Although a large number of multiattribute decision analysis (MADA) methods is available (Hwang and Yoon 1981), the theoretical and applied research about GIS-MADA has focused on a relatively small number of multiattribute procedures including: the weighted linear combination, ideal point methods, the analytic hierarchy process/analytic network process, and outranking methods (see Sect. 3.3.2). These four methods are discussed in this Chapter. We introduce the conventional MADA methods and discuss their extensions to the spatially explicit models (see Sect. 1.4). The chapter also provides a brief overview of GIS-based applications for each of the four methods.