geotools的空间索引使用——R树和四叉树

点索引可以用网格索引kdtree

线和面的索引用strtree或者QuadTree

/**
 * 空间索引之st R树
 */
public static void stRTreeTest(){
    String filePath = "E:\gis资料\测试数据\道路中心线.shp";
    SimpleFeatureCollection sfc = fromShapeFile(filePath);
    SimpleFeatureIterator iterator = sfc.features();
    STRtree stRtree = new STRtree(sfc.size());
    while (iterator.hasNext()){
        Feature ft = iterator.next();
        MultiLineString multiLineString = (MultiLineString)((SimpleFeature) ft).getDefaultGeometry();
        stRtree.insert(multiLineString.getEnvelopeInternal(),ft);
    }
    System.out.println("str树深度："+stRtree.depth());
    stRtree.build();
    System.out.println("str树深度："+stRtree.getRoot().getLevel());
    GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();

    Geometry point =  geometryFactory.createPoint(new Coordinate(120.68,30.76));
    Envelope search = new Envelope(point.getCoordinate());
    search.expandBy(0.001);
    Date start = new Date();
    List result = stRtree.query(search);

   // MySizeOf.sizeOf(stRtree);
    System.out.println("总数据量:"+stRtree.size()+"条");
    System.out.println("查询结果："+result.size()+"条");
    System.out.println("STR树索引查找耗时:"+(new Date().getTime() - start.getTime()));
}

/**
 * 空间索引之st 四叉树
 * 点索引使用kdtree最好
 */
public static void QuadtreeTest(){
    String filePath = "E:\gis资料\测试数据\道路中心线.shp";
    SimpleFeatureCollection sfc = fromShapeFile(filePath);
    SimpleFeatureIterator iterator = sfc.features();

    GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();
    Geometry point =  geometryFactory.createPoint(new Coordinate(120.68,30.76));
    Quadtree quadtree = new Quadtree();
    Date start = new Date();
    while (iterator.hasNext()){
        Feature ft = iterator.next();
        MultiLineString multiLineString = (MultiLineString)((SimpleFeature) ft).getDefaultGeometry();
        /*if(multiLineString.intersects(point)){
            break;
        }*/
        quadtree.insert(multiLineString.getEnvelopeInternal(),ft);
    }

    System.out.println("无索引查找耗时:"+(new Date().getTime() - start.getTime()));


    start = new Date();
    Envelope search = new Envelope(point.getCoordinate());
    OctagonalEnvelope searchGeom = new OctagonalEnvelope(point.getCoordinate());
    searchGeom.expandBy(0.001);
    search.expandBy(0.001);

    List result = quadtree.query(search);
    System.out.println(result.get(0).getClass());
    List lastRs = new ArrayList();
    for(Object ob : result){
        SimpleFeature sft = (SimpleFeature)ob;
        Geometry lineGeom =  (Geometry)sft.getDefaultGeometry();
        if(lineGeom.intersects(searchGeom.toGeometry(geometryFactory))){
            lastRs.add(ob);
        }
    }
    System.out.println("总数据量:"+quadtree.size()+"条");
    System.out.println("查询结果："+lastRs.size()+"条");
    System.out.println("四叉树深度："+quadtree.depth());
    System.out.println("四叉树树索引查找耗时:"+(new Date().getTime() - start.getTime()));
}

总数据量:67749条

查询结果：8条

STR树索引查找耗时:29

查询结果：8条

四叉树深度：28

四叉树树索引查找耗时:35