Editing Geocode (section)

{{short description|Code that represents a geographic entity (location or object)}}
{{distinguish|Address geocoding}}

A  '''geocode''' is a [[code]] that represents a geographic entity ([[location]] or [[Geographical feature|object]]). It is a [[unique identifier]] of the entity, to distinguish it from others in a [[finite set]]  of geographic entities. In general the ''geocode'' is a  [[human-readable]] and short identifier.

Typical geocodes (in bold) and entities represented by it:

* ''Country code'' and subdivision code. Polygon of the administrative boundaries of a country or a subdivision. <br />The main examples are ISO codes:  [[ISO 3166-1 alpha-2]] code (e.g. '''<code>AF</code>''' for [[Afghanistan]] or '''<code>BR</code>''' for [[Brazil]]), and its subdivision conventions, such as [[ISO 3166-2:AF|{{mono|1=AF}} subdivision codes]]  (e.g. '''<code>AF-GHO</code>''' for [[Ghor province]]) or [[ISO 3166-2:BR|{{mono|1=BR}} subdivision codes]] (e.g. '''<code>BR-AM</code>''' for [[Amazonas (Brazilian state)|Amazonas state]]).

*  ''DGG cell ID''. Identifier of a cell of a [[discrete global grid]]:   a [[Geohash]] code (e.g. ~0.023{{nbsp}}km<sup>2</sup> cell '''<code>6vd23gq</code>''' at Brazil's [[Geographical centre|centroid]]) or a [[Open Location Code|Plus Code]] (e.g. ~0.0002{{nbsp}}km<sup>2</sup> cell '''<code>58Q8XXXX+XX</code>''' within the same area).

* ''Postal code''. Polygon of a [[postal code|postal area]]: a [[Código de Endereçamento Postal|CEP]] code (e.g. '''<code>70040</code>''' represents a Brazilian's central area for postal distribution).

The ISO&nbsp;19112:2019 standard<ref>"ISO 19112:2019 — Geographic information — Spatial referencing by geographic identifiers", "Section 3.1.2 — Geographic identifier", https://www.iso.org/standard/70742.html</ref> (section 3.1.2) adopted the term "geographic identifier" instead ''geocode'', to encompass long labels: ''spatial reference in the form of a label or code that identifies a location''. For example, for ISO, the country name “People's Republic of China” is a label. Some authors, such as the United States Census Bureau<ref>"Understanding Geographic Identifiers (GEOIDs)", https://www.census.gov/programs-surveys/geography/guidance/geo-identifiers.html</ref>, use the abbreviation "GEOID" as a synonym for ''geocode''.

Geocodes are mainly used  (in general as an [[Primitive data type|atomic data type]]) for [[labelling]], [[data integrity]], [[geotagging]] and [[Spatial database#Spatial index|spatial indexing]].

In [[theoretical computer science]] a  ''geocode system'' is a [[Locality-sensitive hashing#Locality-preserving hashing|locality-preserving hashing function]].