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A geocode is a
code In communications and information processing, code is a system of rules to convert information—such as a letter, word, sound, image, or gesture—into another form, sometimes shortened or secret, for communication through a communicati ...
that represents a geographic entity (
location In geography, location or place is used to denote a region (point, line, or area) on Earth's surface. The term ''location'' generally implies a higher degree of certainty than ''place'', the latter often indicating an entity with an ambiguous bou ...
or
object Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an a ...
). It is a
unique identifier A unique identifier (UID) is an identifier that is guaranteed to be unique among all identifiers used for those objects and for a specific purpose. The concept was formalized early in the development of computer science and information systems. ...
of the entity, to distinguish it from others in a
finite set In mathematics, particularly set theory, a finite set is a set that has a finite number of elements. Informally, a finite set is a set which one could in principle count and finish counting. For example, is a finite set with five elements. Th ...
of geographic entities. In general the ''geocode'' is a
human-readable In computing, a human-readable medium or human-readable format is any encoding of data or information that can be naturally read by humans, resulting in human-readable data. It is often encoded as ASCII or Unicode text, rather than as binary da ...
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.
The main examples are ISO codes:
ISO 3166-1 alpha-2 ISO 3166-1 alpha-2 codes are two-letter country codes defined in ISO 3166-1, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), to represent countries, dependent territories, and special ...
code (e.g. AF for
Afghanistan Afghanistan, officially the Islamic Emirate of Afghanistan, is a landlocked country located at the crossroads of Central Asia and South Asia. It is bordered by Pakistan to the Durand Line, east and south, Iran to the Afghanistan–Iran borde ...
or BR for
Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
), and its subdivision conventions, such as subdivision codes (e.g. AF-GHO for
Ghor province Ghōr, also spelled Ghowr or Ghur (), is one of the thirty-four provinces of Afghanistan. It is located in the western Hindu Kush in central Afghanistan, towards the northwest. The province contains eleven Districts of Afghanistan, districts, en ...
) or subdivision codes (e.g. BR-AM for Amazonas state). * ''DGG cell ID''. Identifier of a cell of a
discrete global grid A discrete global grid (DGG) is a mosaic that covers the entire Earth's surface. Mathematically it is a space partitioning: it consists of a set of non-empty regions that form a partition of the Earth's surface. In a usual grid-modeling strateg ...
: a
Geohash Geohash is a public domain geocode system invented in 2008 by Gustavo Niemeyer * * * which encodes a geographic location into a short string of letters and digits. Similar ideas were introduced by G.M. Morton in 1966. It is a hierarchical spat ...
code (e.g. ~0.023km2 cell 6vd23gq at Brazil's
centroid In mathematics and physics, the centroid, also known as geometric center or center of figure, of a plane figure or solid figure is the arithmetic mean position of all the points in the figure. The same definition extends to any object in n-d ...
) or a Plus Code (e.g. ~0.0002km2 cell 58Q8XXXX+XX within the same area). * ''Postal code''. Polygon of a postal area: a CEP code (e.g. 70040 represents a Brazilian's central area for postal distribution). The ISO 19112:2019 standard (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, use the abbreviation "GEOID" as a synonym for ''geocode''. Geocodes are mainly used (in general as an atomic data type) for
labelling Labelling or using a label is describing someone or something in a word or short phrase. For example, the label "criminal" may be used to describe someone who has broken a law. Labelling theory is a theory in sociology which ascribes labelling ...
,
data integrity Data integrity is the maintenance of, and the assurance of, data accuracy and consistency over its entire Information Lifecycle Management, life-cycle. It is a critical aspect to the design, implementation, and usage of any system that stores, proc ...
,
geotagging Geotagging, or GeoTagging, is the process of adding geographical identification metadata to various media such as a geotagged photograph or video, websites, SMS messages, QR Codes or RgSSfeeds and is a form of geospatial metadata. This data ...
and spatial indexing. In
theoretical computer science Theoretical computer science is a subfield of computer science and mathematics that focuses on the Abstraction, abstract and mathematical foundations of computation. It is difficult to circumscribe the theoretical areas precisely. The Associati ...
a ''geocode system'' is a locality-preserving hashing function.


