JSDoc: Global

Members

(constant) BASE32 :string

BASE32

Type:

string

Source:

variables.js, line 13

(constant) BASE32_DICT :object

BASE32_DICT

Type:

object

Source:

variables.js, line 18

(constant) BORDER_CODEX :object

BORDER_CODEX

Type:

object

Source:

variables.js, line 56

(constant) ENCODE_AUTO :number

ENCODE_AUTO

Type:

number

Source:

variables.js, line 66

(constant) MAX_LAT :number

MAX_LAT Maximum latitude 90º north of the equator

Type:

number

Source:

variables.js, line 93

(constant) MAX_LNG :number

Maximum longitude 180º east of the prime meridian

Type:

number

Source:

variables.js, line 87

(constant) MIN_LAT :number

Minimum latitude 90º south (-90º) of the equator

Type:

number

Source:

variables.js, line 80

(constant) MIN_LNG :number

Minimum longitude 180º west (-180º) of the prime meridian

Type:

number

Source:

variables.js, line 73

(constant) NEIGHBOR_CODEX :object

NEIGHBOR_CODEX

Type:

object

Source:

variables.js, line 46

(constant) PRECISION_AREA :object

PRECISION_AREA

Type:

object

Source:

variables.js, line 28

(constant) SIGFIG_HASH_LENGTH :Array

Significant Figure Hash Length

This is a quick and dirty lookup to figure out how long our hash should be in order to guarantee a certain amount of trailing significant figures. This was calculated by determining the error: 45/2^(n-1) where n is the number of bits for a latitude or longitude. Key is number of desired sig figs, value is minimum length of the geohash.

Type:

Array

Source:

variables.js, line 105

Methods

clamp(n, min, max) → {number|*}

basic number clamp

Parameters:

Name	Type	Description
`n`	number	number to clamp
`min`	number	minimum value
`max`	number	maximum value

Source:

utils.js, line 37

Returns:

clamped value

Type: number | *

clampRelative(n, min, max) → {number|*}

basic relative value clamp

Parameters:

Name	Type	Description
`n`	number	number to clamp
`min`	number	minimum value
`max`	number	maximum value

Source:

utils.js, line 82

Returns:

clamped value or offset

Type: number | *

decode(geohash, calculateErrorOffsetopt) → {Object|Object}

decode Decode geohash to latitude/longitude (location is approximate centre of geohash cell, to reasonable precision). Will round to close to centre without excessive precision: ⌊2-log10(Δ°)⌋ decimal places.

Parameters:

Name	Type	Attributes	Default	Description
`geohash`	string			Geohash string to be converted to latitude/longitude.
`calculateErrorOffset`	boolean	<optional>	false	calculate the natural amount of geospatial inaccuracy

Source:

decode.js, line 24

Throws:

Invalid geohash.

Returns:

Center of geohashed location.

Type: Object | Object

Example

const latlng = decode( 'dqbvhgk' ); // latlng: { lng: -77.4804, lat: 38.8662 }

determinePrecision(lng, lat, precisionopt, nullable) → {number}

Estimate what precision to use based on the input longitude/latitude

Parameters:

Name	Type	Attributes	Default	Description
`lng`	number			longitude
`lat`	number			latitude
`precision`	number	<optional> <nullable>	ENCODE_AUTO	precision override

Source:

utils.js, line 131

Returns:

precision estimate

Type: number

encode(lng, lat, precisionopt) → {string}

encode Encodes latitude/longitude to geohash, either to specified precision or to automatically evaluated precision.

Parameters:

Name	Type	Attributes	Default	Description
`lng`	number			Longitude in degrees.
`lat`	number			Latitude in degrees.
`precision`	number	<optional>	ENCODE_AUTO	Number of characters in resulting geohash.

Source:

encode.js, line 38

Throws:

Invalid geohash.

Returns:

Geohash of supplied latitude/longitude.

Type: string

Example

const geohash = Geohash.encode(52.205, 0.119, 7); // geohash: 'u120fxw'

geohashesWithinBBox(minLng, minLat, maxLng, maxLat, precisionopt) → {Array}

geohashesWithinBBox

Return all the geohashes between minLng, minLat, maxLng, maxLat at the specified precision

Parameters:

Name	Type	Attributes	Default	Description
`minLng`	number			bbox min longitude
`minLat`	number			bbox min latitude
`maxLng`	number			bbox max longitude
`maxLat`	number			bbox max latitude
`precision`	number	<optional>	ENCODE_AUTO	geohash precision

Source:

geohashesWithinBBox.js, line 25

Returns:

geohash array

Type: Array

geohashesWithinBBoxToGeoJSON(minLng, minLat, maxLng, maxLat, precisionopt) → {Object}

geohashesWithinBBoxToGeoJSON

Return GeoJSON FeatureCollection of all geohashes between minLng, minLat, maxLng, maxLat at the specified precision

Parameters:

Name	Type	Attributes	Default	Description
`minLng`	number			bbox min longitude
`minLat`	number			bbox min latitude
`maxLng`	number			bbox max longitude
`maxLat`	number			bbox max latitude
`precision`	number	<optional>	ENCODE_AUTO	geohash precision

Source:

geohashesWithinBBoxToGeoJSON.js, line 26

Returns:

GeoJSON of geohashes within a bbox

Type: Object

geohashToBBox(hash) → {Array.<number>}

Returns BBox bounds of specified geohash.

