Research And Application Of Electronic Chart System Data-integrating Technology

Ocean navigation is a global transport network. With the development of China's ocean sailing, an electronic chart display and information system (ECDIS) based on the international standard is urgently needed. The charts on the S-57 international standard should be used in the system to ensure the electronic charts cover global sea. The charts on the MVCF standard are used in China's ECDIS. In order to make these systems upgrade smoothly, new electronic chart systems are needed which is based on the international standard and must be able to integrate both the S-57 and the MVCF charts. To solve these issues, a method of electronic chart system's data integration based on the format conversion is proposed in this paper.First, characteristics of the spatial data, the spatial data model, the spatial data structure, and vector charts are studied deeply, which provide the basic foundation for the data integration and the data conversion among charts of different formats.Second, by analyzing various methods of spatial data integration and the frames of domestic electronic chart systems, two feasible schemes of chart data integration are proposed. Through a comprehensive comparison, the scheme of data integration based on the data format conversion is chosen.Third, the differences between the MVCF and the S-57 standards are studied and discussed. Based on this, the model of chart data conversion from the MVCF to the S-57 is designed and three key techniques in data conversion are described.The conversion of reference frames are studied deeply. The algorithm of coordinate conversion from BJ-54 to WGS-84 and the Mercator's project algorithm are implemented using C++. The conversion algorithm from the vector data structure without the topology used by the MVCF to the vector data structure with topology used by the S-57 is implemented using C++. The conversion scheme and methods of MVCF charts to S-57 charts are proposed. And the corresponding conversion table of MVCF charts to S-57 charts is constructed based on the geographical perceiving and the geographical abstract.Finally, the chart data converter from the MVCF to the S-57 under the Windows platform is designed and integrated into the electronic chart system. The integration of S-57 charts and MVCF charts is implemented.