Design And Development Of Management Information System For Liaohe Estuary Wetland Based On WebGIS

Wetland is a unique ecosystem with high ecological, economic and social value. It not only provides plenty of food, material and water for human, but also plays an irreplaceable role in ecological balance, biodiversity and rare species, water conservation, refraining flood and drought, pollution degradation, climate regulation, groundwater recharge, and so on. Liaohe estuary wetland is a typical one of north China's wetlands, and it is also the focus area of Liaohe water pollution project. Due to natural and man-made reasons, this wetland becomes a fragile ecosystem while its purification function declines, all kinds of resources are damaged, industrial pollution becomes more and more serious. It is an urgent mission to protect the wetland's existing resources and restore its ecological functions like pollution purification. The main research objective of this article is to build management information system for Liaohe estuary wetland integrated with original data and existing research, so as to provide support for wetland restoration, scientific management and to suggest an exemplary program for north China's wetlands.This article analyzes domestic and international status in wetland management information system and then selects WebGIS technology to design and develop management information system for Liaohe estuary wetland. First, it intensively studies theories related to WebGIS about its characteristic, basic framework, architecture and implementation technology; Second, in contrast to other programs, this article uses the classic B/S architecture and mixed-mode implementation technologies in both server side and client side; Finally, the system is achieved with open-source software framework, ka-Map+Apache+MapServer+PostgreSQL/ PostGIS+FreeBSD, ka-Map as client-side platform, Apache and MapServer as web server and GIS application server respectively, PostgreSQL database and its spatial extension PostGIS for data management, while FreeBSD is used for server-side operating system.Combined with wetland data's characteristic, this paper details the advantages and disadvantages of different schemes for storing spatial data. On basis of that, the object-relational database management system is selected to achieve the Liaohe estuary wetland database. In accordance with actual demand of the system database, this article studies on data organization, data object classes, table structure and so on, succeeding in storing both spatial data and attribute data through PostgreSQL/PostGIS after completing the database's logical design and physical design. According to the design program, the system functional requirements are mainly divided into four parts—user management, data management, GIS basic functions and wetland-specific analysis module. With enough work, this article has constructed the developing platform for the system and achieved in general GIS functions.During the process of system development, many excellent features have been guaranteed through comprehensive consideration of all kinds of factors. By using object-relational database management system, data management is ensured to be accurate, real-time, secure and uniform; with ka-Map client based on Ajax technology, good user experience is enhanced and the server-side burden is lightened; all software is open source to reduce development costs and ensure the system's rapid updates and upgrades.