In the
Domain Name System
The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks. It associates various information with domain names assigned to ...
, a LOC record (experimental ) is a means for expressing geographic location information for a
domain name
A domain name is a string that identifies a realm of administrative autonomy, authority or control within the Internet. Domain names are often used to identify services provided through the Internet, such as websites, email services and more. As ...
.
It contains
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 descr ...
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 pol ...
,
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 letter l ...
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 ...
(
ellipsoidal height
Geodetic coordinates are a type of curvilinear orthogonal coordinate system used in geodesy based on a ''reference ellipsoid''.
They include geodetic latitude (north/south) , ''longitude'' (east/west) , and ellipsoidal height (also known as geod ...
) information together with host/
subnet
A subnetwork or subnet is a logical subdivision of an IP network. Updated by RFC 6918. The practice of dividing a network into two or more networks is called subnetting.
Computers that belong to the same subnet are addressed with an identical ...
physical size and location accuracy. This information can be queried by other computers connected to the Internet.
Record format
The LOC record is expressed in a master file in the following format:
LOC ( d1 1_[s1__d2_[m2_[s2.html"_;"title="1.html"_;"title="1_[s1">1_[s1__d2_[m2_[s2">1.html"_;"title="1_[s1">1_[s1__d2_[m2_[s2
_____________________________alt["m".html" ;"title="1">1_[s1__d2_[m2_[s2.html" ;"title="1.html" ;"title="1 [s1">1 [s1 d2 [m2 [s2">1.html" ;"title="1 [s1">1 [s1 d2 [m2 [s2
alt["m"">1">1_[s1__d2_[m2_[s2.html" ;"title="1.html" ;"title="1 [s1">1 [s1 d2 [m2 [s2">1.html" ;"title="1 [s1">1 [s1 d2 [m2 [s2
alt["m"[siz["m"] [hp["m"]
[vp["m" )
(The parentheses are used for multi-line data as specified in RFC 1035, section 5.1.)
where:
d1: [0 .. 90] (degrees latitude)
d2: .. 180 (degrees longitude)
m1, m2: .. 59 (minutes latitude/longitude)
s1, s2: .. 59.999 (seconds latitude/longitude)
alt: 100000.00 .. 42849672.95BY .01 (altitude in meters)
siz, hp, vp: .. 90000000.00(size/precision in meters)
An example DNS LOC resource record
* statdns.net for the
coordinates
In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space. The order of the coordinates is sig ...
:
LOC record statdns.net. IN LOC 52 22 23.000 N 4 53 32.000 E -2.00m 0.00m 10000m 10m
Altitude for Geosynchronous Earth Satellites
The altitude range provides the following:
* DNS altitude range
100000.00 .. 42849672.95 This range can be easily stored in 4 bytes.
* Maximum altitude is 42,849.67295 km. Which is large enough to store the altitude of a circular geosynchronous orbit (i.e. approximately 35,790 km above mean sea level).
* Maximum depth of 100 km below earth surface (approximated by 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 descr ...
reference ellipsoid
An Earth ellipsoid or Earth spheroid is a mathematical figure approximating the Earth's form, used as a reference frame for computations in geodesy, astronomy, and the geosciences. Various different ellipsoids have been used as approximations ...
).
UK Postcode to DNS LOC record using find.me.uk
You can look up the LOC record for any UK postcode, e.g.:
$
dig loc SW1A2AA.find.me.uk
SW1A2AA.find.me.uk. 2592000 IN LOC 51 30 12.748 N 0 7 39.612 W 0.00
See also
*
List of DNS record types
This list of DNS record types is an overview of resource records (RRs) permissible in zone files of the Domain Name System
The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resour ...
*
Geo (microformat)
Geo is a microformat used for marking up WGS84 geographical coordinates (latitude;longitude) in (X)HTML. Although termed a "draft" specification, this is a formality, and the format is stable and in widespread use; not least as a sub-set of th ...
*
Geolocation
Geopositioning, also known as geotracking, geolocalization, geolocating, geolocation, or geoposition fixing, is the process of determining or estimating the geographic position of an object.
Geopositioning yields a set of Geographic coordinate s ...
*
Geolocation API
The W3C Geolocation API is an effort by the World Wide Web Consortium (W3C) to standardize an interface to retrieve the geographical location information for a client-side device. It defines a set of objects, ECMAScript standard compliant, that e ...
*
ICBM address
ICBM (intercontinental ballistic missile) address or missile address is hacker slang for one's longitude and latitude (preferably to seconds-of-arc accuracy) when placed in a signature or another publicly available file.
Origin
The form that u ...
*
ISO 6709
ISO 6709, ''Standard representation of geographic point location by coordinates'', is the international standard for representation of latitude, longitude and altitude for geographic point locations.
The first edition (ISO 6709:1983) was develo ...
References
*
Wikipedia:WikiProject Geographical coordinates The Wikipedia location resource.
Sites supporting DNS LOC* - How latitude and longitude are stored in a DNS record.
* Chapter 3.4.2: Text/directory MIME type GEO
* Section 6.5.2: GEO (obsoleted , updated by )
{{DEFAULTSORT:Loc Record
DNS record types
Internet geolocation