A dynamic multi-dimensional conceptual data model for transportation applications Hande Demirel * Division of Photogrammetry, Istanbul Technical University, 34469, Maslak, Istanbul, Turkey Received 2 April 2003; accepted 26 February 2004 Available online 26 April 2004 Abstract Emerging data management needs of road administrations stress the need for data integration, when various isolated systems are updated and maintained in parallel. Since road objects can be static or dynamic, referenced to one, two, three or four dimensions, the traditional 2-D road data models are insufficient to support data integration. In order to comprehend the user requirements, a multi-dimensional conceptual data model was introduced considering a criteria list compiled based on previous studies conducted on implemented systems. The diverging approach from the traditional planar (2-D) road data models is multi- dimensionality, involving 3-D geometry and time. The presented model involves multi-dimensional location referencing, multi- scale representation, history of objects and metadata. A significant deficiency of traditional road data models, being non- integrated 1-D, 2-D and 3-D road data, was eliminated by means of the newly developed methodology, Dynamic Reference Transformation, for transformations. The designed concepts are applied to parts of real road databases using the integrated approach and results are discussed. By managing to express the user requirements in multiple dimensions, the usage of emerging spatial technologies (e.g. airborne laser scanning and digital photogrammetric cameras) in transportation applications is expected to increase. D 2004 Elsevier B.V. All rights reserved. Keywords: GIS; conceptual modeling; data model; multi-dimensional; dynamic; transportation networks; roads 1. Introduction Modeling dynamic and multi-dimensional spatial information is one of the challenging topics in current GIS research and much work has been conducted on this topic (Langran, 1993; Lee and Li, 1997; Hornsby and Egenhofer, 1997; Erwig et al., 1999; Molenaar and Cheng, 2000; Ott and Swiaczny, 2000; Peuquet, 2001; Mountrakis et al., 2002). By dynamic, we imply the ability of the system to capture the ever changing world, and by multi-dimensional the liberation of spatial data from the confines of the 2-D space of traditional maps (Lee and Molenaar, 2000). Due to the complex management tasks, the demand for dynamic and multi-dimensional GIS is increasing rapidly, espe- cially in application areas of cadastre, transportation, urban planning and environmental systems. Among these applications, the transportation sector has different demands for dynamic and multi-dimension- 0924-2716/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.isprsjprs.2004.02.002 * Tel.: +90-212-285-6110; fax: +90-212-285-6587. E-mail address: hdemirel@ins.itu.edu.tr (H. Demirel). www.elsevier.com/locate/isprsjprs ISPRS Journal of Photogrammetry & Remote Sensing 58 (2004) 301 – 314