A spatial data infrastructure (SDI), also called geospatial data infrastructure,[1] is a data infrastructure implementing a framework of geographic data, metadata, users and tools that are interactively connected in order to use spatial data in an efficient and flexible way. Another definition is "the technology, policies, standards, human resources, and related activities necessary to acquire, process, distribute, use, maintain, and preserve spatial data".[2] Most commonly, institutions with large repositories of geographic data (especially government agencies) create SDIs to facilitate the sharing of their data with a broader audience.
A further definition is given in Kuhn (2005):[3] "An SDI is a coordinated series of agreements on technology standards, institutional arrangements, and policies that enable the discovery and use of geospatial information by users and for purposes other than those it was created for."