Classification

There are some common aspects of many geocodes (or geocode systems) that can be used as classification criteria: * ''Ownership'': proprietary or free, differing by its
licence A license (American English) or licence (Commonwealth English) is an official permission or permit to do, use, or own something (as well as the document of that permission or permit). A license is granted by a party (licensor) to another part ...
s. * ''Formation'': the geocode can be originated from a name (ex. abbreviation of official name the country) or from mathematical function (
encoding In communications and Data processing, information processing, code is a system of rules to convert information—such as a letter (alphabet), letter, word, sound, image, or gesture—into another form, sometimes data compression, shortened or ...
algorithm to compress latitude-longitude). See ''geocode system'' types below (of
names A name is a term used for identification by an external observer. They can identify a class or category of things, or a single thing, either uniquely, or within a given context. The entity identified by a name is called its referent. A person ...
and of grids). * ''Hierarchy'': geocode's syntax hierarchy corresponding to the spatial hierarchy of its represented entities. A geocode system can hierarchical (
name A name is a term used for identification by an external observer. They can identify a class or category of things, or a single thing, either uniquely, or within a given context. The entity identified by a name is called its referent. A person ...
or
grid Grid, The Grid, or GRID may refer to: Space partitioning * Regular grid, a tessellation of space with translational symmetry, typically formed from parallelograms or higher-dimensional analogs ** Grid graph, a graph structure with nodes connec ...
) or non-hierarchical. * ''Covering'': global or partial. The entities (represented by the geocodes) are in all globe (e. g. geographical points) or is delimited the theme (e.g. only terrestrial areas) or by the ownership's jurisdiction (e.g. only into a country). * ''Type of the represented entity'': type of geometry. Point (the geocode can be translated to a Geo URI), grid cell (the geocode system is related with a DGG) or polygon (typically administrative boundaries delimitations). ** special hierarchical grids, with global covering and equal-area cells, can be classified as ''DGGS cell''The OGS's standard
Discrete Global Grid Systems
definition.
** some non-standard geographic entities, can be classified also by its coordinate system and elipsoid of reference (e.g. UTM). The ''de facto'' standard is the
WGS84 The World Geodetic System (WGS) is a standard used in cartography, geodesy, and satellite navigation including GPS. The current version, WGS 84, defines an Earth-centered, Earth-fixed coordinate system and a geodetic datum, and also descri ...
. * ''Scope of use'': general use vs specialized (e.g. airport geocodes).


System

The set of all geocodes used as unique identifiers of the cells of a full-coverage of the geographic surface (or any well-defined area like a country or the oceans), is a geocode system (also named ''geocode scheme''). The
syntax In linguistics, syntax ( ) is the study of how words and morphemes combine to form larger units such as phrases and sentences. Central concerns of syntax include word order, grammatical relations, hierarchical sentence structure (constituenc ...
and
semantic Semantics is the study of linguistic Meaning (philosophy), meaning. It examines what meaning is, how words get their meaning, and how the meaning of a complex expression depends on its parts. Part of this process involves the distinction betwee ...
of the geocodes are also components of the system definition: * geocode syntax: the characters that can be used, blocks of characters and its size and order. Example: country codes use two letters of the alphabet (chacacter set A-Z). The most common way to describe formally is by
regular expression A regular expression (shortened as regex or regexp), sometimes referred to as rational expression, is a sequence of characters that specifies a match pattern in text. Usually such patterns are used by string-searching algorithms for "find" ...
(e.g. / -Z). * geocode semantic: the meaning of the geocode, usually expressed by associating the code with a geographical entity type. Can be described formally is by an
ontology Ontology is the philosophical study of existence, being. It is traditionally understood as the subdiscipline of metaphysics focused on the most general features of reality. As one of the most fundamental concepts, being encompasses all of realit ...
, an UML class diagram or any Entity-relationship model.
In general the semantic can be deduced by its formation or encoding/decoding process. Example: each Geohash code can be expressed by a rectangular area in the map, and the rectangle coordinates is obtained by its decoding process. Many syntax and semantic characteristics are also summarized by classification.


