Class GeoHash

Provides function to encode/decode geo coordinates into and from GeoHash Geohash is a public domain geocode system invented in 2008 by Gustavo Niemeyer which encodes a geographic location into a short string of letters and digits. It is a hierarchical spatial data structure which subdivides space into buckets of grid shape, which is one of the many applications of what is known as a Z-order curve, and generally space-filling curves.
Inheritance
System.Object
GeoHash
Namespace: Mars.Common
Assembly: Mars.Common.dll
Syntax
public static class GeoHash : object
Remarks
Geohashes offer properties like arbitrary precision and the possibility of gradually removing characters from the end of the code to reduce its size (and gradually lose precision). Geohashing guarantees that the longer a shared prefix between two geohashes is, the spatially closer they are together. The reverse of this is not guaranteed, as two points can be very close but have a short or no shared prefix.

Methods

Bboxes(Double, Double, Double, Double, Int32)

Declaration
public static string[] Bboxes(double minLat, double minLon, double maxLat, double maxLon, int numberOfChars = 9)
Parameters
Type Name Description
System.Double minLat
System.Double minLon
System.Double maxLat
System.Double maxLon
System.Int32 numberOfChars
Returns
Type Description
System.String[]

BboxesInt(Double, Double, Double, Double, Int32)

Declaration
public static long[] BboxesInt(in double minLat, in double minLon, in double maxLat, in double maxLon, in int bitDepth = 52)
Parameters
Type Name Description
System.Double minLat
System.Double minLon
System.Double maxLat
System.Double maxLon
System.Int32 bitDepth
Returns
Type Description
System.Int64[]

Decode(String)

Declaration
public static GeohashDecodeResult Decode(in string hashString)
Parameters
Type Name Description
System.String hashString
Returns
Type Description
GeohashDecodeResult

DecodeBbox(String)

Declaration
public static BoundingBox DecodeBbox(in string hashString)
Parameters
Type Name Description
System.String hashString
Returns
Type Description
BoundingBox

DecodeBboxInt(Int64, Int32)

Declaration
public static BoundingBox DecodeBboxInt(in long hashInt, in int bitDepth = 52)
Parameters
Type Name Description
System.Int64 hashInt
System.Int32 bitDepth
Returns
Type Description
BoundingBox

DecodeInt(Int64, Int32)

Declaration
public static GeohashDecodeResult DecodeInt(in long hashInt, in int bitDepth = 52)
Parameters
Type Name Description
System.Int64 hashInt
System.Int32 bitDepth
Returns
Type Description
GeohashDecodeResult

Encode(Double, Double, Int32)

Converts the input geo-coordinate described by longitude, latitude into a GeoHash string.
Declaration
public static string Encode(double longitude, double latitude, in int precision = 9)
Parameters
Type Name Description
System.Double longitude The x/longitude component of the coordinate.
System.Double latitude The y/latitude component of the coordinate.
System.Int32 precision The amount of bits to take into calculation to reduce or increase the error prone (GeoHashPrecision.
Returns
Type Description
System.String Returns the GeoHash as a string representing the specified geo-coordinate

EncodeInt(Double, Double, Int32)

Converts the input geo-coordinate described by longitude, latitude into a geohash integer.
Declaration
public static long EncodeInt(double latitude, double longitude, int precision = 52)
Parameters
Type Name Description
System.Double latitude The y/latitude component of the coordinate.
System.Double longitude The x/longitude component of the coordinate.
System.Int32 precision The amount of bits to take into calculation to reduce or increase the error prone (GeoHashPrecision.
Returns
Type Description
System.Int64 Returns the GeoHash as an integer representing the specified geo-coordinate.

EncodeNeighbor(Int32, Int32, Int32, GeohashDecodeResult)

Declaration
public static string EncodeNeighbor(int hashstringLength, int neighborLatDir, int neighborLonDir, GeohashDecodeResult coords)
Parameters
Type Name Description
System.Int32 hashstringLength
System.Int32 neighborLatDir
System.Int32 neighborLonDir
GeohashDecodeResult coords
Returns
Type Description
System.String

EncodeNeighborInt(Int32, Int32, GeohashDecodeResult, Int32)

Declaration
public static long EncodeNeighborInt(in int neighborLatDir, in int neighborLonDir, GeohashDecodeResult coords, int bitDepth)
Parameters
Type Name Description
System.Int32 neighborLatDir
System.Int32 neighborLonDir
GeohashDecodeResult coords
System.Int32 bitDepth
Returns
Type Description
System.Int64

GetNextGreaterPrecision(Double)

Gets the nearest next greater precision for a given cell size
Declaration
public static GeoHashPrecision GetNextGreaterPrecision(double cellSizeInMeter)
Parameters
Type Name Description
System.Double cellSizeInMeter The cell size in meter
Returns
Type Description
GeoHashPrecision

Neighbor(String, Int32[])

Declaration
public static string Neighbor(in string hashString, in int[] direction)
Parameters
Type Name Description
System.String hashString
System.Int32[] direction
Returns
Type Description
System.String

NeighborInt(Int64, Int32[], Int32)

Find neighbor of a geo-hash integer in certain direction. Direction is a two-element array, i.e. [1,0] means north, [-1,-1] means southwest. direction [lat, lon], i.e. [1,0] - north [1,1] - northeast ...
Declaration
public static long NeighborInt(in long hashInt, in int[] direction, in int bitDepth = 52)
Parameters
Type Name Description
System.Int64 hashInt The numeric hash of the neighbour in the desired direction.
System.Int32[] direction The direction to hash
System.Int32 bitDepth The precision
Returns
Type Description
System.Int64

Neighbors(String)

Declaration
public static string[] Neighbors(string hashString)
Parameters
Type Name Description
System.String hashString
Returns
Type Description
System.String[]

NeighborsInt(Int64, Int32)

Declaration
public static long[] NeighborsInt(long hashInt, int bitDepth = 52)
Parameters
Type Name Description
System.Int64 hashInt
System.Int32 bitDepth
Returns
Type Description
System.Int64[]