Package org.locationtech.jts.noding.snapround

Class MCIndexSnapRounder

  • All Implemented Interfaces:
    Noder
    public class MCIndexSnapRounder
extends java.lang.Object
implements Noder
    Uses Snap Rounding to compute a rounded, fully noded arrangement from a set of SegmentStrings. Implements the Snap Rounding technique described in papers by Hobby, Guibas & Marimont, and Goodrich et al. Snap Rounding assumes that all vertices lie on a uniform grid; hence the precision model of the input must be fixed precision, and all the input vertices must be rounded to that precision.

    This implementation uses a monotone chains and a spatial index to speed up the intersection tests.

    This implementation appears to be fully robust using an integer precision model. It will function with non-integer precision models, but the results are not 100% guaranteed to be correctly noded.

    Version:
    1.7

    • Constructor Detail

      • MCIndexSnapRounder

        public MCIndexSnapRounder​(PrecisionModel pm)

    • Method Detail

      • getNodedSubstrings

        public java.util.Collection getNodedSubstrings()
        Description copied from interface: Noder
        Returns a Collection of fully noded SegmentStrings. The SegmentStrings have the same context as their parent.
        Specified by:
        getNodedSubstrings in interface Noder
        Returns:
        a Collection of SegmentStrings

      • computeNodes

        public void computeNodes​(java.util.Collection inputSegmentStrings)
        Description copied from interface: Noder
        Computes the noding for a collection of SegmentStrings. Some Noders may add all these nodes to the input SegmentStrings; others may only add some or none at all.
        Specified by:
        computeNodes in interface Noder
        Parameters:
        inputSegmentStrings - a collection of SegmentStrings to node

      • checkCorrectness

        private void checkCorrectness​(java.util.Collection inputSegmentStrings)

      • snapRound

        private void snapRound​(java.util.Collection segStrings,
                       LineIntersector li)

      • findInteriorIntersections

        private java.util.List findInteriorIntersections​(java.util.Collection segStrings,
                                                 LineIntersector li)
        Computes all interior intersections in the collection of SegmentStrings, and returns their Coordinates. Does NOT node the segStrings.
        Returns:
        a list of Coordinates for the intersections

      • computeIntersectionSnaps

        private void computeIntersectionSnaps​(java.util.Collection snapPts)
        Snaps segments to nodes created by segment intersections.

      • computeVertexSnaps

        public void computeVertexSnaps​(java.util.Collection edges)
        Snaps segments to all vertices.
        Parameters:
        edges - the list of segment strings to snap together

      • computeVertexSnaps

        private void computeVertexSnaps​(NodedSegmentString e)
        Snaps segments to the vertices of a Segment String.