Encode and decode

Any geocode can be translated from a formal (and expanded) expression of the geographical entity, or vice versa, the geocode translated to entity. The first is named encode process, the second decode. The actors and process involved, as defined by OGC,Definitions of the OGC's
Glossary of Terms
.
are: ;geocoder: A
software agent In computer science, a software agent is a computer program that acts for a user or another program in a relationship of agency. The term ''agent'' is derived from the Latin ''agere'' (to do): an agreement to act on one's behalf. Such "action on ...
that transforms the description of a geographic entity (e.g. location name or latitude/longitude coordinates), into a normalized data and encodes it as a geocode. ;geocoder service: A geocoder implemented as
web service A web service (WS) is either: * a service offered by an electronic device to another electronic device, communicating with each other via the Internet, or * a server running on a computer device, listening for requests at a particular port over a n ...
(or similar service interface), that accepts a set of geographic entity descriptors as input. The request is "sent" to the Geocoder Service, which processes the request and returns the resulting geocodes. More general services can also return geographic features (e.g.
GeoJSON GeoJSON is an open standard format designed for representing simple geographical features, along with their non-spatial attributes. It is based on the JSON format. The features include points (therefore addresses and locations), line strings ...
object) represented by the geocodes. ;geocoding: Geocoding refers to the assignment of geocodes or coordinates to geographically reference data provided in a textual format. Examples are the two letter country codes and coordinates computed from addresses.
Note: when a physical addressing schemes (street name and house number) is expressed in a standardized and simplified way, it can be conceived as geocode. So, the term
geocoding Address geocoding, or simply geocoding, is the process of taking a text-based description of a location, such as an address or the name of a place, and returning geographic coordinates, frequently latitude/longitude pair, to identify a locati ...
(used for addresses) sometimes is generalized for geocodes. In spatial indexing applications the geocode can also be translated between human-readable (e.g.
hexadecimal Hexadecimal (also known as base-16 or simply hex) is a Numeral system#Positional systems in detail, positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbo ...
) and internal (e.g. binary 64-bit unsigned integer) representations.


Systems of standard names

Geocodes like ''country codes'', city codes, etc. comes from a table of official names, and the corresponding official codes and geometries (typically polygon of administrative areas). "Official" in the context of control and consensus, typically a table controlled by a
standards organization A standards organization, standards body, standards developing organization (SDO), or standards setting organization (SSO) is an organization whose primary function is developing, coordinating, promulgating, revising, amending, reissuing, interpr ...
or governmental authority. So, the most general case is a table of ''standard names'' and the corresponding ''standard codes'' (and its official geometries). Strictly speaking, the "name" related to a geocode is a
toponym Toponymy, toponymics, or toponomastics is the study of ''wikt:toponym, toponyms'' (proper names of places, also known as place names and geographic names), including their origins, meanings, usage, and types. ''Toponym'' is the general term for ...
, and the table (e.g. toponym to standard code) is the resource for toponym resolution: is the relationship process, usually effectuated by a software agent, between a toponym and "an unambiguous spatial footprint of the same place". Any standardized system of toponym resolution, having codes or encoded abbreviations, can be used as ''geocode system''. The "resolver" agent in this context is also a ''geocoder''. Sometimes names are translated into numeric codes, to be compact or machine-readable. Since numbers, in this case, are name identifiers, we can consider "numeric names" — so this set of codes will be a kind of "system of standard names".


