Prasanna Divigalpitiya准教授Prasanna Divigalpitiya
博士： 都市共生デザイン 持続都市建築システム国際
Modern cities are far more complex than we generally assume. This is especially true for rapidly growing South and South Eastern Asian cities. The outward expansion of settlements in those cities follows organic growth pattern. While outward growth is more prominent, there are other attributes of urban growth. The rapid growth process also modifies the organization of the city activities itself in the form of shifting activity centers, changing urban densities and changing accessibility conditions. My early research focused on measuring spatial and temporal dynamics of rapidly growing cities and building models to forecast future urban form based on that knowledge. Many countries in Asia are promoting decentralization of urban governance. Decentralization and liberalization of the economy have its impact on urban growth in the form of land supply and resulting growth patterns. Scattered new urban centers in large urban agglomerations that appearing in South Asian and South East Asian cities are a visible clue to this changing growth patterns. My recent research attempts to measure these changes quantitatively.
Most profound change in urban planning research during the last half a century has been our ability to use the computer as a digital laboratory for controlled experimentation. Computer has increased our ability to utilize large amount of data and develop models that can simulate complex urbanization patterns and future scenarios. I have developed dynamic computer models that can simulate urban growth patterns to understand future urban scenarios. The purpose of such modeling was not producing accurate description of the future. The purpose was to develop the essential structure of the city to uncover the basic mechanism of urbanization. Developing new techniques to measure urban changes quantitatively is an important first step in modeling. I have used multiple methods borrowed from diverse fields such as information sciences and landscape ecology to derive data for my models.
South and South Asian cities are moving from centralized technocratic approach of urban planning and governance to decentralized multi-stockholder approach recently. My current research tries to understand how this new operational structure will change future urban growth patterns. The urban growth process of several South and Southeast Asian cities selected based on economic development and planning practice was studied in this research. Characteristics of urbanization such as fragmentation, activity spaces, decentralization, density and urban growth were measured using land use and demographic data. Series of matrices and geospatial calculations was used for the calculation. This information will be used to analyze the spatial and temporal dynamics of urban expansion and its relationship to planning practice.
Several proprietary, open source and own custom-built software tools were used for the research at different stages. Image processing software such as IDRISI and ERDAS IMAGINE was used to develop land cover data sets from satellite images. Socio economic and urban planning data were prepared using ArcGIS tools. It is often convenient to have all data as a time series data set in a GIS database for analysis. I have used both proprietary and open source GIS tools for that purpose. Urban growth simulation models are software tools that calculate urban growth iteratively using a set of rules derived from historic growth patterns. I have written my own software for urban growth models. Developing languages such as C, C++ and Python were used for software development depending on the complexity of the calculation. In my current research, data preparation and most of the geospatial calculations were carried out using ArcGIS tools and customized Python scripts.
Planning is a problem-solving approach that is concerned with the forces that influence the quality of life in neighborhoods and cities. Therefore, most important aspect of research in planning is identifying urban issues. Urban planning is the society’s means for addressing those numerous problems in a creative, positive manner. Therefore, urban planning research must ultimately point to planning solutions.
When we consider the proportion of world population living in urban areas, urban planning has become one of the most important occupations. Postgraduate students in urban planning must develop critical thinking in order to succeed in future urban planning responsibilities.
Urban planning involves integrating the work of multiple disciplines in to a coherent plan for the whole city or for a region. Planners involve any kind of activates that influence the future of neighborhoods, cities and the region. Collaboration between multiple disciplines is essential for creative and adoptive urban planning solutions.
Changing suburban areas in Japanese and Western cities to understand how cities are adopting to the demographic changes.
1. UNHABITAT (2010) The State of Asian Cities 2010/11, UNHABITAT.
2. Alexander, E. R. (2006). Evaluation in planning: evolution and prospects. Aldershot, England; Ashgate Pub.