Class PointVectorStrategy

Simple SpatialStrategy which represents Points in two numeric Lucene.Net.Documents.DoubleFields. The Strategy's best feature is decent distance sort.

Characteristics:

• Only indexes points; just one per field value.
• Can query by a rectangle or circle.
• Intersects and IsWithin is supported.
• Uses the FieldCache for MakeDistanceValueSource(IPoint) and for searching with a Circle.

Implementation:

This is a simple Strategy. Search works with Lucene.Net.Search.NumericRangeQuerys on an x & y pair of fields. A Circle query does the same bbox query but adds a ValueSource filter on MakeDistanceValueSource(IPoint).

One performance shortcoming with this strategy is that a scenario involving both a search using a Circle and sort will result in calculations for the spatial distance being done twice -- once for the filter and second for the sort.

Note

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

Inheritance

object

SpatialStrategy

PointVectorStrategy

Inherited Members

SpatialStrategy.m_ctx

SpatialStrategy.SpatialContext

SpatialStrategy.FieldName

SpatialStrategy.MakeDistanceValueSource(IPoint)

SpatialStrategy.MakeRecipDistanceValueSource(IShape)

SpatialStrategy.ToString()

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: Lucene.Net.Spatial.Vector

Assembly: Lucene.Net.Spatial.dll

Syntax

public class PointVectorStrategy : SpatialStrategy

Constructors

PointVectorStrategy(SpatialContext, string)

Simple SpatialStrategy which represents Points in two numeric Lucene.Net.Documents.DoubleFields. The Strategy's best feature is decent distance sort.

Characteristics:

• Only indexes points; just one per field value.
• Can query by a rectangle or circle.
• Intersects and IsWithin is supported.
• Uses the FieldCache for MakeDistanceValueSource(IPoint) and for searching with a Circle.

Implementation:

This is a simple Strategy. Search works with Lucene.Net.Search.NumericRangeQuerys on an x & y pair of fields. A Circle query does the same bbox query but adds a ValueSource filter on MakeDistanceValueSource(IPoint).

One performance shortcoming with this strategy is that a scenario involving both a search using a Circle and sort will result in calculations for the spatial distance being done twice -- once for the filter and second for the sort.

Note

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

Declaration

public PointVectorStrategy(SpatialContext ctx, string fieldNamePrefix)

Parameters

Type	Name	Description
SpatialContext	ctx
string	fieldNamePrefix

Fields

SUFFIX_X

Simple SpatialStrategy which represents Points in two numeric Lucene.Net.Documents.DoubleFields. The Strategy's best feature is decent distance sort.

Characteristics:

• Only indexes points; just one per field value.
• Can query by a rectangle or circle.
• Intersects and IsWithin is supported.
• Uses the FieldCache for MakeDistanceValueSource(IPoint) and for searching with a Circle.

Implementation:

This is a simple Strategy. Search works with Lucene.Net.Search.NumericRangeQuerys on an x & y pair of fields. A Circle query does the same bbox query but adds a ValueSource filter on MakeDistanceValueSource(IPoint).

One performance shortcoming with this strategy is that a scenario involving both a search using a Circle and sort will result in calculations for the spatial distance being done twice -- once for the filter and second for the sort.

Note

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

Declaration

public const string SUFFIX_X = "__x"

Field Value

Type	Description
string

SUFFIX_Y

Simple SpatialStrategy which represents Points in two numeric Lucene.Net.Documents.DoubleFields. The Strategy's best feature is decent distance sort.

Characteristics:

• Only indexes points; just one per field value.
• Can query by a rectangle or circle.
• Intersects and IsWithin is supported.
• Uses the FieldCache for MakeDistanceValueSource(IPoint) and for searching with a Circle.

Implementation:

This is a simple Strategy. Search works with Lucene.Net.Search.NumericRangeQuerys on an x & y pair of fields. A Circle query does the same bbox query but adds a ValueSource filter on MakeDistanceValueSource(IPoint).

One performance shortcoming with this strategy is that a scenario involving both a search using a Circle and sort will result in calculations for the spatial distance being done twice -- once for the filter and second for the sort.

Note

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

Declaration

public const string SUFFIX_Y = "__y"

Field Value

Type	Description
string

Properties

PrecisionStep

Simple SpatialStrategy which represents Points in two numeric Lucene.Net.Documents.DoubleFields. The Strategy's best feature is decent distance sort.

