geoh

Idiomatic C Geohash library and tools

Installation

$ git clone http://github.com/konimarti/geoh
$ make 
$ sudo make install

Getting started

To calculate a geohash from coordinates, you first initiate a struct geoh_hash with the desired precision using geoh_init_hash() function.

struct geoh_hash hash;
geoh_init_hash(&hash, 6);

Once initialized, call the geoh_encode() function with the latitude and longitude variables to be encoded:

double lat, lng;
lat = 41.1234;
lng = 9.5678;
geoh_encode(&hash, lat, lng);
printf("Geohash: %s\n", hash.hash);

Geohash tools usage

• encode [precision] reads in latitude and longitude and calculates the geohash for the given precision:

   $ echo "41.1234 9.5678" | bin/encode 6 
   $ spqccw
   $ echo "41.1234 9.5678" | bin/encode 12 
   $ spqccwr11vku
  

• decode reads a geohash and prints the corresponding latitude and longitude:

   echo "spqccwr11vku" | bin/decode 
   41.123400 9.567800
  

Unit Testing

The unit tests use the cmocka unit testing framework. To run the test, cmocka needs to be installed on your machine to build and run the unit tests.

$ make test

Starting Geohash unit-tests.
[GEOH Tests]
[==========] Running 4 test(s).
[ RUN      ] TEST__init_hash
[       OK ] TEST__init_hash
[ RUN      ] TEST__set_hash
[       OK ] TEST__set_hash
[ RUN      ] TEST__encode
[       OK ] TEST__encode
[ RUN      ] TEST__decode
[       OK ] TEST__decode
[==========] 4 test(s) run.
[  PASSED  ] 4 test(s).