M4WebGIS: A Mobile Agent-based Middleware for WebGIS

摘要

Geographic Information Systems (GIS) are now widely used. WebGIS, pushed by keeping increasing information resources, enriches functions and content of GIS under WWW framework. We propose a mobile agent-based middleware for WebGIS, called M4WebGIS, which consists of a group of coordinated agents for users to retrieve geographic information. Function logic of server part, processing logic of client part and underlying operation of system, such as interaction with operating system, network, and database, are designed separately in M4WebGIS to achieve stability. Independence between modules ensures extensibility. Moreover, functions such as map management, user management and data management, make M4WebGIS as an integrated middleware system. M4WebGIS offers functions, such as roaming and zooming in several map layers, spatial information analysis and retrieval, database supporting, real-time event tracking, different systems compatibility supporting, and adding spatial characteristics to website. Using M4WebGIS, application developers, data distributors and spatial database engine vendors can add dynamic, data-driven map to their applications. M4WebGIS can be integrated into development environment seamlessly, reducing application system complexity, speeding up development progress of applications, alleviating cost and enhancing maintainability as well. In the distributed environment, M4WebGIS achieves pretty parallel computing, balances network workload, acquires exact geographic information and saves network bandwidth.