MARC21       006e'05-06  Projection
     Values: 
             ##   Projection not specified
             aa   Aitoff
             ab   Gnomic
             ac   Lambert's azimuthal equal area
             ad   Orthographic
             ae   Azimuthal equidistant
             af   Stereographic 
             au   Azimuthal, specific type unknown
             ba   Gall
             bb   Goode's homolographic
             bc   Lambert's cylindrical equal area
             bd   Mercator
             be   Miller
             bf   Mollweide
             bg   Sinusoidal
             bh   Transverse Mercator
             bi   Gauss-Kruger
             bu   Cylindrical, specific type unknown
             ca   Alber's equal area
             cb   Bonne
             cc   Lambert's conformal conic
             cp   Polyconic
             cu   Conic, specific type unknown
             da   Armadillo
             db   Butterfly
             dc   Eckert
             dd   Goode's homolosine
             de   Miller's bipolar oblique conformal conic
             df   Van Der Grinten
             dg   Dimaxion
             dh   Cordiform
             zz   Other