TupleEntry argument = functionCall.getArguments();
Double lat = argument.getDouble( 0 );
Double lng = argument.getDouble( 1 );
GeoHashUtils ghu = new GeoHashUtils();
String geohash = ghu.encode( lat, lng );
Tuple result = new Tuple();
result.add( geohash.substring( 0, hash_length ) );
functionCall.getOutputCollector().add( result );
}