Applying Depth Decay Functions to Space Syntax Network Graphs

12-15 June 200

A spatial signature of sprawl: or the proportion and distribution of linear networkcircuits

This paper sets out to investigate whether the frequency distribution ofthe linear network circuits within a graph-based representation of aroad transportation system can be helpful in identifying sprawl and, inparticular, whether a 'spatial signature of sprawl' can be determined.This paper is based upon an earlier study on Peachtree City, Georgia and in particular of its dual transportation system (roads and golf cartpaths). In order to fully understand the effect that the dualtransportation system has upon Peachtree City, the frequencydistribution of its circuits are compared to three, supposed, 'suburban' areas and three, supposed, 'urban' districts. The conclusion of thispaper is that there is, unquestionably, a measurable continuum between 'suburbia' and 'urbanity' and that this is reflected in the frequency,length and distribution of the graph network circuits. The main sectionof this paper is concerned with the presentation and discussion ofalternative algorithms for calculating these circuits. This section isfollowed by an introduction of a selection of methods for interpretingthe resultant data. Finally, with respect to Peachtree City, this paperconcludes that the effect of the dual transportation system is to make it more 'urban' than it would otherwise be, although it remains adistinctly suburban environment

OmniVista:an application for isovist field and path analysis

This paper briefly describes the software application OmniVista written for the Apple MacintoshPlatform. OmniVista is essentially an isovist generating application, which uses the 2d planof a building or urban environment as input data, and then can be used in one of threemodal ways. Firstly, point isovists can be generated by ?clicking? onto any location in theenvironment. Secondly, all navigable space can be flood-filled with points, which may then beused to generate a field of isovists. Finally, a path of points can be used to examine howisovist properties vary along the path - the results of this can either be output as numericaldata, or exported as a series of pictures, which may be combined to form an animation of thevarying isovists along the route. This paper will examine all three modes of use in turn,starting from the simplest (point) to the more complex (the path). A description and equationfor all isovist measures used in the application will also be given as an appendix to thepaper

An American prototopia: or Peachtree City as an inadvertent, sustainable solution to urban sprawl

Peachtree City is a city with a secondary transportation network, known as the path system. This paperseeks to determine why the path system is so successful and whether there are fundamental spatial,configurational properties which underpin its achievement. This paper examines the axial-line network ofpaths as a distinct network then as part of the larger, combined system of both paths and roads.The finding of this paper is that the cart path system, although unintelligible in its own right, serves thepurpose of reducing the overall number of cul-de-sacs in the city whilst increasing its axial ringiness. Anew measure for calculating the spatial signature of sprawl is suggested - the proportion and distribution ofcircuit lengths in the axial map. The paper continues by discussing the social, economic and environmentalbenefits of the path system, with the proviso that these benefits arise only from a successful system and thata partial factor contributing to this must be the spatial regularities revealed in the axial analyses. It concludsby suggesting that without the cart path system, Peachtree City would consist of nothing more thanaggregations of typical suburban developments with one or two primary road-entrances accessed fromarterial-roads and containing a high ratio of cul-de-sacs.This paper concludes by suggesting how Peachtree City could be held to be the blue-print of a ?protopia?,presenting a principle by which American suburbia could be transformed into sustainable communities andyet do so in a manner which would be distinctly American in character and hence palatable to its residentsunlike many current, public-transport focused proposals

OmniVista:an application for isovist field and path analysis

This paper briefly describes the software application OmniVista written for the Apple MacintoshPlatform. OmniVista is essentially an isovist generating application, which uses the 2d planof a building or urban environment as input data, and then can be used in one of threemodal ways. Firstly, point isovists can be generated by ?clicking? onto any location in theenvironment. Secondly, all navigable space can be flood-filled with points, which may then beused to generate a field of isovists. Finally, a path of points can be used to examine howisovist properties vary along the path - the results of this can either be output as numericaldata, or exported as a series of pictures, which may be combined to form an animation of thevarying isovists along the route. This paper will examine all three modes of use in turn,starting from the simplest (point) to the more complex (the path). A description and equationfor all isovist measures used in the application will also be given as an appendix to thepaper

Path, theme and narrative in open plan exhibition settings

Three arguments are made based on the analysis of science exhibitions. First,sufficiently refined techniques of spatial analysis allow us to model the impact oflayout upon visitors' paths, even in moderately sized open plans which allow almostrandom patterns of movement and relatively unobstructed visibility. Second, newlydeveloped or adapted techniques of analysis allow us to make a transition frommodeling the mechanics of spatial movement (the way in which movement is affectedby the distribution of obstacles and boundaries), to modeling the manner in whichmovement might register additional aspects of visual information. Third, theadvantages of such purely spatial modes of analysis extend into providing us with asharper understanding of some of the pragmatic constrains within which exhibitioncontent is conceived and designed

The secret is to follow your nose: route path selection and angularity

This paper presents the results of an experiment in which route-choice decisions made bysubjects at road-junctions are recorded. It will then demonstrate that a route can be expressedas the sum of the individual decisions made or as the sum of all possible decisions available(i.e. potential choices) during a journey. The relationship between these two values will becompared statistically indicating that the decisions made at road-junctions correlate morestrongly with maximum angles of incidence of road-center-lines leading from a junctionthan to mean or minimum angles. One interpretation of this phenomenon is that subjectsappear to be attempting to conserve linearity throughout their journey. Since any theorybased upon the conservation of angular linearity appears to be refuted by certain, informalobservations of subjects traversing urban grids, the first theory put forward in this paper isthen modified to account for this particular case. The final hypothesis presented in this paperis based upon acts of rule-based decision-making combining principles of the conservationof linearity whilst minimising the angular difference between bearings. The two key bearingsare those of the direction of potential route choices compared to the perceived bearings ofthe wayfinding goal as judged from sequential instances of the observer's location. Thistheory of modified angular conservation is called 'The British Library Theory'.In (Conroy, 2001) it was demonstrated that the most popular routes from a sample(as calculated using string-matching techniques) also appeared to be more 'linear'. This observationreproduces similar findings made in (Golledge, 1995). The question that these observationsprompt is what route choices are individuals making at road junctions such that theiractions result in this apparent conservation of route linearity? Therefore, in this paper amethod is proposed for the determination of route choice decisions made at consecutiveroad junctions over the duration of a single journey. This method employs a measure ofangular deviation (from a straight line or direction) and uses this to develop a cumulativemeasure for an individual's entire journey, based upon the summation of all choices made atevery junction encountered along the route.The hypothesis that this method was developed to test is that an individual subjectwill follow as straight a route as possible with minimal angular deviation (from a straightline) on condition that this choice always approximates the direction of their final destination.Another way of stating this hypothesis is that essentially people 'follow their noses'whilst navigating through an environment

To tame a TIGER one has to know its nature:extending weighted angular integration analysis to the descriptionof GIS road-centerline data for large scale urban analysis

GIS databases representing urban layouts according to road centerlines spanningbetween intersection nodes (at road junctions) can be analyzed syntactically basedon the concept of angular fractional depth

Measuring environments for public displays: a Space Syntax approach

This paper reports on an on-going project, which is investigating the role that location plays in the visibility of information presented on a public display. Spatial measures are presented, derived from the architectural theory of Space Syntax. These are shown to relate to the memorability of words and images presented on different displays. Results show a complex pattern of interactions between the size and shape of spaces in which displays are situated and the memorability of different types of representations depicted. This approach offers a new way to consider the role of space in guiding and constraining interaction in real settings: a growing concern within HCI and Ubicomp