In this paper, we propose some adaptation to Geographical Infor-mation System (GIS) components used in GPS based navigation system. In our design process, we adopted a user-centered design approach in collaboration with final users and Orientation and Mobility (O&M) instructors. A database scheme is presented to integrate the principal classes proposed by users and O&M instructors. In addition, some analytical tools are also implemented and integrated in the GIS. This adapted GIS can improve the guidance process of existing and future EOAs. A first implementation of an adapted guidance process allowing a better representation of the surroundings is provided as an illustration of this adapted GIS. This work is part of the NAVIG system (Navigation Assisted by Artificial VIsion and GNSS), an assistive device, whose aim is to improve the Quality of Life of Visually Impaired (VI) persons via increased orientation and mobility capabilities.