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and identification codes include:
1.38.2.1. Twenty-four longitudinal zones of 15o each, which are lettered from A through Z (omitting I
and O) eastward from the 180th meridian. Twelve bands of latitude, each 15o wide, are lettered from A
62 AFPAM11-216 1 MARCH 2001
through M (omitting I) northward from the South Pole. This combination divides the earth's surface into
288 basic 15o quadrangles, each identified by two letters. In local operations confined to a single chart or
to a single 15o quadrangle, these letters may be dropped. On small scale charts, the letter designators are
shown in large letters in the southwest corner of each 15o quadrangle. On larger scale charts, the 15o
quadrangle designators are shown along the border. When the southwest corner of a 15o quadrangle falls
in the chart area, the designators also are shown in the southwest corner of the quadrangle. The
worldwide breakdown is illustrated by Figure 1.40.
Figure 1.40. Location of 15o Quadrangle FJ, GEOREF Index.
1.38.2.2. Each basic 15o quadrangle is divided into 15 lettered 1o units eastward and 15 lettered 1o units
northward from A through Q (omitting I and O). Thus, two additional letters (four in all) identify any 1o
quadrangle in the world. Figure 1.41 illustrates the alphabetical breakdown of a 15o quadrangle.
1.38.2.3. Each 1o quadrangle is divided into 60 numbered minute units eastward and northward. Thus,
four letters and four figures identify a 1-minute quadrangle anywhere in the world. This break-down
permits location of a point within approximately 1 NM. This manner of numbering is used when the 1o
quadrangle is located; it does not vary even though the location may be west of the Greenwich meridian
or south of the equator. The GEOREF minutes of longitude always increase from west to east, and the
GEOREF minutes of latitude always increase from south to north. This is contrary to the geographic
AFPAM11-216 1 MARCH 2001 63
minutes of latitude in the Southern Hemisphere and the geographic minutes of longitude in the Western
Hemisphere.
Figure 1.41. GEOREF 15o Quadrangle FJ Breakdown into 1o.
1.38.2.4. If references of greater accuracy than 1 minute are required, each 1-minute quadrangle may be
further subdivided into decimal parts eastward and northward. Four letters and six figures define a
location of one-tenth part of a minute; four letters and eight figures to one-hundredth part of a minute,
etc.
1.38.2.5. A reference box is required on all charts overprinted by GEOREF. This box illustrates the
standard reference procedures by a fictitious example (Figure 1.42).
Figure 1.42. GEOREF Simple Reference.
64 AFPAM11-216 1 MARCH 2001
1.38.3. Sample Reference. A GEOREF reference consists of all letters and number characters arranged
in right and up reading order and in largest to smallest area sequence. References are written and read as
a continuous series of characters without spaces or punctuation. For example, FJQH1256 is the standard
reference that identifies the southwest corner of the town of Potosi, Missouri. Figure 1.43 shows the
procedure for locating this point.
Figure 1.43. To Locate FJQH 1256, Interpolate for 12 and 56.
1.38.3.1. FJ— identifies the basic 15o quadrangle.
1.38.3.2. QH— identifies the 1o quadrangle.
1.38.3.3. 12— identifies the first minute of longitude to left of the point. (This value is read from left to
right.)
1.38.3.4. 56— identifies the first minute of latitude below the point. (This value is read from bottom to
top.)
1.38.4. Special Referencing Problems. In addition to making basic area references, it is often necessary
in air operations to indicate large area and altitude. Adaptations of the world GEOREF system with
respect to these requirements follow.
1.38.4.1. To designate a rectangular or square area other than the basic area referred to in the world
GEOREF system, the following procedure is used:
1.38.4.1.1. GEOREF coordinates of the southwest corner of the area.
AFPAM11-216 1 MARCH 2001 65
1.38.4.1.2. Add the letter S denoting side, immediately following the GEOREF coordinates.
1.38.4.1.3. Add digits defining the west to east extent of the area in NM.
1.38.4.1.4. Add the letter X denoting multiplied by.
1.38.4.1.5. Add digits defining the south to north extent of the area in NM.
NOTE: The designation of the rectangular area in Figure 1.44 is EJQK2025S10X12.
1.38.4.2. To designate a circular area, reference its center by normal GEOREF coordinates, add the letter
R denoting radius and digits defining the radius in NM. Thus, the designation of the circular area in
Figure 1.44 is EJQK4550R12.
Figure 1.44. Examples of GEOREF Coordinates.
1.38.4.3. An altitude reference is designated by the letter H denoting height followed by digits, such as H
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