1,721,567 research outputs found
Model cities
No full textThe term ?model? is now central to our thinking about how weunderstand and design cities. We suggest a variety of ways inwhich we use ?models?, linking these ideas to Abercrombie?sexposition of Town and Country Planning which represented thestate of the art fifty years ago. Here we focus on using models asphysical representations of the city, tracing the development ofsymbolic models where the focus is on simulating how functiongenerates form, to iconic models where the focus is on representingthe geometry of form in both two and three dimensions. Our questis to show how digital representation enables us to merge andmanipulate form into function and vice versa, linking traditionalarchitectural representation to patterns of land use and movement.Mathematics holds the key to simulation of many kinds andcomputers now enable us to move effortlessly from the materialworld of atoms to the ethereal world of bits and back. These newtools also provide us with powerful ways of showing how the real isable to morph into the ideal and vice versa. We argue that thisdigital world which parallels the material, now gives usunprecedented power to understand and explore cities in ways thatAbercrombie could only speculate upon, and we conclude byanticipating how we might respond to the new challenges posed byunlimited access to these virtual worlds
Distance in space syntax
No full textWe explore ways of introducing Euclidean distances associated with street systemsrepresented by axial lines into the two connectivity graphs based on points (or streetjunctions), and on lines (or streets), the so-called dual and primal representations ofthe space syntax problem. As the axial line is embedded in the connectivity graphbetween the points, for the dual problem the specification of Euclidean distancebetween points is relatively trivial but for the original syntax problem, this isproblematic in that it requires us to find a unique point representation for each line.The key is to find the centroids of the lines (of sight or unobstructed movement)between the points on each axial line, and then to use these to form a weightedcentroid of centroids. The distances between axial lines which form paths through theconnectivity graph between streets, are then computed using these centroids asstarting points for each line and routing distance through the street junctions.There are many issues involving interpretation of these measures. It might be thoughtthat the longer an axial line, the more important it is. But by giving an axial linedistance, this suggests that this is a deterrence to interaction, as in spatial interactiontheory, with longer axial lines being individually less important, notwithstanding theprobability that they are better connected within the overall street system. Clearly inmany finer-scale morphologies, this assumption might not be tenable but the measuresdeveloped here can be easily adapted to various circumstances. What this focus ondistance enables us to do is to treat a ?mixed syntax? problem where we are able toembed truly planar graphs into the axial map. This extends the technique to deal withsystems not only comprising streets down which we can see, but also fixed rail lines,subway systems, footpaths and so on which currently are hard to handle in thetraditional theory. We illustrate the extended theory for a pure syntax problem, theFrench village of Gassin, and a mixed syntax problem based on the grid of streets andunderground railways in central Melbourne. In conclusion, we introduce the notionthat proximity or adjacency at different orders might form more appropriate measuresof syntax distance, the proximity of nodes to nodes and lines to lines in the dual andthe primal being illustrated for both Gassin and central Melbourne
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Planning Support Systems: Progress, Predictions, and Speculations on the Shape of Things to Come
No full textIn this paper, we review the brief history of planning support systems, sketching the way both the fields of planning and the software that supports and informs various planning tasks have fragmented and diversified. This is due to many forces which range from changing conceptions of what planning is for and who should be involved, to the rapid dissemination of computers and their software, set against the general quest to build ever more generalized software products applicable to as many activities as possible. We identify two main drivers – the move to visualization which dominates our very interaction with the computer and the move to disseminate and share software data and ideas across the web. We attempt a brief and somewhat unsatisfactory classification of tools for PSS in terms of the planning process and the software that has evolved, but this does serve to point up the state-ofthe- art and to focus our attention on the near and medium term future. We illustrate many of these issues with three exemplars: first a land usetransportation model (LUTM) as part of a concern for climate change, second a visualization of cities in their third dimension which is driving an interest in what places look like and in London, a concern for high buildings, and finally various web-based services we are developing to share spatial data which in turn suggests ways in which stakeholders can begin to define urban issues collaboratively. All these are elements in the larger scheme of things – in the development of online collaboratories for planning support. Our review far from comprehensive and our examples are simply indicative, not definitive. We conclude with some brief suggestions for the future
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