Class GeohashReferenceSystem.Coder
- Enclosing class:
GeohashReferenceSystem
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
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Constructor Summary
ModifierConstructorDescriptionprotected
Coder()
Creates a new geohash coder/decoder initialized to the default precision. -
Method Summary
Modifier and TypeMethodDescriptiondecode
(CharSequence geohash) Decodes the given geohash into a latitude and a longitude.encode
(double φ, double λ) Encodes the given latitude and longitude into a geohash.encode
(DirectPosition position) Encodes the given position into a geohash.encode
(DirectPosition position, Quantity<?> precision) Encodes the given position into a geohash with the given precision.int
Returns the length of geohashes strings to be encoded by theencode(DirectPosition)
method.getPrecision
(DirectPosition position) Returns an approximate precision of the geohashes formatted by this coder.final GeohashReferenceSystem
Returns the reference system for which GeoHash identifiers will be encoded or decoded.void
setHashLength
(int length) Sets the length of geohashes strings to be encoded by theencode(DirectPosition)
method.void
setPrecision
(Quantity<?> precision, DirectPosition position) Sets the desired precision of the identifiers formatted by this coder.
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Constructor Details
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Coder
protected Coder()Creates a new geohash coder/decoder initialized to the default precision.
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Method Details
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getReferenceSystem
Returns the reference system for which GeoHash identifiers will be encoded or decoded.- Specified by:
getReferenceSystem
in classReferencingByIdentifiers.Coder
- Returns:
- the enclosing reference system.
- Since:
- 1.3
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getHashLength
public int getHashLength()Returns the length of geohashes strings to be encoded by theencode(DirectPosition)
method. The default value forGeohashReferenceSystem.Format.BASE32
is 12.- Returns:
- the length of geohashes strings.
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setHashLength
public void setHashLength(int length) Sets the length of geohashes strings to be encoded by theencode(DirectPosition)
method.- Parameters:
length
- the new length of geohashes strings.
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getPrecision
Returns an approximate precision of the geohashes formatted by this coder. Values are in units of ellipsoid axis length (typically metres). If the location is unspecified, then this method returns a value for the "worst case" scenario, which is at equator. The actual precision is sometimes (but not always) better for coordinates closer to a pole.- Specified by:
getPrecision
in classReferencingByIdentifiers.Coder
- Parameters:
position
- where to evaluate the precision, ornull
for equator.- Returns:
- approximate precision of formatted geohashes.
- Since:
- 1.3
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setPrecision
public void setPrecision(Quantity<?> precision, DirectPosition position) throws IncommensurableException Sets the desired precision of the identifiers formatted by this coder. The given value is converted to a string length.- Specified by:
setPrecision
in classReferencingByIdentifiers.Coder
- Parameters:
precision
- the desired precision in a linear or angular unit.position
- location where the specified precision is desired, ornull
for the equator.- Throws:
IncommensurableException
- if the given precision does not use linear or angular units.- Since:
- 1.3
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encode
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 theGeohashReferenceSystem
constructor. For geohashing of coordinates in different CRS, useencode(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.
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encode
Encodes the given position into a geohash. The default implementation transforms the given position to the coordinate reference system expected by the enclosingGeohashReferenceSystem
, then delegates toencode(double, double)
.- Specified by:
encode
in classReferencingByIdentifiers.Coder
- 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.
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encode
public String encode(DirectPosition position, Quantity<?> precision) throws IncommensurableException, TransformException Encodes the given position into a geohash with the given precision. This is equivalent to invokingsetPrecision(Quantity, DirectPosition)
beforeencode(DirectPosition)
, except that it is potentially more efficient.- Overrides:
encode
in classReferencingByIdentifiers.Coder
- Parameters:
position
- the coordinate to encode.precision
- the desired precision in a linear or angular unit.- Returns:
- geohash encoding of the given position.
- Throws:
IncommensurableException
- if the given precision does not use linear or angular units.TransformException
- if an error occurred while transforming the given coordinate to a geohash reference.- Since:
- 1.3
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decode
Decodes the given geohash into a latitude and a longitude. The axis order depends on the coordinate reference system of the enclosingGeohashReferenceSystem
.Upcoming API change — generalization
in a future SIS version, the type of returned element may be generalized to theorg.opengis.referencing.gazetteer.Location
interface. This change is pending GeoAPI revision.- Specified by:
decode
in classReferencingByIdentifiers.Coder
- 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.
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