Package org.apache.lucene.geo

# Class GeoEncodingUtils

java.lang.Object
org.apache.lucene.geo.GeoEncodingUtils

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.

## Nested Class Summary

Nested Classes
Modifier and Type
Class
Description
`static class`
`GeoEncodingUtils.Component2DPredicate`
A predicate that checks whether a given point is within a component2D geometry.
`static class`
`GeoEncodingUtils.DistancePredicate`
A predicate that checks whether a given point is within a distance of another point.

## Field Summary

Fields
Modifier and Type
Field
Description
`static final short`
`BITS`
number of bits used for quantizing latitude and longitude values
`static final int`
`MAX_LON_ENCODED`
`static final int`
`MIN_LON_ENCODED`

## Method Summary

Modifier and Type
Method
Description
`static GeoEncodingUtils.Component2DPredicate`
`createComponentPredicate(Component2D tree)`
Create a predicate that checks whether points are within a geometry.
`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.
`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 Details

### BITS

public static final short BITS
number of bits used for quantizing latitude and longitude values

See Also:
  - Constant Field Values

### MIN_LON_ENCODED

public static final int MIN_LON_ENCODED

### MAX_LON_ENCODED

public static final int MAX_LON_ENCODED

## Method Details

### 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

### 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

### 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

### 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

### 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.

### 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.

### createComponentPredicate

public static GeoEncodingUtils.Component2DPredicate createComponentPredicate(Component2D tree)
Create a predicate that checks whether points are within a geometry. It works the same way as `createDistancePredicate(double, double, double)`.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.