node-geohash

by sunng87

sunng87 /node-geohash

geohash library for nodejs

430 Stars 56 Forks Last release: Not found MIT License 98 Commits 9 Releases

Available items

No Items, yet!

The developer of this repository has not created any items for sale yet. Need a bug fixed? Help with integration? A different license? Create a request here:

node-geohash

Geohash library for nodejs.

Build Status NPM version Dependencies Donate

Install

npm install ngeohash

Usage

var geohash = require('ngeohash');
console.log(geohash.encode(37.8324, 112.5584));
// prints ww8p1r4t8
var latlon = geohash.decode('ww8p1r4t8');
console.log(latlon.latitude);
console.log(latlon.longitude);

Basic Methods

geohash.encode (latitude, longitude, precision=9)

Encode a pair of latitude and longitude values into a geohash. The third argument is optional, you can specify a length of this hash string, which also affects the precision of the geohash.

geohash.decode (hashstring)

Decode a hash string into pair of latitude and longitude values. A javascript object is returned with

latitude
and
longitude
keys.

geohash.decode_bbox (hashstring)

Decode hashstring into a bounding box that matches it. Data is returned as a four-element array:

[minlat, minlon, maxlat, maxlon]
.

geohash.bboxes (minlat, minlon, maxlat, maxlon, precision=9)

Get all hashstringes between

[minlat, minlon]
and
[maxlat, maxlon]
. These keys can be used to find a poi stored in the cache with hashstring keys. eg. show all points in the visible range of map

geohash.neighbor (hashstring, direction)

Find the neighbor of a geohash string in certain direction. Direction is a two-element array, i.e.

[1,0]
means north,
[-1,-1]
means southwest.

geohash.neighbors (hashstring)

Find all 8 geohash neighbors

[n, ne, e, se, s, sw, w, nw]
of a geohash string. This method is more efficient than running the geohash.neighbor method multiple times for all directions. array:
[hashstr1, hashstr2, ... ]

Integer Methods

Note that integer precision is capped at 52bits in Javscript. These are just regular javascript floating point numbers, but the functionality should mimic other uint64 geohash functions in geohash libraries for other languages and are compatible with the geohash integers produced by them, however any geohash integer encoded in anything more than 52bits will be resolved to 52bits resolution.

geohash.encode_int (latitude, longitude, bitDepth=52)

Encode a pair of latitude and longitude values into a geohash integer. The third argument is optional, you can specify the

bitDepth
of this number, which affects the precision of the geohash but also must be used consistently when decoding. Bit depth must be even.

geohash.decode_int (hashinteger, bitDepth=52)

Decode a integer geohashed number into pair of latitude and longitude value approximations. A javascript object is returned with

latitude
and
longitude
keys. You should also provide the
bitDepth
at which to decode the number (ie. what bitDepth the number was originally produced with), but will default to 52.

geohash.decodebboxint (hashinteger, bitDepth=52)

Decode an integer geohash into the bounding box that matches it. Data is returned as a four-element array:

[minlat, minlon, maxlat, maxlon]
.

geohash.bboxes_int (minlat, minlon, maxlat, maxlon, bitDepth=52)

Get all geohash integers between

[minlat, minlon]
and
[maxlat, maxlon]
. These keys can be used to find a poi stored in the cache with geohash integer keys. eg. show all points in the visible range of map

geohash.neighbor_int (hashinteger, direction, bitDepth=52)

Find the neighbor of a geohash integer in certain direction. Direction is a two-element array, i.e.

[1,0]
means north,
[-1,-1]
means southwest. The
bitDepth
should be specified, but defaults to 52 bits.

geohash.neighbors_int (hashinteger, bitDepth=52)

Find all 8 neighbors

[n, ne, e, se, s, sw, w, nw]
of a geohash integer. This method is more efficient than running the geohash.neighbor method multiple times for all directions. The
bitDepth
should be specified, but defaults to 52 bits.

Node-Geohash for browser

We recently added a browserify hook in

npm
install
.
ngeohash.js
will be generated during
npm install
, and you can use this file in your javascript application for browser.

About Geohash

Check Wikipedia for more information.

See Also

Geohash.rs: node-geohash ported to Rust: A rust library for geohash.

License

node-geohash is open sourced under MIT License, of course.

Donation

I'm now accepting donation on liberapay, if you find my work helpful and want to keep it going.

We use cookies. If you continue to browse the site, you agree to the use of cookies. For more information on our use of cookies please see our Privacy Policy.