ISO 6709, ''Standard representation of geographic point location by coordinates'', is the

international standard international standard is a technical standard developed by one or more international standards organization, standards organizations. International standards are available for consideration and use worldwide. The most prominent such organization ...

for representation of

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 ...

and

altitude Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...

for geographic point locations. The first edition (ISO 6709:1983) was developed by

ISO/IEC JTC 1 ISO/IEC JTC 1, entitled "Information technology", is a joint technical committee (JTC) of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). Its purpose is to develop, maintain and pr ...

/SC 32. Later the standard was transferred to ISO/TC211, ''Geographic information/Geomatics'' in 2001. The committee completely revised the second edition (ISO 6709:2008). There was a short technical corrigendum (ISO 6709:2008/Cor 1:2009) released in 2009. The second edition consists of a main part and eight annexes (Annexes A through H). The main part and Annexes A and C give encoding-independent general rules to define items to specify geographic point(s). Annex D suggests a display style for human interface. Annexes F and G suggest styles of

XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ...

expression. Annex H suggests string expression, which supersedes the first edition of the standard.

General rules

Items

A geographical point is specified by the following four items: * First horizontal coordinate (''ϕ'' or ''y''), such as latitude (negative number south of equator and positive north of equator) * Second horizontal coordinate (''λ'' or ''x''), such as longitude (negative values west of Prime Meridian and positive values east of Prime Meridian) * Vertical coordinate, i.e. height or depth (optional) * Identification of

coordinate reference system A spatial reference system (SRS) or coordinate reference system (CRS) is a framework used to precisely measure locations on the surface of the Earth as coordinates. It is thus the application of the abstract mathematics of coordinate systems and ...

(CRS) (optional) The first three items are numerical values called coordinates. The CRS gives the relationship between the coordinates and a point on the earth. The identification of CRS could be a full description of properties defined in ISO 19111; only an identifier given by some registry (such as EPSG) is used in most cases, since only such identification is enough for most information exchange purposes.

Order, sign, and units

Order, positive direction, and units of coordinates are supposed to be defined by the CRS. When CRS identification is missing, the data must be interpreted by the following conventions: * Latitude comes before longitude * North latitude is positive * East longitude is positive * Fraction of degrees ( decimal degrees) is preferred in digital data exchange, while

sexagesimal Sexagesimal, also known as base 60 or sexagenary, is a numeral system with sixty as its base. It originated with the ancient Sumerians in the 3rd millennium BC, was passed down to the ancient Babylonians, and is still used—in a modified form ...

notation is tolerated for compatibility There is no such interpretation rule for vertical coordinates.

Representation at the human interface (Annex D)

When there is no guideline given from the user community, the following styles are suggested: # Coordinate values (latitude, longitude, and altitude) should be delimited by spaces. # The decimal point is a part of the value, thus must usually be configured by the operating system. # Multiple locations should be represented by multiple lines. # Latitude and longitude should be displayed by sexagesimal fractions (i.e. minutes and seconds). # When minutes and seconds are less than ten, leading zeroes should be shown. # Degree, minutes and seconds should be followed by the symbols ° ( U+00B0), ′ ( U+2032), and ″ ( U+2033), without spaces between the number and symbol. # North and south latitudes should be indicated by ''N'' and ''S'' following immediately after the digits. # East and west longitudes should be indicated by ''E'' and ''W'' following immediately after the digits. # Units of elevation or depth should be given by symbols, immediately after the digits. # Elevation below reference level or depth above reference level should be indicated by a minus sign − (U+2212). Examples: * 50°40′46.461″N 95°48′26.533″W 123.45m * 50°03′46.461″S 125°48′26.533″E 978.90m The standard does not specify how coordinates at the

equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can also ...

prime meridian A prime meridian is an arbitrary meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great ...

or antimeridian should be written.

XML representation (Annex F)

The XML representation based on the conceptual model of Annex C uses XML namespace http://www.isotc211.org/2006/gpl. However, there is no published XML schema at the time of writing (August 2011). 35.89421911 139.94637467

String expression (Annex H)

A string expression of a point consists of latitude, longitude, height or depth, CRS identifier, and trailing solidus (/) without any delimiting character. When height or depth is used, there must be CRS identifier.

Latitude

Latitude is a number preceded by a sign character. A plus sign (+) denotes northern hemisphere or the equator, and a minus sign (-) denotes southern hemisphere. The integer part of the number is a fixed length. The number of digits in that part indicates the units, thus leading zero(es) must be filled when necessary. The fractional part must have the appropriate number of digits to represent the required precision of the coordinate.

Longitude

Longitude is a number preceded by a sign character. A plus sign (+) denotes east longitude or the

, and a minus sign (-) denotes west longitude or 180° meridian (opposite of the prime meridian). Rules about the number of digits are the same as for latitude.

Height or depth

* When height or depth is present, CRS identifier must follow. * Positive direction and units are defined by CRS.This is different from the 1983 edition. * Negative number does not necessarily mean position below reference level. * Positive is up for height, down for depth.

CRS identifier

The CRS identifier begins with "CRS". There are three styles: # When a registry provides online resolver, CRS<''url''> # When a registry is offline, CRSr''egistry'':''crsid'' # When the data creator provides full definition of CRS using ISO 19111, CRS<''CRSID''> The example of original Annex H always use "CRSWGS_84".

Examples

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

+00-025/ *

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

+46+002/ **

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. Si ...

+48.52+002.20/ ***

Eiffel Tower The Eiffel Tower ( ; french: links=yes, tour Eiffel ) 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. Locally nicknamed ...

+48.8577+002.295/ *

Mount Everest Mount Everest (; Tibetan: ''Chomolungma'' ; ) is Earth's highest mountain above sea level, located in the Mahalangur Himal sub-range of the Himalayas. The China–Nepal border runs across its summit point. Its elevation (snow hei ...

+27.5916+086.5640+8850CRSWGS_84/ *

North Pole The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface. It is called the True North Pole to distinguish from the Ma ...

+90+000/ *

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the conti ...

+00-160/ *

South Pole The South Pole, also known as the Geographic South Pole, Terrestrial South Pole or 90th Parallel South, is one of the two points where Earth's axis of rotation intersects its surface. It is the southernmost point on Earth and lies antipod ...

-90+000+2800CRSWGS_84/ *

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

+38-097/ **

New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

+40.75-074.00/ ***

Statue of Liberty The Statue of Liberty (''Liberty Enlightening the World''; French: ''La Liberté éclairant le monde'') is a colossal neoclassical sculpture on Liberty Island in New York Harbor in New York City, in the United States. The copper statue, ...

+40.6894-074.0447/

Notes

External links

Standards

Catalogue entry for ISO 6709:2008

final draft of ISO 6709:2008

Profile by W3C GeoXG

Implementations

Point Location 6709 - an open-source Java parser and formatter

Point Location 6709 - an open-source JavaScript implementation

C# Implementation at Codeplex

Objective-C Implementation
{{ISO standards #06709 Geographic coordinate systems ISO/TC 211