Examples of MonotoneChain

com.vividsolutions.jts.index.chain.MonotoneChain

Monotone Chains are a way of partitioning the segments of a linestring to allow for fast searching of intersections. They have the following properties:

the segments within a monotone chain never intersect each other
the envelope of any contiguous subset of the segments in a monotone chain is equal to the envelope of the endpoints of the subset.

Property 1 means that there is no need to test pairs of segments from within the same monotone chain for intersection.

Property 2 allows an efficient binary search to be used to find the intersection points of two monotone chains. For many types of real-world data, these properties eliminate a large number of segment comparisons, producing substantial speed gains.

One of the goals of this implementation of MonotoneChains is to be as space and time efficient as possible. One design choice that aids this is that a MonotoneChain is based on a subarray of a list of points. This means that new arrays of points (potentially very large) do not have to be allocated.

MonotoneChains support the following kinds of queries:

Envelope select: determine all the segments in the chain which intersect a given envelope
Overlap: determine all the pairs of segments in two chains whose envelopes overlap

This implementation of MonotoneChains uses the concept of internal iterators to return the resultsets for the above queries. This has time and space advantages, since it is not necessary to build lists of instantiated objects to represent the segments returned by the query. However, it does mean that the queries are not thread-safe. @version 1.7

org.apache.commons.math3.geometry.euclidean.twod.hull.MonotoneChain

books.org/wiki/Algorithm_Implementation/Geometry/Convex_hull/Monotone_chain"> Andrew's monotone chain algorithm (Wikibooks) @since 3.3

    final Envelope pixelEnv = hotPixel.getSafeEnvelope();
    final HotPixelSnapAction hotPixelSnapAction = new HotPixelSnapAction(hotPixel, parentEdge, hotPixelVertexIndex);


    index.query(pixelEnv, new ItemVisitor() {
      public void visitItem(Object item) {
        MonotoneChain testChain = (MonotoneChain) item;
        testChain.select(pixelEnv, hotPixelSnapAction);
      }
    }
    );
    return hotPixelSnapAction.isNodeAdded();
  }

                pointSet.addChild(node);
            }


            canvas.getLayer().addChild(pointSet);


            ConvexHullGenerator2D generator = new MonotoneChain(true, 1e-6);
            ConvexHull2D hull = generator.generate(points); //AklToussaintHeuristic.reducePoints(points));


            PNode hullNode = new PNode();
            for (Vector2D vertex : hull.getVertices()) {
                final PPath node = PPath.createEllipse(vertex.getX() - 1, vertex.getY() - 1, 2, 2);
                node.addAttribute("tooltip", vertex);

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Examples of MonotoneChain

Examples of com.vividsolutions.jts.index.chain.MonotoneChain

Examples of org.apache.commons.math3.geometry.euclidean.twod.hull.MonotoneChain