Hierarchical naming

In the geocode context,
space partitioning In geometry, space partitioning is the process of dividing an entire space (usually a Euclidean space) into two or more disjoint subsets (see also partition of a set). In other words, space partitioning divides a space into non-overlapping regio ...
is the process of dividing a geographical space into two or more disjoint
subset In mathematics, a Set (mathematics), set ''A'' is a subset of a set ''B'' if all Element (mathematics), elements of ''A'' are also elements of ''B''; ''B'' is then a superset of ''A''. It is possible for ''A'' and ''B'' to be equal; if they a ...
s, resulting in a
mosaic A mosaic () is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/Mortar (masonry), mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and ...
of subdivisions. Each subdivision can be partitioned again, recursively, resulting in an hierarchical mosaic. When subdivisions's names are expressed as codes, and code syntax can be decomposed into a parent-child relations, through a well-defined syntactic scheme, the geocode set configures a hierarchical system. A geocode fragment (associated to a subdivision name) can be an abbreviation, numeric or alphanumeric code. A popular example is the
ISO 3166-2 ISO 3166-2 is part of the ISO 3166 standard published by the International Organization for Standardization (ISO), and defines codes for identifying the principal subdivisions (e.g., provinces or states) of all countries coded in ISO 3166-1. Th ...
geocode system, representing country names and the names of respective
administrative subdivisions Administrative divisions (also administrative units, administrative regions, subnational entities, or constituent states, as well as many similar generic terms) are geographical areas into which a particular independent sovereign state is divi ...
separated by hyphen. For example DE is
Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
, a simple geocode, and its subdivisions (illustrated) are DE-BW for
Baden-Württemberg Baden-Württemberg ( ; ), commonly shortened to BW or BaWü, is a states of Germany, German state () in Southwest Germany, east of the Rhine, which forms the southern part of Germany's western border with France. With more than 11.07 million i ...
, DE-BY for
Bayern Bavaria, officially the Free State of Bavaria, is a state in the southeast of Germany. With an area of , it is the largest German state by land area, comprising approximately 1/5 of the total land area of Germany, and with over 13.08 million ...
, ..., DE-NW for
Nordrhein-Westfalen North Rhine-Westphalia or North-Rhine/Westphalia, commonly shortened to NRW, is a States of Germany, state () in Old states of Germany, Western Germany. With more than 18 million inhabitants, it is the List of German states by population, most ...
, etc. The scope is only the first level of the hierarchy. For more levels there are other conventions, like HASC – Hierarchical Administrative Subdivision Codes. The HASC codes are alphabetic and its fragments have constant length (2 letters). Examples: :DE.NW -
North Rhine-Westphalia North Rhine-Westphalia or North-Rhine/Westphalia, commonly shortened to NRW, is a States of Germany, state () in Old states of Germany, Western Germany. With more than 18 million inhabitants, it is the List of German states by population, most ...
. A two-level hierarchical geocode. :DE.NW.CE - Kreis
Coesfeld Coesfeld (; Westphalian language, Westphalian: ''Koosfeld'') is the capital of the Coesfeld (district), district of Coesfeld in the Germany, German state of North Rhine-Westphalia. History Coesfeld received its city rights in 1197, but was first ...
. A 3-level hierarchical geocode. Two geocodes of a ''hierarchical geocode system'' with same prefix represents different parts of the same location. For instance DE.NW.CE and DE.NW.BN represents geographically interior parts of DE.NW, the common prefix. Changing the ''subdivision criteria'' we can obtain other hierarchical systems. For example, for hydrological criteria there is a geocode system, the US's hydrologic unit code (HUC), that is a numeric representation of ''basin names'' in a hierarchical syntax schema (first level illustred). For example, the HUC 17 is the identifier of " Pacific Northwest Columbia basin"; HUC 1706 of " Lower Snake basin", a spatial
subset In mathematics, a Set (mathematics), set ''A'' is a subset of a set ''B'' if all Element (mathematics), elements of ''A'' are also elements of ''B''; ''B'' is then a superset of ''A''. It is possible for ''A'' and ''B'' to be equal; if they a ...
of HUC 17 and a superset of 17060102 ("Imnaha River").


