Defining tread area and its spatial analysis is one of the key issues in the theory and methodology of spatial analysis in the trade/retail sector. Trade area is the space in which members of marketing chain prefer their activity. The results of such analysis are important inputs for building retail location and marketing strategy. This article tries to show the possibilities of GIS in the retail spatial analysis, emphasizing the importance of the symbiosis between traditional GIS and spatial models and methods in the defining and analysis of trade area. The focus is on the Business Analyst software package, which incorporate spatial interactive models into GIS tools. This software is used for solving great deal of spatial problems, concerning retail environment and the supply chain, with a special reference to the spatial analysis of the demand side.