Class NodingIntersectionFinder

java.lang.Object
org.locationtech.jts.noding.NodingIntersectionFinder
All Implemented Interfaces:
SegmentIntersector
public class NodingIntersectionFinder extends Object implements SegmentIntersector
Finds non-noded intersections in a set of SegmentStrings, if any exist.

Non-noded intersections include:

  • Interior intersections which lie in the interior of a segment (with another segment interior or with a vertex or endpoint)
  • Vertex intersections which occur at vertices in the interior of SegmentStrings (with a segment string endpoint or with another interior vertex)
The finder can be limited to finding only interior intersections by setting setInteriorIntersectionsOnly(boolean).

By default only the first intersection is found, but all can be found by setting setFindAllIntersections(boolean)

Version:
1.7

  • Constructor Details

    • NodingIntersectionFinder

      public NodingIntersectionFinder(LineIntersector li)
      Creates an intersection finder which finds an intersection if one exists
      Parameters:
      li - the LineIntersector to use

  • Method Details

    • createAnyIntersectionFinder

      public static NodingIntersectionFinder createAnyIntersectionFinder(LineIntersector li)
      Creates a finder which tests if there is at least one intersection. Uses short-circuiting for efficient performance. The intersection found is recorded.
      Parameters:
      li - a line intersector
      Returns:
      a finder which tests if there is at least one intersection.

    • createAllIntersectionsFinder

      public static NodingIntersectionFinder createAllIntersectionsFinder(LineIntersector li)
      Creates a finder which finds all intersections. The intersections are recorded for later inspection.
      Parameters:
      li - a line intersector
      Returns:
      a finder which finds all intersections.

    • createInteriorIntersectionsFinder

      public static NodingIntersectionFinder createInteriorIntersectionsFinder(LineIntersector li)
      Creates a finder which finds all interior intersections. The intersections are recorded for later inspection.
      Parameters:
      li - a line intersector
      Returns:
      a finder which finds all interior intersections.

    • createIntersectionCounter

      public static NodingIntersectionFinder createIntersectionCounter(LineIntersector li)
      Creates an finder which counts all intersections. The intersections are note recorded to reduce memory usage.
      Parameters:
      li - a line intersector
      Returns:
      a finder which counts all intersections.

    • createInteriorIntersectionCounter

      public static NodingIntersectionFinder createInteriorIntersectionCounter(LineIntersector li)
      Creates an finder which counts all interior intersections. The intersections are note recorded to reduce memory usage.
      Parameters:
      li - a line intersector
      Returns:
      a finder which counts all interior intersections.

    • setFindAllIntersections

      public void setFindAllIntersections(boolean findAllIntersections)
      Sets whether all intersections should be computed. When this is false (the default value) the value of isDone() is true after the first intersection is found.

      Default is false.

      Parameters:
      findAllIntersections - whether all intersections should be computed

    • setInteriorIntersectionsOnly

      public void setInteriorIntersectionsOnly(boolean isInteriorIntersectionsOnly)
      Sets whether only interior (proper) intersections will be found.
      Parameters:
      isInteriorIntersectionsOnly - whether to find only interior intersections

    • setCheckEndSegmentsOnly

      public void setCheckEndSegmentsOnly(boolean isCheckEndSegmentsOnly)
      Sets whether only end segments should be tested for intersection. This is a performance optimization that may be used if the segments have been previously noded by an appropriate algorithm. It may be known that any potential noding failures will occur only in end segments.
      Parameters:
      isCheckEndSegmentsOnly - whether to test only end segments

    • setKeepIntersections

      public void setKeepIntersections(boolean keepIntersections)
      Sets whether intersection points are recorded. If the only need is to count intersection points, this can be set to false.

      Default is true.

      Parameters:
      keepIntersections - indicates whether intersections should be recorded

    • getIntersections

      public List getIntersections()
      Gets the intersections found.
      Returns:
      a List of Coordinate

    • count

      public int count()
      Gets the count of intersections found.
      Returns:
      the intersection count

    • hasIntersection

      public boolean hasIntersection()
      Tests whether an intersection was found.
      Returns:
      true if an intersection was found

    • getIntersection

      public Coordinate getIntersection()
      Gets the computed location of the intersection. Due to round-off, the location may not be exact.
      Returns:
      the coordinate for the intersection location

    • getIntersectionSegments

      public Coordinate[] getIntersectionSegments()
      Gets the endpoints of the intersecting segments.
      Returns:
      an array of the segment endpoints (p00, p01, p10, p11)

    • processIntersections

      public void processIntersections(SegmentString e0, int segIndex0, SegmentString e1, int segIndex1)
      This method is called by clients of the SegmentIntersector class to process intersections for two segments of the SegmentStrings being intersected. Note that some clients (such as MonotoneChains) may optimize away this call for segment pairs which they have determined do not intersect (e.g. by an disjoint envelope test).
      Specified by:
      processIntersections in interface SegmentIntersector

    • isDone

      public boolean isDone()
      Description copied from interface: SegmentIntersector
      Reports whether the client of this class needs to continue testing all intersections in an arrangement.
      Specified by:
      isDone in interface SegmentIntersector
      Returns:
      true if there is no need to continue testing segments