https://github.com/simplegeo/libgeohash

A pure C implementation of the Geohash algorithm.
https://github.com/simplegeo/libgeohash

Last synced: about 19 hours ago
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A pure C implementation of the Geohash algorithm.

• Host: GitHub
• URL: https://github.com/simplegeo/libgeohash
• Owner: simplegeo
• License: bsd-3-clause
• Created: 2009-10-06T18:06:33.000Z (about 15 years ago)
• Default Branch: master
• Last Pushed: 2019-05-05T12:33:47.000Z (over 5 years ago)
• Last Synced: 2024-07-31T22:55:18.425Z (3 months ago)
• Language: C
• Homepage: http://geohash.org
• Size: 218 KB
• Stars: 104
• Watchers: 13
• Forks: 33
• Open Issues: 5
• Metadata Files:
  • Readme: README.markdown
  • License: LICENSE

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README

        
libgeohash

==========

Derek Smith 

-----------

[email protected]

-------------------

A static library used for encoding/decoding geohashes.

To use libgeohash just run make. Link libgeohash.a and include geohash.h into your project.

### Encode

char* geohash_encode(double lat, double lng, int precision);

Takes in latitude and longitude with a desired precision and returns the correct hash value. If

precision < 0 or precision > 20, a default value of 6 will be used.

### Decode

GeoCoord geohash_decode(char* hash);

Produces an allocated GeoCoord structure which contains the latitude and longitude that was decoded from

the geohash. A GeoCoord also provides the bounding box for the geohash (north, east, south, west).

### Neighbors

char** geohash_neighbors(char* hash);

Uses the bounding box declared at hash and calculates the 8 neighboring boxes. An example is show below.

+ ezefx ezs48 ezs49

+ ezefr ezs42 ezs43

+ ezefp ezs40 ezs41

The value returned is an array of char* with length of 8. The neighboring positions of values are shown 

below with each box representing the index of the array.

+ 7 0 1

+ 6 * 2

+ 5 4 3