.. index:: single: geohash
.. _geohash/0:

.. rst-class:: right

**object**

``geohash``
===========

Geohash encoder, decoder, adjacency, covering, hierarchy, integer conversion, bit-precision, and geometry covering predicates for ``geographic(Latitude,Longitude)`` coordinates.

| **Availability:** 
|    ``logtalk_load(geohash(loader))``

| **Author:** Paulo Moura
| **Version:** 1:2:0
| **Date:** 2026-05-11

| **Compilation flags:**
|    ``static, context_switching_calls``


| **Implements:**
|    ``public`` :ref:`geohash_protocol <geohash_protocol/0>`
| **Imports:**
|    ``public`` :ref:`options <options/0>`
| **Uses:**
|    :ref:`geospatial <geospatial/0>`
|    :ref:`list <list/0>`
|    :ref:`type <type/0>`

| **Remarks:**

   - Alphabet: Uses the standard geohash base-32 alphabet ``0123456789bcdefghjkmnpqrstuvwxyz``.
   - Encoding canonicalization: Encoding canonicalizes longitudes to the ``[-180.0,180.0[`` range, treating ``180.0`` as ``-180.0`` so equivalent dateline coordinates map to the same geohash.
   - Bounding boxes: Decoded cells are represented using ``bbox(geographic(MinLatitude,MinLongitude),geographic(MaxLatitude,MaxLongitude))``.
   - Coverage: Bounding-box coverage accepts antimeridian-crossing boxes where the minimum longitude is greater than the maximum longitude.
   - Adaptive covering: Adaptive covers use ``max_precision/1`` together with ``compact/1`` and ``min_precision/1`` options.
   - Integer representation: Integer geohashes are 5-bit packed base-32 values with an explicit precision argument preserving leading zero groups.
   - Geometry covering: Polygon and polyline covering predicates rely on generic ``geospatial`` geometry predicates and do not support antimeridian-crossing input geometries.

| **Inherited public predicates:**
|     :ref:`geohash_protocol/0::adjacent/3`  :ref:`geohash_protocol/0::adjacent_bits/4`  :ref:`geohash_protocol/0::adjacent_int/4`  :ref:`geohash_protocol/0::bounding_box/2`  :ref:`geohash_protocol/0::bounding_box_bits/3`  :ref:`geohash_protocol/0::bounding_box_int/3`  :ref:`geohash_protocol/0::cell_dimensions/3`  :ref:`options_protocol/0::check_option/1`  :ref:`options_protocol/0::check_options/1`  :ref:`geohash_protocol/0::children/2`  :ref:`geohash_protocol/0::common_prefix/3`  :ref:`geohash_protocol/0::compress/2`  :ref:`geohash_protocol/0::covering/3`  :ref:`geohash_protocol/0::covering/4`  :ref:`geohash_protocol/0::decode/2`  :ref:`geohash_protocol/0::decode_bits/3`  :ref:`geohash_protocol/0::decode_int/3`  :ref:`options_protocol/0::default_option/1`  :ref:`options_protocol/0::default_options/1`  :ref:`geohash_protocol/0::encode/3`  :ref:`geohash_protocol/0::encode_bits/3`  :ref:`geohash_protocol/0::encode_int/3`  :ref:`geohash_protocol/0::expand/2`  :ref:`geohash_protocol/0::expand_int/3`  :ref:`geohash_protocol/0::geohash_to_int/2`  :ref:`geohash_protocol/0::int_to_geohash/3`  :ref:`geohash_protocol/0::neighbors/2`  :ref:`geohash_protocol/0::neighbors_bits/3`  :ref:`geohash_protocol/0::neighbors_int/3`  :ref:`options_protocol/0::option/2`  :ref:`options_protocol/0::option/3`  :ref:`geohash_protocol/0::parent/2`  :ref:`geohash_protocol/0::polygon_covering/4`  :ref:`geohash_protocol/0::polyline_covering/4`  :ref:`geohash_protocol/0::precision/3`  :ref:`geohash_protocol/0::valid_geohash/1`  :ref:`options_protocol/0::valid_option/1`  :ref:`options_protocol/0::valid_options/1`  

.. contents::
   :local:
   :backlinks: top

Public predicates
-----------------

(no local declarations; see entity ancestors if any)

Protected predicates
--------------------

(no local declarations; see entity ancestors if any)

Private predicates
------------------

(no local declarations; see entity ancestors if any)

Operators
---------

(none)

.. seealso::

   :ref:`geohash_protocol <geohash_protocol/0>`, :ref:`geospatial <geospatial/0>`