MARC21       034     Coded Cartographic Mathematical Data (R)
  Subfields: 
             $a   Category of scale
                  ** a Linear scale
                  ** b Angular scale
                  ** z Other type of scale
             $b   Constant ratio linear horizontal scale (R)
             $c   Constant ratio linear vertical scale (R)
             $d   Coordinates--westernmost longitude
             $e   Coordinates--easternmost longitude
             $f   Coordinates--northernmost latitude
             $g   Coordinates--southernmost latitude
             $h   Angular scale (R)
             $j   Declination--northern limit
             $k   Declination--southern limit
             $m   Right ascension--eastern limit
             $n   Right ascension--western limit
             $p   Equinox
             $s   G-ring latitude (R) [NEW]
             $t   G-ring longitude (R) [NEW]
             $6   Linkage

 Indic/etc.: 1st: Type of scale
             0 Scale indeterminable/No scale recorded
             1 Single scale
             2 Two or more scales [obs.]
             3 Range of scales
             2nd: Type of ring [NEW]
             # Not applicable
             0 Outer ring
             1 Exclusion ring