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Designing a Real-Time Mobile GIS Chen Shanchun and Shi Liangping Beijing University of Post and Communication, China csc80@tom.com Wang Liang Chinese Academy of Surveying and Mapping 1. Introduction There is a famous aphorism “ time is money”, this shows the value of time in our daily life. Furthermore, about 80% of all data are somehow spatial related and most users have experiences with maps, being a simple and intuitive kind of visualization for complex spatial themes. This leads to the idea of using map-based visualizations and GIS in time critical applications (e.g. emergency management). And currently, workforce trends appear to be increasing service mobility and seizing opportunities presented by the Internet. As the Internet usage widely increases, the Internet system becomes more complicated and more difficult to deal with. This creates many network problems. In the past, most solutions were to increase resources on the web server such as hardware improvements, for example through expansion of communication bandwidth. However, these are not low-cost methods or ideal solutions. In general, the mayor concern of most web sites is the overload on servers. The system bottleneck occurs in four main areas: database, network, application server and web server. The major setback for the system bottleneck originates from the database. So optimizing the existing system such as improving the design of existing databases is an important step to enhance the overall performance. The database is an essential component in Geographic Information Systems (GIS) and without doubt, a poor design is a burden on performance. In this paper, we concentrate on the optimizing of an existing database. We propose the idea of a spatial temporal data set in wireless GIS applications that can create the Real-Time dynamic database to support the mobile application. A location-based web service is used to illustrate how it works. The objectives are to minimize the process time and to improve the data accuracy. Thus, these can provide an alternative way to enrich the work in mobile GIS applications. In addition, the assumption is made that only a simplified spatial structure will be used for the temporal dimension. The remainder of this paper is organized as follows: Section 2 gives a brief introduction to mobile GIS. Section 3 describes the spatial and related attribute data sets and the real-time dynamic database for mobile GIS. Section 4 analyses the performance of the proposed real-time dynamic database. Section 5 concludes the work. 2 Mobile GIS Mobile computing is creating fundamental changes by adding the ability to take GIS with you into the field and interact directly with the world around you. Mobile GIS is composed of a number of technologies.
Recent developments in mobile technologies have enabled GIS information to be taken into the field as digital maps on compact, powerful mobile computers, providing field access to enterprise geographic information. This enables organizations to add real-time (and near real-time) information to their enterprise database and applications, speeding up analysis, display, and decision making by using up-to-date, more accurate spatial data. 2.1 Mobile GIS Application Compare with Wireless GIS Application Mobile GIS and Wireless GIS is very similar to wire-line Web-GIS, There are three main components common to both:
There is an additional element in mobile, which is the location. 
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