This research explores the basics of SDI, and investigates the National SDI of different countries. Further, the research analyses SDI implementation in developing country with specific reference to the National Geospatial Data Infrastructure (NGDI) of Nigeria. The research assesses the status and the milestones of NGDI implementation using key SDI components as assessment variables. These components were grouped into four classes: Policy and Legal Issues, Technical, Funding and People. A questionnaire survey via email was conducted on the stakeholders and users of geoinformation in Nigeria. From the analysis, the NGDI has an advantage of having a national policy backing its implementation and the establishment of the coordinating body. However, the lack of SDI directive and funding are major hurdles in the implementation of the NGDI making it lack behind most of the selected case study countries in other key components. Nigeria is also found to be applying a Mixed Model of NSDI implementation as both product model and process model are evident in the NGDI. In the real sense of access network and data sharing, NGDI is yet to be operational, though the project is going on.