Systems of regular grids

420px, Each cell of a regular grid is Graph labeling, labeled by a geocode. The non-global grids were the most used before the 2000s.
This ''hierarchical system of local grids'', used since the 1930s as Ordnance Survey National Grid, British National Grid, generates hierarchical geocodes. Each cell subdivides recurrently its area into a new 10x10 grid. Inspired in the classic alphanumeric grids, a
discrete global grid A discrete global grid (DGG) is a mosaic that covers the entire Earth's surface. Mathematically it is a space partitioning: it consists of a set of non-empty regions that form a partition of the Earth's surface. In a usual grid-modeling strateg ...
(DGG) is a regular
mosaic A mosaic () is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/Mortar (masonry), mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and ...
which covers the entire
Earth's surface Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
(the globe). The regularity of the mosaic is defined by the use of cells of same shape in all the grid, or "near the same shape and near same area" in a region of interest, like a country. All cells of the grid have an identifier (DGG's cell ID), and the center of the cell can be used as reference for cell ID conversion into geographical point. When a compact human-readable expression of the cell ID is standardized, it becomes a geocode. Geocodes of different ''geocode systems'' can represent the same position in the globe, with same shape and precision, but differ in
string String or strings may refer to: *String (structure), a long flexible structure made from threads twisted together, which is used to tie, bind, or hang other objects Arts, entertainment, and media Films * ''Strings'' (1991 film), a Canadian anim ...
-length, digit-alphabet, separators, etc. Non-global grids also differ by scope, and in general are geometrically optimized (avoid overlaps, gaps or loss of uniformity) for the local use.


Hierarchical grids

Each cell of a grid can be transformed into a new local grid, in a recurring process. In the illustrated example, the cell TQ 2980 is a sub-cell of TQ 29, that is a sub-cell of TQ. A system of geographic regular
grid reference A projected coordinate systemalso called a projected coordinate reference system, planar coordinate system, or grid reference systemis a type of spatial reference system that represents locations on Earth using Cartesian coordinate system, Car ...
s is the base of a ''hierarchical geocode system''. Two geocodes of a ''hierarchical geocode grid system'' can use the prefix rule: geocodes with same prefix represents different parts of the same broader location. Using again the side illustration: TQ 28 and TQ 61 represents geographically interior parts of TQ, the common prefix. Hierarchical geocode can be split into keys. The
Geohash Geohash is a public domain geocode system invented in 2008 by Gustavo Niemeyer * * * which encodes a geographic location into a short string of letters and digits. Similar ideas were introduced by G.M. Morton in 1966. It is a hierarchical spat ...
6vd23gq is the key q of the cell 6vd23g, that is a cell of 6vd23 (key g), and so on, per-digit keys. The OLC 58PJ642P is the key 48 of the cell 58PJ64, that is a cell of 58Q8 (key 48), and so on, two-digit keys. In the case of OLC there is a second key schema, after the + separator: 58PJ642P+48 is the key 2 of the cell 58PJ642P+4. It uses two key schemas. Some geocodes systems (e.g. S2 geometry) also use initial prefix with non-hierarchical key schema. In general, as technical and non-compact optional representation, geocode systems (based on hierarchical grids) also offer the possibility of expressing their cell identifier with a fine-grained schema, by longer path of keys. For example, the Geohash 6vd2, which is a
base32 Base32 is an encoding method based on the Radix, base-32 numeral system. It uses an alphabet of 32 Numerical digit, digits, each of which represents a different combination of 5 bits (25). Since base32 is not very widely adopted, the question of no ...
code, can be expanded to base4 0312312002, which is also a schema with per-digit keys. Geometrically, each Geohash cell is a rectangle that subdivides space recurrently into 32 new rectangles, so, base4 subdividing into 4, is the encoding-expansion limit. The uniformity of shape and area of cells in a grid can be important for other uses, like
spatial statistics Spatial statistics is a field of applied statistics dealing with spatial data. It involves stochastic processes (random fields, point processes), sampling, smoothing and interpolation, regional ( areal unit) and lattice ( gridded) data, poin ...
. There are standard ways to build a grid covering the entire globe with cells of equal area, regular shape and other properties: Discrete Global Grid System (DGGS) is a series of discrete global grids satisfying all standardized requirements defined in 2017 by the OGC. When human-readable codes obtained from cell identifiers of a DGGS are also standardized, it can be classified as ''DGGS based geocode system''.


