Scientific Research and Essays Vol. 6(4), pp. 993-1000, 18 February, 2011 Available online at http://www.academicjournals.org/SRE DOI: 10.5897/SRE10.416 ISSN 1992-2248 ©2011 Academic Journals Full Length Research Paper An ontology-based visualization for mobile geoinformation services Ozgun Akcay* and Orhan Altan Division of Photogrammetry, Faculty of Civil Engineering, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey. Accepted 11 August, 2010 In mobile geoinformation services, most intelligent systems ignore the users’ states and roles and only include the user's location. However, different user profiles need customized visualization styles in order to provide relevant spatial data. With the availability of a variety of data sources and the ability for continuous data updates, the service is able to perceive and react to instant changes. The aim of this research is to describe contextual ontological model which provides visualization on mobile devices. Therefore, intelligent visualization explained in this study is defined by a complete semantic model of the Ontology Web Language – Description Logic (OWL-DL) and Semantic Web Rule Language (SWRL). Consequently, a mobile visualization service sensitive to the instant changes of the user’s situation has been proposed. Egocentric design of a map-based service has been tested on a scenario-based application of a mobile emulator. Key words: Context, ontology, knowledge-base, mobile, reasoning, visualization. INTRODUCTION New technologies such as wireless communications, advanced sensors and high speed processors have changed approaches to many applications and techniques in various engineering fields. Clearly, distributed GIS has also been affected by these new developments. Technological developments have significantly increased the usage of these services in daily life. Mobile GIS systems therefore need to be adapted to its environment, the elements of which can be defined by context modelling. Context modelling is a simplified representation of the real world to enable management of the information in the computer environment. Visualization on mobile devices is considered in a context model that also includes notions of relevance. The proposed system is able to adapt to the changing situations in order to create a relevant visual design of the spatial data on small mobile devices. If a visual parameter is accepted as an actuality in the conceptualization of the context model, relations can be *Corresponding author. E-mail: akcayoz@itu.edu.tr. Tel: +90- 212-285-6562. Fax: +90-212-285-6587. established between the real world and the visualization of the spatial data. This research attempts to integrate general principles for the mobile context and the newly determined visualization parameters for the context of mobile devices, to obtain a system that is sensitive to principles of relevance. Researchers have presented different points of views on relevance theories in support of new context models that are able to provide relevant data to the user. The theories need to be reviewed, though context-aware applications inherently provide relevance by themselves. According to Saracevic (1996), manifestations of relevance are based on relations between components of relevance and texts. Text in this context represents all relevant information about object types such as documents, images and sounds. Therefore, every manifestation of relevance includes relations with objects. Saracevic (1996) described five manifestations of relevance: Algorithmic, topical, cognitive, situational and motivational relevance. Relevance also becomes a key notion in GIS research when retrieving appropriate spatial information for different applications, such as from databases and for visualization. Specifically, visualization issues have been focused on in this study. Edwardes et al. (2005) proposed