Characteristics:

• Only indexes points; just one per field value.
• Can query by a rectangle or circle.
• Intersects and IsWithin is supported.
• Uses the FieldCache for MakeDistanceValueSource(IPoint) and for searching with a Circle.

Implementation:

This is a simple Strategy. Search works with Lucene.Net.Search.NumericRangeQuerys on an x & y pair of fields. A Circle query does the same bbox query but adds a ValueSource filter on MakeDistanceValueSource(IPoint).

One performance shortcoming with this strategy is that a scenario involving both a search using a Circle and sort will result in calculations for the spatial distance being done twice -- once for the filter and second for the sort.

Note

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

Declaration

public virtual int PrecisionStep { get; set; }

Property Value

Type	Description
int

Methods

CreateIndexableFields(IPoint)

See CreateIndexableFields(IShape)

Declaration

public virtual Field[] CreateIndexableFields(IPoint point)

Parameters

Type	Name	Description
IPoint	point

Returns

Type	Description
Field[]

CreateIndexableFields(IShape)

Returns the IndexableField(s) from the shape that are to be added to the Lucene.Net.Documents.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.

Declaration

public override Field[] CreateIndexableFields(IShape shape)

Parameters

Type	Name	Description
IShape	shape

Returns

Type	Description
Field[]	Not null nor will it have null elements.

Overrides

SpatialStrategy.CreateIndexableFields(IShape)

Exceptions

Type	Condition
NotSupportedException	if given a shape incompatible with the strategy

MakeDistanceValueSource(IPoint, double)

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.

Declaration

public override ValueSource MakeDistanceValueSource(IPoint queryPoint, double multiplier)

Parameters

Type	Name	Description
IPoint	queryPoint
double	multiplier

Returns

Type	Description
ValueSource

Overrides

SpatialStrategy.MakeDistanceValueSource(IPoint, double)

MakeFilter(SpatialArgs)

Make a Filter based principally on SpatialOperation and Spatial4n.Shapes.IShape from the supplied args.

If a subclasses implements MakeQuery(SpatialArgs) then this method could be simply:

return new QueryWrapperFilter(MakeQuery(args).Query);

Declaration

public override Filter MakeFilter(SpatialArgs args)

Parameters

Type	Name	Description
SpatialArgs	args

Returns

Type	Description
Filter

Overrides

SpatialStrategy.MakeFilter(SpatialArgs)

Exceptions

Type	Condition
NotSupportedException	If the strategy does not support the shape in args.
UnsupportedSpatialOperationException	If the strategy does not support the SpatialOperation in args.

MakeQuery(SpatialArgs)

Make a Query based principally on SpatialOperation and Spatial4n.Shapes.IShape from the supplied args. The default implementation is

return new ConstantScoreQuery(MakeFilter(args));

Declaration

public override ConstantScoreQuery MakeQuery(SpatialArgs args)

Parameters

Type	Name	Description
SpatialArgs	args

Returns

Type	Description
ConstantScoreQuery

Overrides

SpatialStrategy.MakeQuery(SpatialArgs)

Exceptions

Type	Condition
NotSupportedException	If the strategy does not support the shape in args.
UnsupportedSpatialOperationException	If the strategy does not support the SpatialOperation in args.

MakeQueryDistanceScore(SpatialArgs)

Simple SpatialStrategy which represents Points in two numeric Lucene.Net.Documents.DoubleFields. The Strategy's best feature is decent distance sort.

Characteristics:

• Only indexes points; just one per field value.
• Can query by a rectangle or circle.
• Intersects and IsWithin is supported.
• Uses the FieldCache for MakeDistanceValueSource(IPoint) and for searching with a Circle.

Implementation:

This is a simple Strategy. Search works with Lucene.Net.Search.NumericRangeQuerys on an x & y pair of fields. A Circle query does the same bbox query but adds a ValueSource filter on MakeDistanceValueSource(IPoint).

One performance shortcoming with this strategy is that a scenario involving both a search using a Circle and sort will result in calculations for the spatial distance being done twice -- once for the filter and second for the sort.

Note

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

Declaration

public virtual Query MakeQueryDistanceScore(SpatialArgs args)

Parameters

Type	Name	Description
SpatialArgs	args

Returns

Type	Description
Query