com.pb.lisdk.grid.geohash

Class GeoHash

java.lang.Object

com.pb.lisdk.grid.geohash.GeoHash

All Implemented Interfaces:

IGridCell, IHierarchicalGridCell, Serializable

public final class GeoHash
extends Object
implements IHierarchicalGridCell, Serializable

A geohash is a mechanism for bucketing a geographic area (-180, -90, 180, 90) with various levels of precision.

Examples

Determine the hash for the rectangle containing the point (-73.700052, 42.678120) with a precision of 10 characters

          String hash = GeoHash.encode(-73.700052, 42.678120, 10).getHash();

Determine the bounds of the hash "dredfcm606"

          Envelope bounds = GeoHash.decode("dredfcm606").getBounds();

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
IFeatureGeometry	asFeatureGeometry() Get the cell boundary as a geometry
static GeoHash	decode(long bits, int significantBits) Determine the geohash for the specified set of bits.
static GeoHash	decode(String hash) Determine the geohash for the specified well-known string ID.
static List	encode(double minX, double minY, double maxX, double maxY, int precision) Get a list of GeoHashes that cover a rectangle at the specified precision.
static GeoHash	encode(double longitude, double latitude, int precision) Determine the cell that contains the specified point at the specified precision.
boolean	equals(Object o)
long	getBits()
Envelope	getBounds() Get the bounds of the grid cell.
List	getChildren() Get the children of the current cell.
String	getHash() Get the well-known string ID for the hash.
int	hashCode()

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Method Detail

getBits

public long getBits()

getHash

public String getHash()

Get the well-known string ID for the hash.

Specified by:

getHash in interface IGridCell

getBounds

public Envelope getBounds()

Get the bounds of the grid cell.

Specified by:

getBounds in interface IGridCell

asFeatureGeometry

public IFeatureGeometry asFeatureGeometry()

Description copied from interface: IGridCell

Get the cell boundary as a geometry

Specified by:

asFeatureGeometry in interface IGridCell

getChildren

public List getChildren()

Description copied from interface: IHierarchicalGridCell

Get the children of the current cell. The union of the children should coincide with the area of this cell.

Specified by:

getChildren in interface IHierarchicalGridCell

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

encode

public static GeoHash encode(double longitude,
                             double latitude,
                             int precision)

Determine the cell that contains the specified point at the specified precision.

Parameters:

longitude - The longitude value for the specified point.

latitude - The latitude value for the specified point.

precision - The length of the string key to be returned. The longer the string, the higher the precision (i.e. smaller the rectangle).

decode

public static GeoHash decode(String hash)

Determine the geohash for the specified well-known string ID.

Parameters:

hash - The well-known string ID.

Returns:

A representation of the geohash.

decode

public static GeoHash decode(long bits,
                             int significantBits)

Determine the geohash for the specified set of bits.

Parameters:

bits - The bits that represent the geohash.

significantBits - The number of bits that represent the geohash. This must be a multiple of 5.

Returns:

A representation of the geohash.

encode

public static List encode(double minX,
                          double minY,
                          double maxX,
                          double maxY,
                          int precision)

Get a list of GeoHashes that cover a rectangle at the specified precision.

Parameters:

minX - The x value of the lower-left corner to cover.

minY - The y value of the lower-left corner to cover.

maxX - The x value of the upper-right corner to cover.

maxY - The y value of the upper-right corner to cover.

precision - The length of the string key to be returned. The longer the string, the higher the precision (i.e. smaller the rectangle).