This paper is the last one in a series of four papers and presents a minimal geographic services’ specification, based in the core related to business requirements, specially spatial and non-spatial associations, a specification that will serve as an implementation guidance for a functional geographic solution based on a Service-Oriented Architecture (SOA), named Geographic Intelligence (GI), a computational GIS tool developed by the Brazilian National Water Agency (ANA). Key Words: geospatial services, GIS, SOA.