org.apache.lucene.spatial.bbox

Class BBoxStrategy

java.lang.Object

org.apache.lucene.spatial.SpatialStrategy

org.apache.lucene.spatial.bbox.BBoxStrategy

public class BBoxStrategy
extends SpatialStrategy

A SpatialStrategy for indexing and searching Rectangles by storing its coordinates in numeric fields. It supports all SpatialOperations and has a custom overlap relevancy. It is based on GeoPortal's SpatialClauseAdapter.

Characteristics:

• Only indexes Rectangles; just one per field value. Other shapes can be provided and the bounding box will be used.
• Can query only by a Rectangle. Providing other shapes is an error.
• Supports most SpatialOperations but not Overlaps.
• Uses the DocValues API for any sorting / relevancy.

Implementation:

This uses 4 double fields for minX, maxX, minY, maxY and a boolean to mark a dateline cross. Depending on the particular SpatialOperations, there are a variety of range queries on DoublePoints to be done. The makeOverlapRatioValueSource(org.locationtech.spatial4j.shape.Rectangle, double) works by calculating the query bbox overlap percentage against the indexed shape overlap percentage. The indexed shape's coordinates are retrieved from LeafReader.getNumericDocValues(java.lang.String).

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

Field Summary

Fields

Modifier and Type	Field and Description
static FieldType	DEFAULT_FIELDTYPE pointValues, docValues, and nothing else.
static String	SUFFIX_MAXX
static String	SUFFIX_MAXY
static String	SUFFIX_MINX
static String	SUFFIX_MINY
static String	SUFFIX_XDL

Fields inherited from class org.apache.lucene.spatial.SpatialStrategy

ctx

Constructor Summary

Constructors

Constructor and Description
BBoxStrategy(org.locationtech.spatial4j.context.SpatialContext ctx, String fieldNamePrefix, FieldType fieldType) Creates this strategy.

Method Summary

Modifier and Type	Method and Description
Field[]	createIndexableFields(org.locationtech.spatial4j.shape.Shape shape) Returns the IndexableField(s) from the shape that are to be added to the Document.
FieldType	getFieldType() Returns a field type representing the set of field options.
DoubleValuesSource	makeDistanceValueSource(org.locationtech.spatial4j.shape.Point queryPoint, double multiplier) Make a ValueSource returning the distance between the center of the indexed shape and queryPoint.
DoubleValuesSource	makeOverlapRatioValueSource(org.locationtech.spatial4j.shape.Rectangle queryBox, double queryTargetProportion) Returns a similarity based on BBoxOverlapRatioValueSource.
Query	makeQuery(SpatialArgs args) Make a Query based principally on SpatialOperation and Shape from the supplied args.
ShapeValuesSource	makeShapeValueSource() Provides access to each rectangle per document as a ShapeValuesSource
static BBoxStrategy	newInstance(org.locationtech.spatial4j.context.SpatialContext ctx, String fieldNamePrefix) Creates a new BBoxStrategy instance that uses DoublePoint and DoublePoint.newRangeQuery(java.lang.String, double, double)

Methods inherited from class org.apache.lucene.spatial.SpatialStrategy

getFieldName, getSpatialContext, makeDistanceValueSource, makeRecipDistanceValueSource, toString

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_FIELDTYPE

public static FieldType DEFAULT_FIELDTYPE

pointValues, docValues, and nothing else.

SUFFIX_MINX

public static final String SUFFIX_MINX

See Also:

Constant Field Values

SUFFIX_MAXX

public static final String SUFFIX_MAXX

See Also:

Constant Field Values

SUFFIX_MINY

public static final String SUFFIX_MINY

See Also:

Constant Field Values

SUFFIX_MAXY

public static final String SUFFIX_MAXY

See Also:

Constant Field Values

SUFFIX_XDL

public static final String SUFFIX_XDL

See Also:

Constant Field Values

Constructor Detail

BBoxStrategy

public BBoxStrategy(org.locationtech.spatial4j.context.SpatialContext ctx,
                    String fieldNamePrefix,
                    FieldType fieldType)

Creates this strategy. fieldType is used to customize the indexing options of the 4 number fields, and to a lesser degree the XDL field too. Search requires pointValues (or legacy numerics), and relevancy requires docValues. If these features aren't needed then disable them.

Method Detail

newInstance

public static BBoxStrategy newInstance(org.locationtech.spatial4j.context.SpatialContext ctx,
                                       String fieldNamePrefix)

Creates a new BBoxStrategy instance that uses DoublePoint and DoublePoint.newRangeQuery(java.lang.String, double, double)

getFieldType

public FieldType getFieldType()

Returns a field type representing the set of field options. This is identical to what was passed into the constructor. It's frozen.

createIndexableFields

public Field[] createIndexableFields(org.locationtech.spatial4j.shape.Shape shape)

Description copied from class: SpatialStrategy

Returns the IndexableField(s) from the shape that are to be added to the Document. These fields are expected to be marked as indexed and not stored.

Note: If you want to store the shape as a string for retrieval in search results, you could add it like this:

document.add(new StoredField(fieldName,ctx.toString(shape)));

The particular string representation used doesn't matter to the Strategy since it doesn't use it.

Specified by:

createIndexableFields in class SpatialStrategy

Returns:

Not null nor will it have null elements.

makeShapeValueSource

public ShapeValuesSource makeShapeValueSource()

Provides access to each rectangle per document as a ShapeValuesSource

makeDistanceValueSource

public DoubleValuesSource makeDistanceValueSource(org.locationtech.spatial4j.shape.Point queryPoint,
                                                  double multiplier)

Description copied from class: SpatialStrategy

Make a ValueSource returning the distance between the center of the indexed shape and queryPoint. If there are multiple indexed shapes then the closest one is chosen. The result is multiplied by multiplier, which conveniently is used to get the desired units.

Specified by:

makeDistanceValueSource in class SpatialStrategy

makeOverlapRatioValueSource

public DoubleValuesSource makeOverlapRatioValueSource(org.locationtech.spatial4j.shape.Rectangle queryBox,
                                                      double queryTargetProportion)

Returns a similarity based on BBoxOverlapRatioValueSource. This is just a convenience method.

makeQuery

public Query makeQuery(SpatialArgs args)

Description copied from class: SpatialStrategy

Make a Query based principally on SpatialOperation and Shape from the supplied args. It should be constant scoring of 1.

Specified by:

makeQuery in class SpatialStrategy