The Watermark Hiding Method and Watermark Extracting Method of Vector Map Data in Geometric Information System

摘要

PURPOSE: A water mark hiding method in vector map data of a geographical information system and a water mark detecting method are provided to detect a water mark hidden in the vector map data in an encoding and a decoding area without decoding the data. CONSTITUTION: A geographic information system extracts record information including attributes of polyline and polygon from each layer(S1300). The geographical information system encodes the extracted record information(S1400). The geographical information system executes an adaptive water marking process by using an Euclid distance(S1500). The geographical information system stores the vector map data including the water mark and information for extracting the water mark(S1600). [Reference numerals] (AA) Start; (BB) End; (S1000) Hiding a water mark; (S1100) Loading vector map data; (S1200) Selecting a layer and grouping; (S1300) Extracting record information including attributes of polyline and polygon from each selected layer; (S1400) Compression-based encoding each record information; (S1500) Adaptively water marking using an Euclid distance; (S1510) Calculating the average Euclid distance of all polyline and polygon in layers(MED_ALL); (S1520) Calculating the minimum value(l_min) and the maximum value(l_max) of each inserting section into which the water mark is to be inserted; (S1530) Determining the size of each inserting section into which the water mark is to be inserted; (S1540) Adjusting the size of each inserting section according to the bit value of the water mark; (S1550) Hiding the water mark by inserting the water mark into each inserting section with adjusted size; (S1600) Storing vector map data including the hidden water mark and information required for extracting the water mark