Research And Implementation Of Electronic Navigational Chart Spatial Database Engine

Information constructing is the basis for the implementation of information warfare on seabattelefield. The principle “The combat effectiveness depends on the degree of informationconstruction” requires highly digitized battlefield information in order to achieve fast and masstransmission. As main products of digitization of paper charts, the electronic charts have beenstandardized in content, structure and format. And applications with electronic charts asbackground have provided commanders an intuitive and clear battlefield situation view, as wellas an excellent platform for operational decision support in the form of graphics or pictures.As an important part of the electronic chart system, electronic chart spatial database playsan important role in the information construction of sea battlefield. And spatial database engineprovides capabilities for storing, querying and retrieving of spatial data; it covers thecomplexity of spatial data and strengthen capability of spatial database. To charts storage andmanagement, our existing shipboard command and control system still remains in the singlechart file management phase and lags behind the techniques of western developed countries, atthe same time, the research and application of spatial database has made great progress, but itcannot be ported into shipboard command and control system directly. As to this situation,based on the subject of “Research on technology of service-oriented command and controlsoftware in sea battlefield” in twelfth five years plan, this dissertation takes spatial databaseengine as study object, designs and implements an electronic navigational chart spatial databaseengine (ENC_SDE) in order to satisfy the special requirements of shipboard command andcontrol system.After researching on spatial data and spatial database, this dissertation introduces theprinciple, architecture, research status and developing trend of spatial database engine at first,then it discusses the standards for both data protection(S-63) and data transmission(S-57) inelectronic charts, and finally it analyzes several typical spatial data model, spatial indexingalgorithm and spatial data storing model in ENC_SDE. On this basis, this dissertation analysesthe functional requirements deeply, then it designs the architecture of the ENC_SDE and thesystem electronic chart spatial database. To meet requirements of supporting unifiedmanagement of the electronic charts spatial data and developing applications easily, a simplespatial data model retaining part of the S-57features is designed based on the object-orientedidea. To the attributes of the electronic navigational charts data organized by different scalesone by one, an optimized two level spatial indexing algorithm “grid index based on thehierarchical scales+Hilbert R-tree index based on hierarchical decomposition” is proposed anddesigned in detail. Accordingly, a spatial data storage solution and organizational structure of related files are designed to accommodate the storage and management of the massive data ofthe electronic navigational charts.This dissertation divides ENC_SDE into the import of spatial data and the access of spatialdata, and the core function modules and the key technologies are implemented throughobject-oriented approach. Finally, the experimental tests on demonstration systemENC_SED_Demo show that the data model, indexing mechanism, storage model and relatedmethods in this dissertation are feasible and efficient.