The Natural Area Code (or Universal Address) is a proprietary
geocode
A geocode is a code that represents a geographic entity ( location or 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 an ...
system for identifying an area anywhere on the
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...
, or a volume of space anywhere around the Earth. The use of thirty alphanumeric characters instead of only ten digits makes a NAC shorter than its numerical
latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north ...
/
longitude
Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek let ...
equivalent.
Two-dimensional system
Instead of numerical longitudes and latitudes, a grid with 30 rows and 30 columns - each cell denoted by the numbers 0-9 and the twenty consonants of the
Latin alphabet
The Latin alphabet or Roman alphabet is the collection of letters originally used by the ancient Romans to write the Latin language. Largely unaltered with the exception of extensions (such as diacritics), it used to write English and the ...
- is laid over the flattened globe. A NAC cell (or block) can be subdivided repeatedly into smaller NAC grids to yield an arbitrarily small area, subject to the ±1 m limitations of the
World Geodetic System
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 descr ...
(WGS) data of 1984.
A NAC represents an area on the earth—the longer the NAC, the smaller the area (and thereby, location) represented. A ten-character NAC can uniquely specify any
building
A building, or edifice, is an enclosed structure with a roof and walls standing more or less permanently in one place, such as a house or factory (although there's also portable buildings). Buildings come in a variety of sizes, shapes, and func ...
,
house
A house is a single-unit residential building. It may range in complexity from a rudimentary hut to a complex structure of wood, masonry, concrete or other material, outfitted with plumbing, electrical, and heating, ventilation, and air cond ...
, or fixed object in the world. An eight-character NAC specifies an area no larger than 25 metres by 50 metres, while a ten-character NAC cell is no larger than 0.8 metres by 1.6 metres.
Using a
base 30 positional numeral system, NAC uses an alternate method which excludes vowels and avoids potential confusion between "0" (zero) and "O" (capital "o"), and "1" (one) and "I" (capital "i"):
For example, the ten-character NAC for the centre of the city of
Brussels
Brussels (french: Bruxelles or ; nl, Brussel ), officially the Brussels-Capital Region (All text and all but one graphic show the English name as Brussels-Capital Region.) (french: link=no, Région de Bruxelles-Capitale; nl, link=no, Bruss ...
is HBV6R RG77T.
Extension to three dimensions
The full NAC system provides a third coordinate: altitude. This coordinate is the
arctangent
In mathematics, the inverse trigonometric functions (occasionally also called arcus functions, antitrigonometric functions or cyclometric functions) are the inverse functions of the trigonometric functions (with suitably restricted domains). Spe ...
of the altitude, relative to the Earth's radius, and scaled so that the zero point (000...) is at the centre of the Earth, the midpoint (H00...) is the local radius of the geoid, i.e. the Earth's surface, and the endpoint (ZZZ...) is at infinity.
For example, the three-dimensional NAC for the centre of Brussels, at ground level, is HBV6R RG77T H0000.
See also
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Universal Transverse Mercator coordinate system
The Universal Transverse Mercator (UTM) is a map projection system for assigning coordinates to locations on the surface of the Earth. Like the traditional method of latitude and longitude, it is a horizontal position representation, which means i ...
*
Quadtree
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Geohash
Geohash is a public domain geocode system invented in 2008 by Gustavo NiemeyerEvidences at the Wayback Machine:
labix.org in 2008, the G. Niemeyer's blog announcing Geohash
*an article about Geohash witnessing and citing G. Niemeyer works, befor ...
References
Further reading
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External links
NAC Geographic ProductsUse the Global Postal Code System Now
{{Geocoding-systems
Geocodes