摘要 |
A map of an entire region is divided into sections of a square of 900'', each of which is further divided into blocks of a square of 30'', each of which is further divided into units of a square of 1'', so that a region on the map can be hierarchically designated. Each section is defined with section codes of three figures; each block is defined with block codes of three figures in accordance with its relative positional relation in the section; and each unit is defined with unit codes of three figures in accordance with its relative positional relation in the block, so that each unit can be completely differentiated with an intrinsic code of nine figures composed of those three kinds of codes. As to the section code composing the intrinsic code corresponding to the predetermined region, moreover, a number of significant digits is reduced by assigning a lower number in the code system, so that the manual operations of inputting the intrinsic code of the predetermined region can be lightened.
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