was derived.

    Any dimension of Geometry is handled - the constituent linework is extracted to form the edges. The edges must be correctly noded; that is, they must only meet at their endpoints. The LineMerger will accept non-noded input but will not merge non-noded edges.

    Input lines which are empty or contain only a single unique coordinate are not included in the merging.

    Version:
    1.7

    • Field Detail

      • mergedLineStrings

        private java.util.Collection mergedLineStrings

      • edgeStrings

        private java.util.Collection edgeStrings

    • Constructor Detail

      • LineMerger

        public LineMerger()
        Creates a new line merger.

    • Method Detail

      • add

        public void add​(Geometry geometry)
        Adds a Geometry to be processed. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted.
        Parameters:
        geometry - geometry to be line-merged

      • add

        public void add​(java.util.Collection geometries)
        Adds a collection of Geometries to be processed. May be called multiple times. Any dimension of Geometry may be added; the constituent linework will be extracted.
        Parameters:
        geometries - the geometries to be line-merged

      • add

        private void add​(LineString lineString)

      • merge

        private void merge()

      • buildEdgeStringsForObviousStartNodes

        private void buildEdgeStringsForObviousStartNodes()

      • buildEdgeStringsForIsolatedLoops

        private void buildEdgeStringsForIsolatedLoops()

      • buildEdgeStringsForUnprocessedNodes

        private void buildEdgeStringsForUnprocessedNodes()

      • buildEdgeStringsForNonDegree2Nodes

        private void buildEdgeStringsForNonDegree2Nodes()

      • buildEdgeStringsStartingAt

        private void buildEdgeStringsStartingAt​(Node node)

      • getMergedLineStrings

        public java.util.Collection getMergedLineStrings()
        Gets the LineStrings created by the merging process.
        Returns:
        the collection of merged LineStrings