The geographical information system is viewed as a macro-system composed of a set of interlocking sub-systems. First, there is a conceptual system of ideas, which is then mapped onto a system whose components include data, hardware, and software. In the process the data are transformed into information which then becomes input for a planning system whose components include spatial and non-spatial models. This paper explicitly proposes the system concept of Forcing Functions as a key concept in G.I.S. planning, design and use. The implications of this approach for current issues such as the geo-coding alternatives, the selection of contents of a G.I.S., and the prospects for continuing viability in the context of technology transfer to developing countries, are then explored.
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