Parameters:

Name	Type	Description
`hash`	string	geohash to convert to bbox

Source:

geohashToBBox.js, line 25

Throws:

Invalid geohash.

Returns:

bbox array

Type: Array.<number>

getBBoxStartingPoint(minLng, minLat, maxLng, maxLat, precisionopt) → {Object}

getBBoxStartingPoint

Beginning operations for generating a geohash bbox. Get the geohash for the southwest corner of a bbox and how many hash steps there are to the northeast corner.

Parameters:

Name	Type	Attributes	Default	Description
`minLng`	number			minimum longitude
`minLat`	number			minimum latitude
`maxLng`	number			maximum longitude
`maxLat`	number			maximum latitude
`precision`	number	<optional>	ENCODE_AUTO	geohash precision

Source:

getBBoxStartingPoint.js, line 28

Returns:

southwest hash and how many lng/lat steps to the northeast hash

Type: Object

isNumber(n) → {boolean}

determine if value is a valid number

Parameters:

Name	Type	Description
`n`	number	value

Source:

utils.js, line 24

Returns:

true if value is a number

Type: boolean

latitudeClamp(lat) → {number}

Determines if latitude is in the realm of possibility If it's not, clamp the latitude value to the MIN/MAX

Parameters:

Name	Type	Description
`lat`	number	latitude

Source:

utils.js, line 65

Returns:

latitude

Type: number

latitudeClampRelative(lat) → {number}

Determines if latitude is in the realm of possibility If it's not, return the latitude position relative to the amount offset

Parameters:

Name	Type	Description
`lat`	number	latitude

Source:

utils.js, line 113

Returns:

latitude

Type: number

longitudeClamp(lng) → {number}

Determines if longitude is in the realm of possibility If it's not, clamp the longitude value to the MIN/MAX

Parameters:

Name	Type	Description
`lng`	number	longitude

Source:

utils.js, line 49

Returns:

longitude

Type: number

longitudeClampRelative(lng) → {number}

Determines if longitude is in the realm of possibility If it's not, return the longitude position relative to the amount offset

Parameters:

Name	Type	Description
`lng`	number	longitude

Source:

utils.js, line 97

Returns:

longitude

Type: number

neighbor(geohash, direction) → {string}

Determines neighbor cell in given direction.

Parameters:

Name	Type	Description
`geohash`	string	Cell to which neighbor cell is required.
`direction`	string	Direction from geohash (N/S/E/W).

Source:

neighbor.js, line 23

Throws:

Invalid geohash.

Returns:

Geocode of neighbor cell.

Type: string

neighbors(geohash, asObject) → {Object|array}

Parameters:

Name	Type	Default	Description
`geohash`	string		Geohash neighbors are required of.
`asObject`	boolean	false	to return as an object or array

Source:

neighbors.js, line 23

Throws:

Invalid geohash.

Returns:

surrounding geohashes

Type: Object | array

sizeOf(geohash) → {Object}

sizeOf Calculate the size of a given geohash

Precision	Width	Height
1	`≤ 5,000km`	`× 5,000km`
2	`≤ 1,250km`	`× 625km`
3	`≤ 156km`	`× 156km`
4	`≤ 39.1km`	`× 19.5km`
5	`≤ 4.89km`	`× 4.89km`
6	`≤ 1.22km`	`× 0.61km`
7	`≤ 153m`	`× 153m`
8	`≤ 38.2m`	`× 19.1m`
9	`≤ 4.77m`	`× 4.77m`
10	`≤ 1.19m`	`× 0.596m`
11	`≤ 149mm`	`× 149mm`
12	`≤ 37.2mm`	`× 18.6mm`

Parameters:

Name	Type	Description
`geohash`	string	Geohash to determine precision size

Source:

sizeOf.js, line 36

Returns:

area, width, and high in meters

Type: Object

Example

sizeOf( 'dqcjpxetz' );
// { geohash: 'dqcjpxetz', precision: 9, width: 4.77, height: 4.77, area: 22.7527 }

toGeoJSON(hash, opts) → {*}

convert geohash to GeoJSON

Parameters:

Name Type Description

hash

string

geohash to convert

opts

object

geojson options

Properties

Name	Type	Attributes	Default	Description
`includeGeohashAsProperty`	boolean	<optional>	false	include geohash string as a property in the GeoJSON
`includeFeatureBBox`	boolean	<optional>	false	include bbox as a property in the GeoJSON

Source:

toGeoJSON.js, line 23

Returns:

geohash to geojson

Type: *

validGeohash(geohash) → {boolean}

validGeohash Determine if string is a valid geohash

Parameters:

Name	Type	Description
`geohash`	string	geohash to test

Source:

validGeohash.js, line 14

Returns:

true/false if the geohash is valid

Type: boolean