1 Development of a prototype for Spatial Decision Support System in risk reduction based on open-source web-based platform Roya Olyazadeh, Zar Chi Aye, Michel Jaboyedoff Centre de recherches en environnement terrestre (CRET), Faculté des géosciences et de l'environnement, Université de Lausanne.1015 Lausanne, Suisse Roya.Olyazadeh@unil.ch; Zarchi.Aye@unil.ch; Michel.Jaboyedoff@unil.ch Abstract: This paper presents the development of a prototype for a Spatial Decision Support System (SDSS) in risk reduction based on available open-source geo-web platforms. The main purpose of this system is to find a way to make SDSS more practical and user-friendly, thereby reducing the cost of and time required by the project. Malczewski 1999 [1] describes SDSS as an interactive computer-based system designed to use spatial information to support a decision maker with a final solution based on the semi-structured spatial problems. A SDSS is usually composed of users, decisions (also known as “alternatives”) and criteria (or “indicators”) which represent the costs and benefits of each alternative. We will begin by demonstrating the modularity of SDSS platform for risk reduction. SDSS consists of different components or modules. In this specific research, the modules are Input module, Risk module, Visualization module (which uses GIS tools) and Decision Module. Each of these modules is equipped with different functionality and analytical process and will be used by different organizations such as spatial planner, geologies, engineering for risk reduction mitigation, local authorities, etc. This means that the whole SDSS can benefit from a collaboration platform between all organizations, stakeholders and their responsibilities that are involved in decision making and risk reduction. In addition, the system is planned to apply Multi Criteria Decision Making (MCDM) to evaluate the most appropriate alternative options in Decision Module. This work is a part of the ongoing 7th Framework Program “CHANGES” (2011-2014, Grant Agreement No. 263953) of the European Commission. Keywords: SDSS, MCDM, Open source, Web-based, Risk management 1. Introduction Nowadays automation and web-based decision support systems become more practical with development and capabilities of World-Wide-Web, distributed computing and computer human interaction. Decision support system (DSS) proposed by Simon [2] in mid-1960s. The major application of DSS is accessing and analyzing of database for supporting single or group decision making. Power [3] summarized DSS to progresses of model-driven, data-driven, communications-driven, document-driven and knowledge-driven DSS. Data Base Management System (DBMS) can store and manipulate spatial data, query and analytical modeling while a Model Base Management system (MBMS) performs a task which is analogue to the function of DBMS and instead of storing data, storing the element of elements of models. Our SDSS contains both DBMS and MBMS. Beginning in about 1980, development of Spatial Decision support System (SDSS) in parallel with Multi Criteria Decision Making (MCDM) is introduced by Malczewski [1]. Today SDSS uses in different disciplines and various applications such as spatial planning, risk management and etc. Furthermore application in the field of Planning Support System (PSS) is offered by Geertman and Stillwell [4, 5]. Basically a SDSS has the following components as shown in Figure1: Geographic Data Base, Model Base, Dialog Generation management which is related to visualization, communication between users and the rest of system as well as user-friendliness [6].