GEOMETRIC INFORMATION HIDING METHOD AND GEOMETRIC INFORMATION EXTRACTING METHOD FOR COPYRIGHT PROTECTION OF NG I ASC II FORMAT BASED DIGITAL MAP, AND RECORDING MEDIUMS STORING HIDING AND EXTRACTING PROGRAMS OF GEOMETRIC INFORMATION

摘要

PURPOSE: A method for concealing geographic information for protecting copyright of digital map based on ngi asci format capable of increasing invisibility and tenacity of digital map which geographic information is concealed are provided to apply polygons which average surface is controlled to relevant layer. CONSTITUTION: A selected polygons is classified into a plurality of polygons groups corresponding to the bit numbers of watermark(1600). Based on surface value of polygons included in the plurality of polygon groups, a second average surface value is calculated about the plurality of polygon groups(1700). The second average surface value is controlled about the plurality of polygon groups according to the bit value of the watermark corresponding to the plurality of polygon groups(1800). The polygons of the plurality of groups which the second average surface value is controlled are applied to the selected layer(1900).