World Geographic Reference System


Also found in: Dictionary, Acronyms, Wikipedia.

world geographic reference system

[′wərld ¦jē·ə¦graf·ik ′ref·rəns ‚sis·təm]
(navigation)
A geographic reference system used by the U.S. Air Force for aircraft position reports, target designations, and other tactical air operations. Abbreviated georef.

World Geographic Reference System (GEOREF)

World Geographic Reference System (GEOREF)click for a larger image
A uniform position-fixing and designation system for controlling aircraft and targeting. It is better known as GEOREF. The system may be applied to any map or chart graduated in latitude and longitude regardless of projection. It is a method of expressing latitude and longitude in a form suitable for rapid reporting and plotting. The system is based on the division of the entire earth's surface into a number of quadrangles and subquadrangles. The first division is into 24 longitudinal zones, each 15° wide. They are lettered A to Z inclusive, omitting I and O, and commence eastward from the 180° meridian. Similarly, the earth is divided into 12 latitudinal bands, each 15° wide. They are lettered A to M, omitting I. The letters commence northward from the south pole. Each 15° quadrangle is further subdivided into 15 one-degree longitudinal zones and latitudinal bands. They are lettered A to Q inclusive, omitting I and O, and commence eastward and northward, respectively, from the southwest corner of the 15° quadrangle. Each of the subquadrangles is identified by means of four letters. The first two letters identify the 15° quadrangle, the third letter the one-degree zone of longitude, and the fourth letter the one-degree band of latitude. The one-degree quadrangles are further divided into 60 longitudinal zones and 60 bands of latitude—each one-minute of arc. Anyplace in this one-minute quadrangle is identified by quoting four letters and four numerals. The four letters denote the one-degree quadrangle; the first two numerals, the minutes of easting; and the remaining two numerals, the northing of the position within the one-degree quadrangle. In practice, where the risk of ambiguity with a neighboring 15° quadrangle I is unlikely, the first two letters of the reference may be dropped.