org.apache.lucene.spatial.geopoint.search

Class GeoPointDistanceQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.spatial.geopoint.search.GeoPointInBBoxQuery

org.apache.lucene.spatial.geopoint.search.GeoPointDistanceQuery

All Implemented Interfaces:

Cloneable

Direct Known Subclasses:

GeoPointDistanceRangeQuery

public class GeoPointDistanceQuery
extends GeoPointInBBoxQuery

Implements a simple point distance query on a GeoPoint field. This is based on GeoPointInBBoxQuery and is implemented using a two phase approach. First, like GeoPointInBBoxQueryImpl candidate terms are queried using the numeric ranges based on the morton codes of the min and max lat/lon pairs that intersect the boundary of the point-radius circle. Terms passing this initial filter are then passed to a secondary postFilter method that verifies whether the decoded lat/lon point fall within the specified query distance (see SloppyMath.haversin(double, double, double, double). All morton value comparisons are subject to the same precision tolerance defined in 1.0E-6 and distance comparisons are subject to the accuracy of the haversine formula (from R.W. Sinnott, "Virtues of the Haversine", Sky and Telescope, vol. 68, no. 2, 1984, p. 159)

Note: This query currently uses haversine which is a sloppy distance calculation (see above reference). For large queries one can expect upwards of 400m error. Vincenty shrinks this to ~40m error but pays a penalty for computing using the spheroid

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

Fields

Modifier and Type	Field and Description
protected double	centerLat latitude value (in degrees) for query location
protected double	centerLon longitude value (in degrees) for query location
protected double	radiusMeters distance (in meters) from lon, lat center location

Fields inherited from class org.apache.lucene.spatial.geopoint.search.GeoPointInBBoxQuery

field, maxLat, maxLon, minLat, minLon, termEncoding

Constructor Summary

Constructors

Constructor and Description
GeoPointDistanceQuery(String field, double centerLon, double centerLat, double radiusMeters) Constructs a Query for all GeoPointField types within a distance (in meters) from a given point
GeoPointDistanceQuery(String field, GeoPointField.TermEncoding termEncoding, double centerLon, double centerLat, double radiusMeters)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object o)
double	getCenterLat() getter method for center latitude value
double	getCenterLon() getter method for center longitude value
double	getRadiusMeters() getter method for distance value (in meters)
int	hashCode()
Query	rewrite(IndexReader reader)
String	toString(String field)

Methods inherited from class org.apache.lucene.spatial.geopoint.search.GeoPointInBBoxQuery

getField, getMaxLat, getMaxLon, getMinLat, getMinLon

Methods inherited from class org.apache.lucene.search.Query

clone, createWeight, getBoost, setBoost, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

centerLon

protected final double centerLon

longitude value (in degrees) for query location

centerLat

protected final double centerLat

latitude value (in degrees) for query location

radiusMeters

protected final double radiusMeters

distance (in meters) from lon, lat center location

Constructor Detail

GeoPointDistanceQuery

public GeoPointDistanceQuery(String field,
                     double centerLon,
                     double centerLat,
                     double radiusMeters)

Constructs a Query for all GeoPointField types within a distance (in meters) from a given point

GeoPointDistanceQuery

public GeoPointDistanceQuery(String field,
                     GeoPointField.TermEncoding termEncoding,
                     double centerLon,
                     double centerLat,
                     double radiusMeters)

Method Detail

rewrite

public Query rewrite(IndexReader reader)
              throws IOException

Overrides:

rewrite in class GeoPointInBBoxQuery

Throws:

IOException

equals

public boolean equals(Object o)

Overrides:

equals in class GeoPointInBBoxQuery

hashCode

public int hashCode()

Overrides:

hashCode in class GeoPointInBBoxQuery

toString

public String toString(String field)

Overrides:

toString in class GeoPointInBBoxQuery

getCenterLon

public double getCenterLon()

getter method for center longitude value

getCenterLat

public double getCenterLat()

getter method for center latitude value

getRadiusMeters

public double getRadiusMeters()

getter method for distance value (in meters)