| The electric map is a new type of map came into being with the using of the technology of Computer in the map graphics realm. It can be thought as a visualization map, which can be displayed in the desktop computer or the computer with tangible screen. The electric map is very popular for its advantage, such as shareability, movability, flexibility. The multi-media electric map is extended from the electric map. It includes various medium such as text, sketch, chart, picture, voice, cartoon and video etc. The computer, GIS, multimedia and other new related technology have a great effect on the development of the multi-media electric map. In addition to the advantage of the electric map, it increases a method to display map's spatial information with multi-media, releasing the spatial information fair, vividly in hearing, vision etc.The electric map has a very important connection with geography information system. It is kept touch with customers by the geography information system and is also the carrier of the geography information system's data. It is to say, the electric map is a part of the geography information system;the geography information system is a super structure of the electric map. The development mode of the geography information system mainly has three kinds of modes: stand-alone development, autoecious development and Component GIS development. Because Component GIS have the advantage both of the GIS software and other visual software for program. Currently, Component GIS has become the most important GIS development mode, and it is also the first choice of the author to study the multi-media electric map.At present, the main component GIS are MapObjects developed by the ESRI company and MapX by the Maplnfo company. Because MapObjects is easier to use than MapX, the author finally chose MapObjects and VB to develop the information release function of the multi-media electric map.Multimedia technology treats audio, text and image across-the-boardwith calculator, it brings calculator to transinformation from simple text mode till figure, image, sound and video and takes computer to high-tech desktop system with enjoyment, adventure and alternating study from rebarbative mainframe terminal. Its application makes the map information have essentiality variance in phraseology and transmission efficiency. Therewithal the visualization of map information comes into a spick-and-span time.The multi-media electric map has three mainly objects to operates, including the space data, the attribute data and multi-media data as well, the spatial data describes the geographical phenomenon or the LOCA, shape, size and their relation of the geographic entity;the attribute data describes qualitative or ration indices of the geographical phenomenon or geographic entity, such as statistical data etc. It has two ways to got multi-media data. One way is to digitize the multi-media data and put it into the database before playing, to fetch it from the database while broadcast;another way is, to release the visible result of spatial analysis and statistical analysis when the multi-media electric map is being used.The data's organization and management are the foundations of the multi-media electric map to release its information, and to establish the database is the most important thing. The space data can be organized and managed by subarea, delamination and object-oriented. Both the attribute data and the multi-media data can be managed with relational database. Especially, because the multi-media data includes multiform data and its format can't be unitized, it's too complex to store and manage.The spatial data and the attribute data are managed with a hybrid database, in which the shape file is the leading part. Shape file is suitable for the data of middle or pony map, and mass data would be managed with private database in common, which is joined with ArcSDE. Of course, it is elastic to program with MapObjects. When transforming data from shape file to large database, we just need to modify several lines of codes for opening the data source and then almost all the codes can be converted to use in the large database. Using an example, the author introduced the course of establishing a hybrid database with shape file in detail. Currently, there are several kinds of multi-media database in common use, such as object-oriented multimedia database, hypermedia multimedia database and prolate relational database etc.Based on the characteristics of these databases, the author chose the commercial database management system to manage the multi-media data. Therewith. Using an example, the author introduced the course of designing and establishing the multi-media database in detail.In the chapter 4, the author studied the theory of Shortest Path Algorithm and buffer analyses of the multi-media electric map, beginning from the method to get dynamic multi-media information. With theoretical investigation, the author realized partial function of the multi-media electric map, such as map display, spatial analysis and query, multimedia information display etc. Then in the chapter 5, the author introduced them in detail. Finally, the author summarized the research, and indicated what should be done for the research of the multi-media electric map in the future.
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