For such a daunting task, I need a high-level conceptual ladder to enable me to obtain a birds-eye view of this field. The ladder I stand on for this paper is essentially a linguistic metaphor borrowed from Casti (1994, 1997). According to Casti (1994; 1997), the essence of any analysis or modeling is a two-way mapping process: to encode certain characterizations (observable) in a natural (real world) system (N) into symbols and strings (theorems) in a formal (either logical or mathematical) system (F), and then to decode the modeling results from the formal system into words meaningful to the observable in the real world system. Casti further argues that the key to understanding this process of formalization is to recognize that all notions of meaning (semantics) reside in the real world system N. In contrast, F consists of mere abstract symbols and the rules (syntax) for how these symbols can be manipulated to form new strings. The meaning of these symbols are extracted by decoding the strings back into N. The semantics of N is often rendered in induction and causation whereas the syntax of system F favors deduction and inferences. The goal of any analysis or modeling exercises is to first find the most essential characterizations of system N, and search for the most truthful representation of these characterizations in system F. Analysis or modeling is not successful if we fail to interpret the meaning of system F in the context of system N.
By applying Casti’s framework to the field of GIS-based spatial analysis and modeling, I have the following observations I would like to discuss with my colleagues during the workshop: First, I believe that, in general, the efforts of trying to make GIS a robust spatial analytical tool have been less successful. The generic, syntax-driven analytical procedures, as reviewed in Bailey (1994), are still confined to academics. Neither GIS vendors nor most GIS users have developed a keen interest in those sophisticated procedures. Instead, the recent development of GIS technology seems to reflect the growing emphasis on the entire life-cycle of geographic information from data capture to storage to retrieval to visualization. To most GIS users, analysis seems to fade away as the defining GIS function. Part of the reason for this situation is caused by the fact that most GIS users (except for academic researchers) and commercial GIS software developers have a very difficult time to comprehend the semantics of these statistical procedures. Second, instead of embedding generic, syntax-driven statistic procedures in GIS, the past several years have witnessed the development of specific, semantics-based modeling procedures either as part of a commercial GIS package or as a stand-alone package capable of linking to GIS via data exchange (Wilson, 1996). These modeling procedures are generally tied to a very specific domain that has a set of commonly accepted models in practice. Products such as RiverCAD, HEC-RAS, TransCAD, and TransPlan etc. are some of the examples of this trend. The market demands for these specific modeling functions /packages (not the generic spatial statistic procedures) seem to continue to grow, but the development of these specific modeling tool boxes is most likely to be in the hands of GIS users and researchers, either using the built-in GIS script languages such as Avenue or MapBasic or other high-level languages such as VisualBasic, C++ etc. Current efforts toward the interoperable GIS will greatly facilitate the implementation of various models in the GIS context. The main role of GIS is essentially to provide modelers a consistent digital representation for them to implement their specific models. Third, as for the future of GIS-based spatial analysis and modeling, this paper favors a semantics-driven approach with emphasis on contextual meanings. Instead of looking for generic, spatial statistic procedures detached from specific contexts, this semantics-driven approach will serve us well not only in practice (to meet the growing demands of socio-economic and environmental modeling using GIS) but also in research. The semantics-driven approach will inevitably lead us to address questions raised at both ontological and epistemological levels. By shifting from a syntax-driven to a semantics-driven approach, we can better address those critics of GIS from social theorists as well as scientists from specific disciplines. Our answers to these ontological and epistemological questions will determine, to a large extent, what kind of spatial analysis and modeling practice we will conduct tomorrow.
I will have a more polished paper written before the workshop and it will be circulated among the participants during the workshop.
Casti, J L, 1994 Complexification: Explaining a paradoxical world through the science of surprise (New York: HarperCollins).
Casti, J L, 1997 Would-Be Worlds: How simulation is changing the frontiers of science (New York: John Wiley & Sons Inc.)
Wilson, 1996. GIS-Based Land Surface/Subsurface Modeling: New Potential for New Models? Proceedings of the Third International Workshop on Environmental Modeling. http://www.ncgia.ucsb.edu/conf/SANTA_FE_CD- ROM/sf_papers/wilson_john/wilson.html
Master of Science, 09/86--06/89
Institute of Remote Sensing
Peking University
Beijing 100871, P.R. China
Bachelor of Science, 09/82--06/86
(with high honors)
Department of Geography
Peking University
Beijing 100871, P.R. China
Doctoral Dissertation: GIS-Based Spatial Analysis, Modeling, and Simulation: A Case Study in the Changing Urban Spatial Structure of Hong Kong, 1966-2006. Date Completed: June 12, 1993.
Senior Faculty Fellow, 01/15/1995 - present, Hazard Reduction and Recovery
Center (HRRC),
Texas A&M University, Texas 77843.
Assistant Professor, 09/01/1993 --05/15/97, Department of Geography,
Texas A&M University, College Station, Texas 77843.
Graduate Teaching Assistant, 09/14/1989-06/12/1993, Department of Geography,
The University of Georgia, Athens, GA 30602.
Research Assistant (part time), 10/01/1992-07/15/1993, Small Business Development Center (SBDC), The University of Georgia.
Sui, D.Z., 1998. Deconstructing virtual cities: From unreality to hyperreality. Urban Geography (accepted, in press)
Sui, D. Z., 1998, GIS, environmental equity, and the modifiable areal unit problem. Book chapter for Advances in GIS -- Bridging the Atlantic. London, Taylor & Francis (accepted, in press).
Sui, D.Z., 1997. Reconstructing urban reality: From GIS to electropolis. Urban Geography, Vol. 18, No.1, pp.74-89.
Sui, D.Z., 1997, The syntax and semantics of urban modeling: Versions vs. visions. In The State-of-the-Art of Land Use Modeling. National Center for Geographic Information and Analysis (NCGIA), Santa Barbara, CA.
Sui, D. Z., 1996. Urban forms, urban processes, and urban policies: A research agenda for the metropolis in the 21st century" In Spatial Technologies, Geographic Information, and the City, compiled by H. Couclelis (Santa Barbara, CA.: NCGIA Technical Report 96- 10), 210-213.
Sui, D.Z., 1995, Modeling the spatial economic impacts of new town development in Hong Kong: A GIS-Based shift-share analysis. Socio-Economic Planning Science. Vol.29, No.3, pp.227-243.
Sui, D.Z. and C.P. Lo, 1995, Prediction of Hong Kong’s future economic and spatial development using GIS simulation. Environment and Development. Vol. 5, No.3, pp.103-124.
Sui, D.Z., 1994, GIS and urban studies: Positivism, post-positivism, and beyond. Urban Geography. Vol. 14, No.3, pp.258-278.
Best Ph.D. Student Paper Award, awarded by Southeast Division of Association of American Geographers (SEDAAG),1992.
$ 499,500, "Understanding Criticalities in Urban Metabolism: Toward a new paradigm in urban sustainable development," with Robert Harriss, Jonathan Phillips, and Arthur Sullivan, submitted to NSF's Urban Research Initiative (URI) (pending).
$ 79,000, "Exploring the Environmental Impacts of the E-merging Digital Economy: Towards an informational ecology for the greening of electronic commerce," submitted to EPA's STAR program (pending).