Name-and-grid systems

There are also mixed systems, using a syntactical partition, where for example the first part (code prefix) is a name-code and the other part (code suffix) is a grid-code. Example: : Mapcode entrance to the elevator of the
Eiffel Tower The Eiffel Tower ( ; ) is a wrought-iron lattice tower on the Champ de Mars in Paris, France. It is named after the engineer Gustave Eiffel, whose company designed and built the tower from 1887 to 1889. Locally nicknamed "''La dame de fe ...
in Paris is FR-4J.Q2, where FR is the name-code and 4J.Q2 is the grid-code. Semantically France is the context, to obtain its local grid. For
mnemonic A mnemonic device ( ), memory trick or memory device is any learning technique that aids information retention or retrieval in the human memory, often by associating the information with something that is easier to remember. It makes use of e ...
coherent semantics, in fine-grained geocode applications, the mixed solutions are most suitable.


Shortening grid-based codes by context

Any ''geocode system'' based on regular grid, in general is also a shorter way to express a latitudinal/longitudinal coordinate. But a geocode with more than 6 characters is difficult for remember. On the other hand, a geocode based on standard name (or abbreviation or the complete name) is easier to remember. This suggests that a "mixed code" can solve the problem, reducing the number of characters when a name can be used as the "context" for the grid-based geocode. For example, in a book where the author says "all geocodes here are contextualized by the chapter's city". In the chapter about Paris, where all places have a Geohash with prefix u09, that code can be removed —. For instance Geohash u09tut can be reduced to tut, or, by an explicit code for context "FR-Paris tut". This is only possible when the context resolution (e.g. translation from "FR-Paris" to the prefix u09) is well-known. In fact a methodology exists for hierarchical grid-based geocodes with non-variable size, where the code prefix describes a broader area, which can be associated with a name. So, it is possible to shorten by replacing the prefix to the associated context. The most usual context is an official name. Examples: The examples of the ''Mixed reference'' column are significantly easier than remembering ''DGG code'' column. The methods vary, for example OLC can be shortened by elimination of its first four digits and attaching a suitable sufficiently close locality. When the mixed reference is also short (9 characters in the second example) and there are a syntax convention to express it (suppose CP‑PR~bgxed), this convention is generating a new name-and-grid geocode system. This is not the case of the first example because, strictly speaking, "Cape Verde, Praia" is not a code. To be both, a name-and-grid system and also a mixed reference convention, the system must be reversible. Pure name-and-grid systems, like Mapcode, with no way to transform it into a global code, is not a mixed reference, because there is no algorithm to transform the mixed geocode into a grid-based geocode.


Cataloged examples


In use, general scope

Geocodes in use and with general scope:


In use, alternative address

Geocodes can be used in place of official street names and/or house numbers, particularly when a given location has not been assigned an address by authorities. They can also be used as an "alternative address" if it can be converted to a Geo URI. Even if the geocode is not the official designation for a location, it can be used as a "local standard" to allow homes to receive deliveries, access emergency services, register to vote, etc.


In use, postal codes

Geocodes in use, as
postal codes A postal code (also known locally in various English-speaking countries throughout the world as a postcode, post code, PIN or ZIP Code) is a series of letters or numerical digit, digits or both, sometimes including spaces or punctuation, inclu ...
. A geocode recognized by
Universal Postal Union The Universal Postal Union (UPU, ) is a specialized agency of the United Nations (UN) that coordinates postal policies among member nations and facilitates a uniform worldwide postal system. It has 192 member states and is headquartered in Be ...
and adopted as "official postal code" by a
country A country is a distinct part of the world, such as a state, nation, or other political entity. When referring to a specific polity, the term "country" may refer to a sovereign state, state with limited recognition, constituent country, ...
, is also a valid postal code. Not all postal codes are geographic, and for some postal code systems, there are codes that are not geocodes (e.g. in UK system). Samples, not a complete list:


In use, telephony and radio

Geocodes in use for telephony or radio broadcasting scope: * ITU-R country codes * ITU-T country calling codes * ITU-T mobile calling codes *
Maidenhead Locator System The Maidenhead Locator System (a.k.a. QTH Locator and IARU Locator) is a geocode system A geocode is a code that represents a geographic entity (location or Geographical feature, object). It is a unique identifier of the entity, to distinguis ...
(used by amateur radio operators) * Marsden Squares


