Environment and Planning B: Urban Analytics and City Science

In the paper “Shape grammars: six types”, the issue of decidability in relation to shape grammars was introduced. Decidability concerns, first, the identification of different types of grammars, and, second, the answerability or solvability of questions about these types of grammars. The first of these two topics was explored in “Six types”. Six different types of shape grammars were defined in terms of different restrictions on rule format and rule ordering. The generative power, practicality, pedagogical value, and other characteristics of each type of shape grammars were discussed. In this paper, the second of the two topics in decidability is addressed. Five questions about the different types of shape grammars defined in “Six types” are posed. These questions are formulated for their practical value in design applications of shape grammars, as well as their theoretical interest. The answerability of each question is examined in detail for each type of shape grammar.

The incidence of change to existing houses and gardens within England's interwar residential areas is examined, the focus being on sample areas originally developed by private enterprise in Birmingham and London. Larger-scale changes, mostly subject to development control by the local authority, notably the building of additional houses within existing gardens, subdivisions and amalgamations of houses, changes of use, extensions and other significant structural works, are distinguished from changes initiated by households without planning permission, and often without building permission, such as changes to chimneys, reroofing, and changes to doors, windows, porches, and gardens. Changes subject to development control are negatively correlated, and smaller-scale changes are positively correlated, with the dwelling density at which the sample areas were originally developed. Among the factors responsible for this are the greater susceptibility of the areas of higher dwelling density to the contagious diffusion of minor and cosmetic changes.

During the past twenty years a major change has occurred in the structure, style, and content of regional planning and development in the United Kingdom, and especially in England. Whereas the pre-1979 model was dictated by central government and promoted a hierarchical ‘family of plans’, within which comprehensive regional plans were prepared in some regions, the present system has moved towards the adoption of a greater degree of partnership. Although the regional plans produced under the present system are frequently rudimentary, a foundation now exists for future development. Associated with the regional (land-use) plans are regional initiatives related to European Union Structural Funds programmes, competitiveness, transport, and housing. In moving forward to develop a more integrated and comprehensive approach to regional planning, it is important to address some of the surviving causes of the failure of regional planning in previous eras. The chief cause of failure is the absence of a settled system of regional governance and accountability.

As in other areas of planning practice, the use of GIS in neighborhood planning has assumed a technical top-down approach. Given the fact that GIS are essentially about providing and analyzing spatial data, it is difficult to envision how their use in local communities could be construed otherwise. In this paper I make a case for the need to channel intellectual energy into developing an approach and methodology for resident-generated GIS. Specifically I argue that there is a need to exploit GIS in the investigation of residents' perceptions of local neighborhood environments. I explore this approach in five sections. First, I present a definition of resident-generated GIS and position it within the larger debate on public participation GIS. Second, I offer a review of the current use of GIS in local neighborhood communities. This consists of an empirical assessment of neighborhood GIS as well as a critique of community GIS from the perspective of scholars in planning and geography. Third, I review the theoretical background that is integral to—and must form the basis of—a resident-generated GIS. Three theoretical traditions are relevant: environmental perception; indigenous information and its use in GIS; and neighborhood-level issues that could be enlightened through the use of GIS. Fourth, I propose a methodological framework for constructing and utilizing resident-generated GIS. Fifth, I discuss the political implications of a resident-generated GIS.

Low-density urbanization, also known as urban sprawl, has accelerated in the United States in recent years, In this article I will test the cumulative influence of locally adopted (municipal) land-use controls on sprawl. Land-use controls that shift the cost of development onto builders and away from the general public are found to reduce sprawl; those that mandate low densities are found cumulatively to increase sprawl, whereas urban containment systems have limited cumulative effects. Further, regions whose local governments rely on ad valorem property taxes to fund services and infrastructure tend to sprawl more than those that rely on a broader tax base.

The word vision and other related terms have become common in planning discourse. Most planning theorists, researchers, and practitioners have used them as though their meanings were self-evident and clearly agreed upon. A careful examination of ten to fifteen years of planning literature and related texts reveals not one clear meaning but as many as twenty different and distinct meanings. In this study we use some techniques of content analysis to group the various meanings of vision and visioning into two major categories, substantive and procedural. Examples of all the different uses are drawn from a variety of writing in the planning field and elsewhere. Though the use of the terms vision and visioning may not continue as they have in the past, there are two important points to this study that go beyond the words themselves. First, the concepts implied by the words remain very central to planning and therefore need to be clearly understood. Second, the approaches used in this investigation can be applied critically to the use of any popular language and terminology that enters the planning lexicon.

The existing literature on Chinese housing reform focuses on the historical account of reform events in the privatisation process. In this paper I will concentrate on the approaches and impacts of housing privatisation in China and examine the distorted and partial nature of the privatisation programme. Issues of housing price inflation, profiteering, distorted transactions, the lack of a well-developed mortgage-finance system, problems of affordability, and the continuing role of work units as mediators in the housing market are given prominent attention in this paper.

In this paper I build on current research in urban and ecological simulation modeling to develop a conceptual framework for modeling the urban ecosystem. Although important progress has been made in various areas of urban modeling, operational urban models are still primitive in terms of their ability to represent ecological processes. On the other hand, environmental models designed to assess the ecological impact of an urban region are limited in their ability to represent human systems. I present here a strategy to integrate these two lines of research into an urban ecological model (UEM). This model addresses the human dimension of the Puget Sound regional integrated simulation model (PRISM)—a multidisciplinary initiative at the University of Washington aimed at developing a dynamic and integrated understanding of the environmental and human systems in the Puget Sound. UEM simulates the environmental pressures associated with human activities under alternative demographic, economic, policy, and environmental scenarios. The specific objectives of UEM are to: quantify the major sources of human-induced environmental stresses (such as land-cover changes and nutrient discharges); determine the spatial and temporal variability of human stressors in relation to changes in the biophysical structure; relate the biophysical impacts of these stressors to the variability and spatial heterogeneity in land uses, human activities, and management practices; and predict the changes in stressors in relation to changes in human factors.