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The Research and Application of the Web Map Issuing Technology
As a product integrated with science, art and technology, web map itself has the commonness as all other media do. Flash has the advantages in the facture and the issuance of multimedia through the Internet. Combined with geographic and thematic information, we can fully exploit Flash to produce the web maps, full of interoperability, intellectuality, interest and easthetics. Using such web maps through the network, the users can enjoy the professional map service with a higher level of visualization. The following is the feasibility of issuing the web maps using the Flash technology:
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Cartographic data: Flash supports the widespread graphics of vector format such as .ai and .dxf files. We can produce the cartographic data with software which are often used as tools for map drawing such as CorelDraw, Illustrator, FreeHand, and so on. Then we can export the map data in the vector format that is acceptable by Flash. Using the powerful Flash’s capability in organizing various data, we can integrate the various cartographic data and related multimedia information and offer the users with vivid effect of visualization
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Map visualization: any technology for visualization with Flash is based on the graphic technology. The technology of Flash itself has a good foundation for graphic visualization: it pre-defines the basic graphic operation functions such as zooming in, zooming out, print and refresh, etc. Combining with the ActionScript, a programming language, lying on the background of Flash and the component which is embedded in Flash, we can realize better graphic visualization. We can also combine the Flash technology with the map elements to realize the professional functions of map display such as roaming, bird's-eye view, and the controlling of the map layers
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Interactive query about the attributive information: all of the attribute data related with the web maps can be saved in text files or in one of the relational databases. We can use the ActionScript to handle the input and output of attribute data for the web map issuing system. Thus we can satisfy the users’ needs for attribute data. The security, the management and updating of the data are also ensured
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Data updating: the data administrator of the system can update and correct the sources of the cartographic data. The sources for updating data are composed of two sides: one from the map issuer, another through the feedback from the map browsers
From the discussion above, we can say that Flash is a powerful tool for creating and issuing the maps through the Internet. Combined with other means of multimedia, it is capable to offer the users with map information quickly, interactively and satisfactorily.
The creation of the web map issuing system
The creation of the web map issuing system is composed of three parts: the designing of the user interface, the integration of cartographic data and the management of the programs. For the user interface, emphasis is put on the novel expression of the map information; for the format of the web map data, we use the vector data instead of the raster data in order to facilitate the zooming in/out functions smoothly and to alleviate the burden of data transferring; for the management of the background programs, we make full use of the script language — actionscript, which is embedded in the software — Flash MX 2004.
The design of the user interface
The user interface includes five blocks:
- The title block which introduces the whole system
- The auxiliary information block which facilitates the use of “help”, ”map legend”, “the
description of the copyright” and “feedback of the incorrect information”
- The block for cartographic data manipulation
- The block for cartographic display
- The block for query attribute data
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