In use, others

Geocodes in use and with specific scope:


Historical or less widely used


Other examples

Other geocodes: * ''S2'': a geocoding scheme using
spherical geometry 300px, A sphere with a spherical triangle on it. Spherical geometry or spherics () is the geometry of the two-dimensional surface of a sphere or the -dimensional surface of higher dimensional spheres. Long studied for its practical applicati ...
and the space-filling
Hilbert curve The Hilbert curve (also known as the Hilbert space-filling curve) is a Geometric continuity, continuous fractal curve, fractal space-filling curve first described by the German mathematician David Hilbert in 1891, as a variant of the space-filling ...
, developed at
Google Google LLC (, ) is an American multinational corporation and technology company focusing on online advertising, search engine technology, cloud computing, computer software, quantum computing, e-commerce, consumer electronics, and artificial ...
* ''H3'': Hexagonal Hierarchical Spatial Index a geocoding scheme initially developed at Uber source code available and documented at h3geo * ''Munich Orientation Convention'': converts lat/lon to metrical monopolar codes for targets, crossings, stations, stop points, bridges, tunnels, towns, islands, volcanoes, highway exits etc. * ''SALB'' (Second Administrative Level Boundaries), by UN * OpenPostcode, opensource global algorithm (local adaptations as Irish & Hong Kong postcodes). * WOEID *
OpenStreetMap OpenStreetMap (abbreviated OSM) is a free, Open Database License, open geographic database, map database updated and maintained by a community of volunteers via open collaboration. Contributors collect data from surveying, surveys, trace from Ae ...
shortlink, used as a short permanent link to map locations * Quarter Degree Grid Cells * NAC (patended), area codes (area can be indefinitely small) * GEOID, the name of
United States Census Bureau The United States Census Bureau, officially the Bureau of the Census, is a principal agency of the Federal statistical system, U.S. federal statistical system, responsible for producing data about the American people and American economy, econ ...
geographic identifiers. * In the United States, the American National Standards Institute (ANSI) Codes are often used. ANSI INCITS 446-2008 is entitled "Identifying Attributes for Named Physical and Cultural Geographic Features (Except Roads and Highways) of the United States, Its Territories, Outlying Areas, and Freely Associated Areas, and the Waters of the Same to the Limit of the Twelve-Mile Statutory Zone". *
National Topographic System The National Topographic System or NTS is the system used by Natural Resources Canada for providing general purpose topographic maps of the country. NTS maps are available in a variety of scales, the standard being 1:50,000 and 1:250,000 scales. ...
in Canada


Other standards

Some standards and name servers include: ISO 3166, FIPS, INSEE, Geonames, IATA and
ICAO The International Civil Aviation Organization (ICAO ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international sch ...
. A number of commercial solutions have also been proposed: * WOEID (Where on Earth IDentifier) is a unique 32-bit reference identifier that identifies any feature on Earth. * NAC Locator provides a universal geocoding address for all locations on the planet.


See also

*
Census tract A census tract, census area, census district or meshblock is a geographic region defined for the purpose of taking a census. Sometimes these coincide with the limits of cities, towns or other administrative areas and several tracts commonly exis ...
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Geolocation Geopositioning is the process of determining or estimating the geographic position of an object or a person. Geopositioning yields a set of Geographic coordinate system, geographic coordinates (such as latitude and longitude) in a given map datum ...
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Geotagging Geotagging, or GeoTagging, is the process of adding geographical identification metadata to various media such as a geotagged photograph or video, websites, SMS messages, QR Codes or RgSSfeeds and is a form of geospatial metadata. This data ...
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Geographic information retrieval Geographic information retrieval (GIR) or geographical information retrieval systems are search tools for searching the Web, enterprise documents, and mobile local search that combine traditional text-based queries with location querying, such a ...
* Global Navigation Grid Code (China geocode?) * ISO 6709, standard representation of geographic point location by coordinates * Place code * Unique Property Reference Number * Unique Street Reference Number


References


External links

* {{Geocoding-systems for all types of data and information that is used to make a decision about a specific set of information and the information it provides for it