org.apache.lucene.geo

Class GeoEncodingUtils

java.lang.Object

org.apache.lucene.geo.GeoEncodingUtils

public final class GeoEncodingUtils
extends java.lang.Object

reusable geopoint encoding methods

Field Summary

Fields

Modifier and Type	Field and Description
static short	BITS number of bits used for quantizing latitude and longitude values
private static double	LAT_DECODE
private static double	LAT_SCALE
private static double	LON_DECODE
private static double	LON_SCALE

Constructor Summary

Constructors

Modifier	Constructor and Description
private	GeoEncodingUtils()

Method Summary

Modifier and Type	Method and Description
static double	decodeLatitude(byte[] src, int offset) Turns quantized value from byte array back into a double.
static double	decodeLatitude(int encoded) Turns quantized value from encodeLatitude(double) back into a double.
static double	decodeLongitude(byte[] src, int offset) Turns quantized value from byte array back into a double.
static double	decodeLongitude(int encoded) Turns quantized value from encodeLongitude(double) back into a double.
static int	encodeLatitude(double latitude) Quantizes double (64 bit) latitude into 32 bits (rounding down: in the direction of -90)
static int	encodeLatitudeCeil(double latitude) Quantizes double (64 bit) latitude into 32 bits (rounding up: in the direction of +90)
static int	encodeLongitude(double longitude) Quantizes double (64 bit) longitude into 32 bits (rounding down: in the direction of -180)
static int	encodeLongitudeCeil(double longitude) Quantizes double (64 bit) longitude into 32 bits (rounding up: in the direction of +180)

Methods inherited from class java.lang.Object

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

Field Detail

BITS

public static final short BITS

number of bits used for quantizing latitude and longitude values

See Also:

Constant Field Values

LAT_SCALE

private static final double LAT_SCALE

See Also:

Constant Field Values

LAT_DECODE

private static final double LAT_DECODE

See Also:

Constant Field Values

LON_SCALE

private static final double LON_SCALE

See Also:

Constant Field Values

LON_DECODE

private static final double LON_DECODE

See Also:

Constant Field Values

Constructor Detail

GeoEncodingUtils

private GeoEncodingUtils()

Method Detail

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:

java.lang.IllegalArgumentException - if latitude is out of bounds

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:

java.lang.IllegalArgumentException - if latitude is out of bounds

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:

java.lang.IllegalArgumentException - if longitude is out of bounds

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:

java.lang.IllegalArgumentException - if longitude is out of bounds

decodeLatitude

public static double decodeLatitude(int encoded)

Turns quantized value from encodeLatitude(double) back into a double.

Parameters:

encoded - encoded value: 32-bit quantized value.

Returns:

decoded latitude value.

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 at offset

offset - offset into src to decode from.

Returns:

decoded latitude value.

decodeLongitude

public static double decodeLongitude(int encoded)

Turns quantized value from encodeLongitude(double) back into a double.

Parameters:

encoded - encoded value: 32-bit quantized value.

Returns:

decoded longitude value.

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 at offset

offset - offset into src to decode from.

Returns:

decoded longitude value.