Package org.locationtech.jtsexample.technique

Class SearchUsingPreparedGeometryIndex

java.lang.Object

org.locationtech.jtsexample.technique.SearchUsingPreparedGeometryIndex

public class SearchUsingPreparedGeometryIndex
extends Object

Demonstrates use of PreparedGeometrys in a spatial index to optimize spatial search. The example creates a grid of circular polygons, packed into the 1 x 1 square. This set of polygons is spatially indexed as PreparedGeometrys in an STRtree index. A series of random points in the square is generated, and the index is used to determine whether each point intersects any circles. The fraction of points which intersect will approximate the fraction of area covered by the circles.

Version:

1.12

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static GeometryFactory	geomFact
(package private) static final int	GRID_SIZE
(package private) static final int	MAX_ITER
(package private) static final int	POLYGON_SIZE

Constructor Summary

Constructors

Constructor	Description
SearchUsingPreparedGeometryIndex()

Method Summary

Modifier and Type	Method	Description
(package private) static double	area(Collection geoms)
(package private) static Geometry	createCircle(Coordinate centre, double radius)
(package private) static List	createCircleGrid(int gridSize)
(package private) static Point	createRandomPoint()
(package private) static List	findIntersecting(Collection targetGeoms, Geometry queryGeom)
static void	main(String[] args)
(package private) static int	runBruteForceQuery(Collection geoms)
(package private) static int	runIndexedQuery(PreparedGeometryIndex pgIndex)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

geomFact

static GeometryFactory geomFact

MAX_ITER

static final int MAX_ITER

See Also:

• Constant Field Values

GRID_SIZE

static final int GRID_SIZE

See Also:

• Constant Field Values

POLYGON_SIZE

static final int POLYGON_SIZE

See Also:

• Constant Field Values

Constructor Details

SearchUsingPreparedGeometryIndex

public SearchUsingPreparedGeometryIndex()

Method Details

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception

runIndexedQuery

static int runIndexedQuery(PreparedGeometryIndex pgIndex)

runBruteForceQuery

static int runBruteForceQuery(Collection geoms)

area

static double area(Collection geoms)

createCircleGrid

static List createCircleGrid(int gridSize)

createCircle

static Geometry createCircle(Coordinate centre,
 double radius)

createRandomPoint

static Point createRandomPoint()

findIntersecting

static List findIntersecting(Collection targetGeoms,
 Geometry queryGeom)