LOC record

From Wikipedia, the free encyclopedia

The LOC record (RFC1876) is a means for expressing location information in the Domain Name System. It contains WGS84 Latitude, Longitude and Altitude information together with host/subnet physical size and location accuracy. This information can be queried by other computers connected to the internet.

1 Record format
2 An example DNS LOC resource record
3 Altitude for Geosynchronous Earth Satellites
4 See also
5 References

[edit] 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)

[edit] An example DNS LOC resource record

yahoo.com in wiki coordinates: 37°23.5150′N 121°59.3167′W
LOC record [1]

yahoo.com.   IN LOC   37 23 30.900 N 121 59 19.000 W 7.00m 100.00m 100.00m 2.00m

[edit] 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.