The relationship between symbol index and showing content in Electric Navigational Chart based on GIS

Based on international standards for Electric Navigational Chart in a wide variety of standard materials, such as fairways, navigation lines, beacons, buoys, wrecks, and so on, up to 180 species, and different object has different standard display. Display symbols of some objects can be determined according to category attribute or shape attribute, but some other have to be determined based on the combination of category attribute and shape attribute. In addition, there are both objects with simple and complex boundaries so it will be very important to determine a complex corresponding relationship between objects and symbols in the symbol library of electric navigational chart. On the basis of analyzing international standards for Electric Navigational Chart, this paper analyzes the corresponding relationship between objects and symbols, proposes an indexing establishment process between symbols and objects, and implemented the indexing of the symbols in Electric Navigational Chart.