org.apache.lucene.document

Class LatLonPoint

java.lang.Object

org.apache.lucene.document.Field

org.apache.lucene.document.LatLonPoint

All Implemented Interfaces:

IndexableField

public class LatLonPoint
extends Field

An indexed location field.

Finding all documents within a range at search time is efficient. Multiple values for the same field in one document is allowed.

This field defines static factory methods for common operations:

• newBoxQuery() for matching points within a bounding box.
• newDistanceQuery() for matching points within a specified distance.
• newPolygonQuery() for matching points within an arbitrary polygon.
• nearest() for finding the k-nearest neighbors by distance.

If you also need per-document operations such as sort by distance, add a separate LatLonDocValuesField instance. If you also need to store the value, you should add a separate StoredField instance.

WARNING: Values are indexed with some loss of precision from the original double values (4.190951585769653E-8 for the latitude component and 8.381903171539307E-8 for longitude).

See Also:

PointValues, LatLonDocValuesField

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.document.Field

Field.Store

Field Summary

Fields

Modifier and Type	Field and Description
static int	BYTES LatLonPoint is encoded as integer values so number of bytes is 4
static FieldType	TYPE Type for an indexed LatLonPoint

Fields inherited from class org.apache.lucene.document.Field

fieldsData, name, tokenStream, type

Constructor Summary

Constructors

Constructor and Description
LatLonPoint(String name, double latitude, double longitude) Creates a new LatLonPoint with the specified latitude and longitude

Method Summary

Modifier and Type	Method and Description
static TopFieldDocs	nearest(IndexSearcher searcher, String field, double latitude, double longitude, int n) Finds the n nearest indexed points to the provided point, according to Haversine distance.
static Query	newBoxQuery(String field, double minLatitude, double maxLatitude, double minLongitude, double maxLongitude) Create a query for matching a bounding box.
static Query	newDistanceQuery(String field, double latitude, double longitude, double radiusMeters) Create a query for matching points within the specified distance of the supplied location.
static Query	newPolygonQuery(String field, Polygon... polygons) Create a query for matching one or more polygons.
void	setLocationValue(double latitude, double longitude) Change the values of this field
String	toString()

Methods inherited from class org.apache.lucene.document.Field

binaryValue, fieldType, name, numericValue, readerValue, setBytesValue, setBytesValue, setByteValue, setDoubleValue, setFloatValue, setIntValue, setLongValue, setReaderValue, setShortValue, setStringValue, setTokenStream, stringValue, tokenStream, tokenStreamValue

Methods inherited from class java.lang.Object

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

Field Detail

BYTES

public static final int BYTES

LatLonPoint is encoded as integer values so number of bytes is 4

See Also:

Constant Field Values

TYPE

public static final FieldType TYPE

Type for an indexed LatLonPoint

Each point stores two dimensions with 4 bytes per dimension.

Constructor Detail

LatLonPoint

public LatLonPoint(String name,
                   double latitude,
                   double longitude)

Creates a new LatLonPoint with the specified latitude and longitude

Parameters:

name - field name

latitude - latitude value: must be within standard +/-90 coordinate bounds.

longitude - longitude value: must be within standard +/-180 coordinate bounds.

Throws:

IllegalArgumentException - if the field name is null or latitude or longitude are out of bounds

Method Detail

setLocationValue

public void setLocationValue(double latitude,
                             double longitude)

Change the values of this field

Parameters:

latitude - latitude value: must be within standard +/-90 coordinate bounds.

longitude - longitude value: must be within standard +/-180 coordinate bounds.

Throws:

IllegalArgumentException - if latitude or longitude are out of bounds

toString

public String toString()

Overrides:

toString in class Field

newBoxQuery

public static Query newBoxQuery(String field,
                                double minLatitude,
                                double maxLatitude,
                                double minLongitude,
                                double maxLongitude)

Create a query for matching a bounding box.

The box may cross over the dateline.

Parameters:

field - field name. must not be null.

minLatitude - latitude lower bound: must be within standard +/-90 coordinate bounds.

maxLatitude - latitude upper bound: must be within standard +/-90 coordinate bounds.

minLongitude - longitude lower bound: must be within standard +/-180 coordinate bounds.

maxLongitude - longitude upper bound: must be within standard +/-180 coordinate bounds.

Returns:

query matching points within this box

Throws:

IllegalArgumentException - if field is null, or the box has invalid coordinates.

newDistanceQuery

public static Query newDistanceQuery(String field,
                                     double latitude,
                                     double longitude,
                                     double radiusMeters)

Create a query for matching points within the specified distance of the supplied location.

Parameters:

field - field name. must not be null.

latitude - latitude at the center: must be within standard +/-90 coordinate bounds.

longitude - longitude at the center: must be within standard +/-180 coordinate bounds.

radiusMeters - maximum distance from the center in meters: must be non-negative and finite.

Returns:

query matching points within this distance

Throws:

IllegalArgumentException - if field is null, location has invalid coordinates, or radius is invalid.

newPolygonQuery

public static Query newPolygonQuery(String field,
                                    Polygon... polygons)

Create a query for matching one or more polygons.

Parameters:

field - field name. must not be null.

polygons - array of polygons. must not be null or empty

Returns:

query matching points within this polygon

Throws:

IllegalArgumentException - if field is null, polygons is null or empty

See Also:

Polygon

nearest

public static TopFieldDocs nearest(IndexSearcher searcher,
                                   String field,
                                   double latitude,
                                   double longitude,
                                   int n)
                            throws IOException

Finds the n nearest indexed points to the provided point, according to Haversine distance.

This is functionally equivalent to running MatchAllDocsQuery with a LatLonDocValuesField.newDistanceSort(java.lang.String, double, double), but is far more efficient since it takes advantage of properties the indexed BKD tree. Currently this only works with Lucene60PointsFormat (used by the default codec). Multi-valued fields are currently not de-duplicated, so if a document had multiple instances of the specified field that make it into the top n, that document will appear more than once.

Documents are ordered by ascending distance from the location. The value returned in FieldDoc for the hits contains a Double instance with the distance in meters.

Parameters:

searcher - IndexSearcher to find nearest points from.

field - field name. must not be null.

latitude - latitude at the center: must be within standard +/-90 coordinate bounds.

longitude - longitude at the center: must be within standard +/-180 coordinate bounds.

n - the number of nearest neighbors to retrieve.

Returns:

TopFieldDocs containing documents ordered by distance, where the field value for each FieldDoc is the distance in meters

Throws:

IllegalArgumentException - if the underlying PointValues is not a Lucene60PointsReader (this is a current limitation), or if field or searcher is null, or if latitude, longitude or n are out-of-bounds

IOException - if an IOException occurs while finding the points.