It widely cited that 80% of government data is spatial in nature and the accessibility of this data is a critical aspect of E-government. Many countries are developing standardised infrastructures, which will allow sharing and reuse of spatial data. This paper presents the findings of a national level case study of the Spatial Data Infrastructure implementation in Ireland. The study draws on concepts from Corporate Information Infrastructure (CII), most notably the power of the installed base, role of standardisation, multiple actors and top-down versus bottom-up tensions. A significant outcome of this paper is the application of the CII concepts to a national level case study.