Package org.elasticsearch.geometry.utils

Class Geohash

java.lang.Object

org.elasticsearch.geometry.utils.Geohash

public class Geohash
extends Object

Utilities for converting to/from the GeoHash standard The geohash long format is represented as lon/lat (x/y) interleaved with the 4 least significant bits representing the level (1-12) [xyxy...xyxyllll] This differs from a morton encoded value which interleaves lat/lon (y/x). NOTE: this will replace org.elasticsearch.common.geo.GeoHashUtils

Field Summary

Fields

Modifier and Type	Field	Description
static int	PRECISION	maximum precision for geohash strings

Method Summary

Modifier and Type	Method	Description
static <E extends Collection<? super String>> E	addNeighbors(String geohash, E neighbors)	Add all geohashes of the cells next to a given geohash to a list.
static <E extends Collection<? super String>> E	addNeighborsAtLevel(String geohash, int level, E neighbors)	Add all geohashes of the cells next to a given geohash to a list.
static double	decodeLatitude(long hash)	decode latitude value from morton encoded geo point
static double	decodeLatitude(String geohash)	returns the latitude value from the string based geohash
static double	decodeLongitude(long hash)	decode longitude value from morton encoded geo point
static double	decodeLongitude(String geohash)	returns the latitude value from the string based geohash
static int	encodeLatitude(double latitude)	encode latitude to integer
static int	encodeLongitude(double longitude)	encode longitude to integer
static String	getNeighbor(String geohash, int level, int dx, int dy)	Calculate the geohash of a neighbor of a geohash
static Collection<? extends CharSequence>	getNeighbors(String geohash)	Calculate all neighbors of a given geohash cell.
static long	longEncode(double lon, double lat, int level)	Encode lon/lat to the geohash based long format (lon/lat interleaved, 4 least significant bits = level)
static long	mortonEncode(String hash)	Encode to a morton long value from a given geohash string
static String	stringEncode(double lon, double lat)	Encode to a geohash string from full resolution longitude, latitude)
static String	stringEncode(double lon, double lat, int level)	Encode to a level specific geohash string from full resolution longitude, latitude
static String	stringEncode(long geoHashLong)	Encode to a geohash string from the geohash based long format
static Rectangle	toBoundingBox(String geohash)	Computes the bounding box coordinates from a given geohash
static Point	toPoint(String geohash)	Returns a Point instance from a geohash string

Methods inherited from class java.lang.Object

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

Field Detail

PRECISION

public static final int PRECISION

maximum precision for geohash strings

See Also:

Constant Field Values

Method Detail

toPoint

public static Point toPoint(String geohash)
                     throws IllegalArgumentException

Returns a Point instance from a geohash string

Throws:

IllegalArgumentException

toBoundingBox

public static Rectangle toBoundingBox(String geohash)

Computes the bounding box coordinates from a given geohash

Parameters:

geohash - Geohash of the defined cell

Returns:

GeoRect rectangle defining the bounding box

getNeighbors

public static Collection<? extends CharSequence> getNeighbors(String geohash)

Calculate all neighbors of a given geohash cell.

Parameters:

geohash - Geohash of the defined cell

Returns:

geohashes of all neighbor cells

addNeighbors

public static final <E extends Collection<? super String>> E addNeighbors(String geohash,
                                                                          E neighbors)

Add all geohashes of the cells next to a given geohash to a list.

Parameters:

geohash - Geohash of a specified cell

neighbors - list to add the neighbors to

Returns:

the given list

addNeighborsAtLevel

public static final <E extends Collection<? super String>> E addNeighborsAtLevel(String geohash,
                                                                                 int level,
                                                                                 E neighbors)

Add all geohashes of the cells next to a given geohash to a list.

Parameters:

geohash - Geohash of a specified cell

level - level of the given geohash

neighbors - list to add the neighbors to

Returns:

the given list

getNeighbor

public static final String getNeighbor(String geohash,
                                       int level,
                                       int dx,
                                       int dy)

Calculate the geohash of a neighbor of a geohash

Parameters:

geohash - the geohash of a cell

level - level of the geohash

dx - delta of the first grid coordinate (must be -1, 0 or +1)

dy - delta of the second grid coordinate (must be -1, 0 or +1)

Returns:

geohash of the defined cell

longEncode

public static final long longEncode(double lon,
                                    double lat,
                                    int level)

Encode lon/lat to the geohash based long format (lon/lat interleaved, 4 least significant bits = level)

stringEncode

public static final String stringEncode(double lon,
                                        double lat)

Encode to a geohash string from full resolution longitude, latitude)

stringEncode

public static final String stringEncode(double lon,
                                        double lat,
                                        int level)

Encode to a level specific geohash string from full resolution longitude, latitude

stringEncode

public static final String stringEncode(long geoHashLong)

Encode to a geohash string from the geohash based long format

mortonEncode

public static long mortonEncode(String hash)

Encode to a morton long value from a given geohash string

encodeLatitude

public static int encodeLatitude(double latitude)

encode latitude to integer

encodeLongitude

public static int encodeLongitude(double longitude)

encode longitude to integer

decodeLatitude

public static final double decodeLatitude(String geohash)

returns the latitude value from the string based geohash

decodeLongitude

public static final double decodeLongitude(String geohash)

returns the latitude value from the string based geohash

decodeLongitude

public static double decodeLongitude(long hash)

decode longitude value from morton encoded geo point

decodeLatitude

public static double decodeLatitude(long hash)

decode latitude value from morton encoded geo point