Planning in the Limelight of an Unpredictable Future

In accordance with the line of thought of Scholl (2005), we create urban planning strategies which act as guidelines into the future. Obviously, imagined futures are helpful in debating the decisions and choices to be made. However, imagining futures by extrapolating facts from the past and the here and now does have is limited. Thinking along linear Newtonian cause-effect lines seems dubious from the perspective of a world considered to be in continuous change. The Newtonian worldview has been favoured in spatial planning for a long time. This technical paradigm addresses the idea of a factual reality, a certainty within the reach and a linear route into the future. Apart from a factual reality, an agreed reality is also considered to respond to the built environment. However, we have to be aware that the only constant factor is probably discontinuous change. Kropf (2001) notes that urban form and the social and economic life of cities are best apprehended by descriptions of inter-alia transformation, cycles, growth and decay, catastrophes,shifting centres of activity, dynamics and influence

: FRACTALOPOLIS MODEL - ACCESSIBILITY, EVALUATION & MORPHOLOGICAL RULES

page number: 74A sustainable and sustaining planning strategy is globally important for metropolitan areas. Sustainable planning addresses the development of strategies to reduce the use of resources, increase economic efficiency and improve integration of social aspects. In contrast, splinter development (e.g. urban sprawl) involves damage to nature and generation of an increasing volume of traffic (these are the main criticisms following a study by Newman and Kenworthy (1989) on the relationship between settlement density and energy consumption). Interestingly, the overly compact city also has this effect as it may generate traffic flows for accessing green and leisure areas, or changes of residence due to a favouring of sites that lie farther away from the centre than the inhabitants' current places of residence. Households not only consume urban amenities integrated into densely populated areas, but also aspire to have access to green and leisure areas. Schwanen et al. (2004) showed that households usually optimize their residential choice with respect to accessibility to various types of amenities, which is inherently linked to the frequentation rate of these amenities (daily, weekly, monthly, and occasional) (c.f. spatial practice of people). Moreover, on an urban scale, over-compactness causes ecological problems such as a lack of green wedges for supplying the city with fresh air (urban microclimate). Thus, we aim to find a solution for managing dispersed development which marries the twin elements of green and built-up space in a highly efficient manner. This solution also needs to incorporate dynamic aspects of a city as well as minimizing traffic costs and emissions. Based on the observation that urban space is founded on the principle of fractal geometry, it seems interesting to explore to what extent fractal geometry may be drawn upon for solving the spatial antagonism of compactness and urban sprawl.Une stratégie d'aménagement durable représente un enjeu important pour le développement des agglomérations contemporaines. L'aménagement durable implique le développement de stratégies visant à réduire l'utilisation des ressources, accroître l'efficacité économique et améliorer l'intégration des aspects sociaux (ex. environnements conviviaux pour les piétons, équilibre entre modes de transport public/privé, réseaux routiers performants, viabilisation des terres agricoles, économie du mouvement ; accès à l'emploi pour tous, commerces, services ; santé, culture et loisirs). A l'inverse, le développement fractal (ex. étalement urbain) n'est pas sans répercussions néfastes sur la nature et tend à augmenter le volume du trafic (principales critiques émises dans une étude de Newman & Kenworthy, 1989, portant sur les relations entre densité d'implantation et consommation d'énergie). Fait intéressant, une ville trop compacte induit un effet semblable car elle peut être à l'origine de flux de trafic pour accéder aux espaces verts et récréatifs ou des déménagements vers des endroits plus éloignés du centre que les lieux de résidence actuels des citadins. Les ménages ne se contentent pas d'utiliser les aménagements urbains intégrés dans les zones à forte densité de population, ils aspirent également à un accès aux espaces verts et récréatifs. Schwanen et al. (2004) ont mis en évidence le fait que les ménages tendaient à optimiser leur choix de résidence en fonction de l'accessibilité de divers types de commodités, un phénomène foncièrement lié au taux de fréquentation (quotidienne, hebdomadaire, mensuelle et occasionnelle) de ces dernières (cf. pratiques spatiales de la population). A l'échelle urbaine, une compacité excessive entraîne par ailleurs des problèmes écologiques, tels que le manque d'espaces verts pour approvisionner la ville en air frais (microclimat urbain). Nous recherchons ainsi une solution afin de gérer le développement fractal de manière à pouvoir concilier efficacement le couple antinomique espaces verts/espaces urbanisés. Cette solution doit également intégrer les aspects dynamiques d'une ville et minimiser les émissions et les coûts du trafic et prévenir la désagrégation des terres agricoles. Sur la base de l'observation selon laquelle l'espace urbain repose sur le principe de la géométrie fractale, il paraît intéressant d'explorer dans quelle mesure la géométrie fractale peut être mise à contribution en vue de résoudre l'antagonisme spatial compacité/étalement urbain

Exploring Challenges in Space Syntax Theory Building:The Use of Positivist and Hermeneutic Explanatory Models

The planning and building of sustainable cities and communities yields operational theories on urban space. The novelty of this paper is that it discusses and explores the challenges for space syntax theory building within two key research traditions: positivism and hermeneutics. Applying a theory of science perspective, we first discuss the explanatory power of space syntax and its applications. Next, we distinguish between theories that attempt to explain a phenomenon and theories that seek to understand it, based on Von Wright's modal logics and Bhaskar's critical realism models. We demonstrate that space syntax research that focuses on spatial configurative changes in built environments, movement and economic activities can explain changes in a built environment in terms of cause and effect (positivism), whereas historical research or research focusing on social rationality, space and crime or cognition seeks to develop an understanding of the inherent cultural meaning of the space under investigation (hermeneutics). Evidently, the effect of human intentions and behaviour on spatial structures depends on the type of rationality underlying these intentions, which is the focus of this study. Positivist explanatory models are appropriate for examining market rationality in cases that entail unambiguous intentionality and that are associated with a high degree of predictability. By contrast, other kinds of reasoning require a hermeneutic understanding.</p