LOC record

In the Domain Name System, a LOC record (experimental RFC   1876) ^[1] is a means for expressing geographic location information for a domain name.

It contains WGS84 Latitude, Longitude and Altitude (ellipsoidal height) information together with host/subnet 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:

⟨owner⟩⟨TTL⟩⟨class⟩ LOC ( d1 [m1 [s1]] {"N"|"S"} d2 [m2 [s2]]                            {"E"|"W"} 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:     [0 .. 180]           (degrees longitude)     m1, m2: [0 .. 59]            (minutes latitude/longitude)     s1, s2: [0 .. 59.999]        (seconds latitude/longitude)     alt:    [-100000.00 .. 42849672.95] BY .01 (altitude in meters)     siz, hp, vp: [0 .. 90000000.00] (size/precision in meters) 

An example DNS LOC resource record

• statdns.net for the coordinates: 52°22′23″N4°53′32″E / 52.37306°N 4.89222°E / 52.37306; 4.89222 (StatDNS.net LOC record)

statdns.net.INLOC522223.000N45332.000E-2.00m0.00m10000m10m

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 reference ellipsoid).

See also

• List of DNS record types
• Geo (microformat)
• Geolocation
• Geolocation API
• ICBM address
• ISO 6709

References

1. "A Means for Expressing Location Information in the Domain Name System".

• Wikipedia:WikiProject Geographical coordinates The Wikipedia location resource.
• Sites supporting DNS LOC
• RFC  1876 - How latitude and longitude are stored in a DNS record.
• RFC  2426 Chapter 3.4.2: Text/directory MIME type GEO
• RFC  6350 Section 6.5.2: GEO (obsoleted RFC  2426, updated by RFC  6868)