Chain Code or Polycode

In polycode, the code symbols are independent of each other. Each digit in particular location the code represents a distinct bit of information. In given Table, a chain-structured coding scheme is presented. Numeral 3 in the third location always means axial & cross hole no matter what numbers are specified to position 1 and 2.

Advantages

Chain codes are compact and are much simple to construct & use.

Disadvantage

They may not be as detailed as hierarchical structures with the similar number of coding digits.

                                                                                                   Chain Structure