Suvarna Garge (Editor)

LOC record

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

Contents

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″N 4°53′32″E
  • 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 reference ellipsoid).
  • Postcode to LOC in DNS 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

    References

    LOC record Wikipedia