Package org.apache.lucene.geo
Class GeoEncodingUtils
- java.lang.Object
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- org.apache.lucene.geo.GeoEncodingUtils
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public final class GeoEncodingUtils extends Object
reusable geopoint encoding methods- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static classGeoEncodingUtils.Component2DPredicateA predicate that checks whether a given point is within a component2D geometry.static classGeoEncodingUtils.DistancePredicateA predicate that checks whether a given point is within a distance of another point.
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Field Summary
Fields Modifier and Type Field Description static shortBITSnumber of bits used for quantizing latitude and longitude valuesstatic intMAX_LON_ENCODEDstatic intMIN_LON_ENCODED
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static GeoEncodingUtils.Component2DPredicatecreateComponentPredicate(Component2D tree)Create a predicate that checks whether points are within a geometry.static GeoEncodingUtils.DistancePredicatecreateDistancePredicate(double lat, double lon, double radiusMeters)Create a predicate that checks whether points are within a distance of a given point.static doubledecodeLatitude(byte[] src, int offset)Turns quantized value from byte array back into a double.static doubledecodeLatitude(int encoded)Turns quantized value fromencodeLatitude(double)back into a double.static doubledecodeLongitude(byte[] src, int offset)Turns quantized value from byte array back into a double.static doubledecodeLongitude(int encoded)Turns quantized value fromencodeLongitude(double)back into a double.static intencodeLatitude(double latitude)Quantizes double (64 bit) latitude into 32 bits (rounding down: in the direction of -90)static intencodeLatitudeCeil(double latitude)Quantizes double (64 bit) latitude into 32 bits (rounding up: in the direction of +90)static intencodeLongitude(double longitude)Quantizes double (64 bit) longitude into 32 bits (rounding down: in the direction of -180)static intencodeLongitudeCeil(double longitude)Quantizes double (64 bit) longitude into 32 bits (rounding up: in the direction of +180)
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Field Detail
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BITS
public static final short BITS
number of bits used for quantizing latitude and longitude values- See Also:
- Constant Field Values
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MIN_LON_ENCODED
public static final int MIN_LON_ENCODED
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MAX_LON_ENCODED
public static final int MAX_LON_ENCODED
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Method Detail
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encodeLatitude
public static int encodeLatitude(double latitude)
Quantizes double (64 bit) latitude into 32 bits (rounding down: in the direction of -90)- Parameters:
latitude- latitude value: must be within standard +/-90 coordinate bounds.- Returns:
- encoded value as a 32-bit
int - Throws:
IllegalArgumentException- if latitude is out of bounds
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encodeLatitudeCeil
public static int encodeLatitudeCeil(double latitude)
Quantizes double (64 bit) latitude into 32 bits (rounding up: in the direction of +90)- Parameters:
latitude- latitude value: must be within standard +/-90 coordinate bounds.- Returns:
- encoded value as a 32-bit
int - Throws:
IllegalArgumentException- if latitude is out of bounds
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encodeLongitude
public static int encodeLongitude(double longitude)
Quantizes double (64 bit) longitude into 32 bits (rounding down: in the direction of -180)- Parameters:
longitude- longitude value: must be within standard +/-180 coordinate bounds.- Returns:
- encoded value as a 32-bit
int - Throws:
IllegalArgumentException- if longitude is out of bounds
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encodeLongitudeCeil
public static int encodeLongitudeCeil(double longitude)
Quantizes double (64 bit) longitude into 32 bits (rounding up: in the direction of +180)- Parameters:
longitude- longitude value: must be within standard +/-180 coordinate bounds.- Returns:
- encoded value as a 32-bit
int - Throws:
IllegalArgumentException- if longitude is out of bounds
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decodeLatitude
public static double decodeLatitude(int encoded)
Turns quantized value fromencodeLatitude(double)back into a double.- Parameters:
encoded- encoded value: 32-bit quantized value.- Returns:
- decoded latitude value.
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decodeLatitude
public static double decodeLatitude(byte[] src, int offset)Turns quantized value from byte array back into a double.- Parameters:
src- byte array containing 4 bytes to decode atoffsetoffset- offset intosrcto decode from.- Returns:
- decoded latitude value.
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decodeLongitude
public static double decodeLongitude(int encoded)
Turns quantized value fromencodeLongitude(double)back into a double.- Parameters:
encoded- encoded value: 32-bit quantized value.- Returns:
- decoded longitude value.
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decodeLongitude
public static double decodeLongitude(byte[] src, int offset)Turns quantized value from byte array back into a double.- Parameters:
src- byte array containing 4 bytes to decode atoffsetoffset- offset intosrcto decode from.- Returns:
- decoded longitude value.
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createDistancePredicate
public static GeoEncodingUtils.DistancePredicate createDistancePredicate(double lat, double lon, double radiusMeters)
Create a predicate that checks whether points are within a distance of a given point. It works by computing the bounding box around the circle that is defined by the given points/distance and splitting it into between 1024 and 4096 smaller boxes (4096*0.75^2=2304 on average). Then for each sub box, it computes the relation between this box and the distance query. Finally at search time, it first computes the sub box that the point belongs to, most of the time, no distance computation will need to be performed since all points from the sub box will either be in or out of the circle.- NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
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createComponentPredicate
public static GeoEncodingUtils.Component2DPredicate createComponentPredicate(Component2D tree)
Create a predicate that checks whether points are within a geometry. It works the same way ascreateDistancePredicate(double, double, double).- NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
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