| Since late 1970s, Researches related to new media for charts were getting popular and in 1980s, electronic charts appeared. The rapid development of computer technology not only promotes the continuous progresses of the electronic chart technology, but also provides the necessary hardware platforms to electronic charts. ECDIS (Electronic Chart Display and Information System) can provide seafarers with a vivid chart plane. It also can greatly facilitate the work of navigation such as route planning, position fixing, ranging, etc. Through the interface it offers, navigation equipments such as Radar, GPS, Compass and Satellite navigation system, etc can be accessed into ECDIS. So, ECDIS is sure to become a significant component of new combined navigation system.As the basic of electronic chart application system, ECDB (Electronic Chart Database) decides the function and performance of the system. There are massive chart data stored in ECDB, how to organize and manage chart data rationally is the key of the performance of ECDIS. Therefore, establish a mature mechanism for ECDB is the foundation and core technology for electronic chart researches. The mainstream of the management of current electronic chart files system is to establish an R tree index for the main chart data files, which can provide a rapid search of required data files. The advantage of this method is flexibility. With the current conditions of limited chart data and reality of incompletion of chart data in the world, R tree indexing can highly adapt to the fact of "Load the data no matter how many they are" in a flexible way. However, with the development of informationization of navigation, more and more informationized navigational factors (including meteorological and Hydrological factors) are integrated into ECDIS. Thus, the information of single chart which ECDIS customers get will inevitably increase. To some extent, this problem will hinder the popularization and development of two important platforms for electric chart.One of the platforms is network. Web-based electronic charts were raised a. long time ago, but they have not truly be promoted and applied in practical applications. The fundamental reason for it is the speed of data transmission can not achieve the requirements for real-time nature of navigation.The other platform is an embedded platform. With its advantages such as anti-shaking, anti-rolling and low cost, embedded platform is far better than PC in the poor working environment in navigation. But the increasing of data volume... |
