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Study of Landuse – Groundwater relationship using an Integrated Remote Sensing and GIS appraoch
5. Weighted Index Overlay Model for Groundwater Prospects Weighted overlay analysis is a simple and straightforward method for a combined analysis of multi-class maps. The efficacy of this method lies in that human judgement can be incorporated in the analysis. A weight represents the relative importance of a parameter vis-a-vis the objective. Weighted index overlay method takes into consideration the relative importance of the parameters and the classes belonging to each parameter. There is no standard scale for a simple weighted overlay method. For this purpose, criteria for the analysis should be defined and each parameter should be assigned importance (Saraf and Choudhury, 1997 and Saraf and Choudhury, 1998). Determination of weightage of each class is the most crucial in integrated analysis, as the output is largely dependent on the assignment of appropriate weightage. Consideration of relative importance leads to a better representation of the actual ground situation (Choudhury, 1999). Considering the hydro-geomorphic conditions of the area weighted indexing has been adopted (Table 2) to delineate groundwater prospective zones (Figure 3) considering five parameters namely geology, geomorphology, soils, slope and lineaments.  Figure 3 Groundwater prospective zones analysed on the basis of geological, geomorphological, soils, lineaments and slope information and their analysis using GIS
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