org.apache.lucene.util

Class GeoHashUtils

java.lang.Object

org.apache.lucene.util.GeoHashUtils

public class GeoHashUtils
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).

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

Field Summary

Fields

Modifier and Type	Field and Description
static char[]	BASE_32
static String	BASE_32_STRING
static int	PRECISION

Constructor Summary

Constructors

Constructor and Description
GeoHashUtils()

Method Summary

Methods

Modifier and Type	Method and 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	addNeighbors(String geohash, int length, E neighbors) Add all geohashes of the cells next to a given geohash to a list.
static long	fromMorton(long morton, int level)
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	longEncode(long geohash, int level) Encode an existing geohash long to the provided precision
static long	longEncode(String hash) Encode from geohash string to the geohash based long format (lon/lat interleaved, 4 least significant bits = level)
static long	mortonEncode(long geoHashLong) Encode to a morton long value from a given geohash long value
static long	mortonEncode(String hash) Encode to a morton long value from a given geohash string
static String	neighbor(String geohash, int level, int dx, int dy) Calculate the geohash of a neighbor of a geohash
static Collection<? extends CharSequence>	neighbors(String geohash) Calculate all neighbors of a given geohash cell.
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 String	stringEncodeFromMortonLong(long hashedVal) Encode to a full precision geohash string from a given morton encoded long value
static String	stringEncodeFromMortonLong(long hashedVal, int level) Encode to a geohash string at a given level from a morton long

Methods inherited from class java.lang.Object

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

Field Detail

BASE_32

public static final char[] BASE_32

BASE_32_STRING

public static final String BASE_32_STRING

PRECISION

public static final int PRECISION

See Also:

Constant Field Values

Constructor Detail

GeoHashUtils

public GeoHashUtils()

Method Detail

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)

longEncode

public static final long longEncode(String hash)

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

longEncode

public static long longEncode(long geohash,
              int level)

Encode an existing geohash long to the provided precision

fromMorton

public static long fromMorton(long morton,
              int level)

stringEncode

public static final String stringEncode(long geoHashLong)

Encode to a geohash string from the geohash based long format

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

stringEncodeFromMortonLong

public static final String stringEncodeFromMortonLong(long hashedVal)
                                               throws Exception

Encode to a full precision geohash string from a given morton encoded long value

Throws:

Exception

stringEncodeFromMortonLong

public static final String stringEncodeFromMortonLong(long hashedVal,
                                int level)

Encode to a geohash string at a given level from a morton long

mortonEncode

public static final long mortonEncode(String hash)

Encode to a morton long value from a given geohash string

mortonEncode

public static final long mortonEncode(long geoHashLong)

Encode to a morton long value from a given geohash long value

neighbors

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

Calculate all neighbors of a given geohash cell.

Parameters:

geohash - Geohash of the defined cell

Returns:

geohashes of all neighbor cells

neighbor

public static final String neighbor(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

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

addNeighbors

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

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

Parameters:

geohash - Geohash of a specified cell

length - level of the given geohash

neighbors - list to add the neighbors to

Returns:

the given list