Aeronautic map nomenclature (ANK)

The nomenclature  code structure looks like:

        9 - 9 - 99 - 99

   1   2   34   56

  1 symbol. Means the block, accepts values from 1 up to 3, where:

1 – the main block(mainframe),

2 - the northern polar block,

3 - the southern polar block.

  2 symbol . Means the scale, accepts values 1,2, where :

1 - scale  1 : 2 000 000,

2 - scale  1 : 4 000 000.

  3, 4 symbols. Means the "Latitude zone" or Row number, accepts values

From 01 up to 12.

  5, 6 symbols. Designates(Means) the "Longitude zone" or Column  number, accepts values

From 01 up to 20.

Nomenclature example.

The mainframe of the scale  1 : 2 000 000 :   1-2-10-05