Geographical Information Systems (GIS) are proving difficult to both define and effectively implement in Victorian Local Government. Current innovation diffusion theory, and emerging GIS and IS implementation theory are used to develop a framework for the implementation of either a new GIS, or for improving a currently ineffective GIS. The thesis describes a method of practically redefining GIS in the Local Government environment and then applying diffusion principles during the implementation of GIS. The first area of new investigation in the thesis is the approach to defining the GIS requirements of Local Government. In this thesis, GIS in Local Government is defined by starting with the business requirements and then letting them define the high level technical and functional requirements. This obtains a different answer from the traditional approach of assuming that current generic high level technical and functional definitions of GIS are correct, and that implementation is a selection and fine tuning process. The new approach is based mainly on the “productional perspective”; developed in recent theoretical GIS diffusion studies. The major difference is that GIS implementation in Local Government does not necessarily include the requirement for the design and construction of a specific GIS database. The GIS simply consists of graphical maps that spatially index and read existing non spatial databases within the Local Government IS environment. (For complete abstract open document)