This paper, the third in a series of four papers, describes a subsystem with integrative function named Geographic Intelligence (GI), from SNIRH, The National Water Resource Information System, a computational tool from the Brazilian National Water Agency (ANA), the methodological, architectural and technological aspects involved in its design and engineering – items of Software Engineering that demonstrate how to perform the technical implementation of an intelligence related to the geospatial aspects of a given computer system. Key Words: geographic services, geographic standards, GIS, implementation patterns, interoperability.