org.apache.sis.referencing.gazetteer

Class GeohashReferenceSystem.Coder

Object

GeohashReferenceSystem.Coder

Enclosing class:

GeohashReferenceSystem

public class GeohashReferenceSystem.Coder
extends Object

Conversions between direct positions and geohashes. Each Coder instance can read codes at arbitrary precision, but formats at the specified precision. The same Coder instance can be reused for reading or writing many geohashes.

Immutability and thread safety

This class is not thread-safe. A new instance must be created for each thread, or synchronization must be applied by the caller.

Since:

0.8

Defined in the sis-referencing-by-identifiers module

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Coder() Creates a new geohash coder/decoder initialized to the default precision.

Method Summary

Modifier and Type	Method and Description
AbstractLocation	decode(CharSequence geohash) Decodes the given geohash into a latitude and a longitude.
String	encode(DirectPosition position) Encodes the given position into a geohash.
String	encode(double φ, double λ) Encodes the given latitude and longitude into a geohash.
int	getHashLength() Returns the length of geohashes strings to be encoded by the encode(Direct­Position) method.
void	setHashLength(int length) Sets the length of geohashes strings to be encoded by the encode(Direct­Position) method.

Methods inherited from class Object

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

Constructor Detail

Coder

protected Coder()

Creates a new geohash coder/decoder initialized to the default precision.

Method Detail

getHashLength

public int getHashLength()

Returns the length of geohashes strings to be encoded by the encode(Direct­Position) method. The default value for Geohash­Reference­System.Format.BASE32 is 12.

Returns:

the length of geohashes strings.

setHashLength

public void setHashLength(int length)

Sets the length of geohashes strings to be encoded by the encode(Direct­Position) method.

Parameters:

length - the new length of geohashes strings.

encode

public String encode(double φ,
                     double λ)
              throws TransformException

Encodes the given latitude and longitude into a geohash. This method does not take in account the axis order and units of the coordinate reference system (CRS) given to the Geohash­Reference­System constructor. For geohashing of coordinates in different CRS, use encode(Direct­Position) instead.

Parameters:

φ - latitude to encode, as decimal degrees in the [-90 … 90]° range.

λ - longitude to encode, as decimal degrees in the [-180 … 180]° range.

Returns:

geohash encoding of the given longitude and latitude.

Throws:

Transform­Exception - if an error occurred while formatting the given coordinate.

encode

public String encode(DirectPosition position)
              throws TransformException

Encodes the given position into a geohash. The default implementation transforms the given position to the coordinate reference system expected by the enclosing Geohash­Reference­System, then delegates to encode(double, double).

Parameters:

position - the coordinate to encode.

Returns:

geohash encoding of the given position.

Throws:

Transform­Exception - if an error occurred while transforming the given coordinate to a geohash reference.

decode

public AbstractLocation decode(CharSequence geohash)
                        throws TransformException

Decodes the given geohash into a latitude and a longitude. The axis order depends on the coordinate reference system of the enclosing Geohash­Reference­System.

Upcoming API change — generalization
in a future SIS version, the type of returned element may be generalized to the org.opengis.referencing.gazetteer.Location interface. This change is pending GeoAPI revision.

Parameters:

geohash - geohash string to decode.

Returns:

a new geographic coordinate for the given geohash.

Throws:

Transform­Exception - if an error occurred while parsing the given string.