Narushige Shiode

3D urban models: Recent developments in the digital modelling of urban environments in three-dimensions

This paper reports on recent developments in the visualisation of urban landscapes. There is a growing interest in the contstruction of 3D models of urban and built environment for which a host of digital mapping and rendering techniques are being developed. This paper extracts some of the cases that we came across during worldwide interviews carried out in March 2000. Building on this review, we identify the range of data and techniques adopted for the development of 3D contents and how they could contribute to geographical analysis and planning of urban environment. A particular focus is given on the effectiveness of GIS and its related methods for their capacity to accommodate the demands for visual representation of urban environment as well as the basis for analysis and simulation.

Urban Planning, Information Technology, and Cyberspace

development of advanced information and telecommunications networks have created new kinds of socioeconomic activities, while changes in values and increases in cultural diversity within cities have made manifest the need for planning schemes based on flexibility and responsiveness to change. In contrast to motorization that completely altered the urban scene, IT has quietly merged into the existing urban structure, causing little change in appearance. Nevertheless, the exponential growth of the Internet and the increase in the use of computers have had profound effects on urban activities. Urban planners have responded by developing supportive tools such as network-based geographic information systems (GIS) as well as online public participation programs (PPP) and other types of groupware. These technologies automate data handling, reduce planning time, and increase the opportunity for public participation. The social life of cities has also been changing. There have been a diversity of life styles introduced into cities, and that also has created a need for more flexible planning schemes. The social challenge facing planners is to address the problems attendant upon the mixed culture of highly concentrated modern cities as well as the problems caused by spatial distortions resulting from the development of new HE technological advances and social changes that are characteristic of late twentieth-century urban centers have created the need for new strategies of urban planning. The

Detection of multi-scale clusters in network space

This paper proposes a new type of point‐pattern analytical method, Network‐Based Variable‐Distance Clumping Method (NT‐VCM), to analyse the distribution pattern of point objects and phenomena observed on a network. It is an extension of Planar Variable‐Distance Clumping Method (PL‐VCM) that was previously defined for point pattern analysis in Euclidian space. The purpose for developing NT‐VCM is to identify point agglomerations across different scales called multi‐scale network‐based clumps among distributed points along a network. The paper first defines a network‐based clump as a set of points where all its elements are found within a certain shortest‐path distance from at least one other element of the same set. It then proposes NT‐VCM as a technique to extract statistically significant multi‐scale clumps on a network. The paper also proposes an efficient algorithm for computing NT‐VCM, which involves the use of the Voronoi diagram, the Delaunay diagram and the minimum spanning tree that are adapted and newly extended for the purpose of analysis on a network. A comparative study of NT‐VCM and PL‐VCM using commercial facility data reveals a notable difference in the location as well as the size of the significant multi‐scale clumps detected in the both cases. Results from the empirical study confirm that NT‐VCM accounts for the actual network distance between the points, thus providing a more accurate description of point agglomerations along the network than PL‐VCM does.

The impact of online shopping demand on physical distribution networks: a simulation approach

Purpose – The purpose of this paper is to study how cost efficiency and the reliability of a physical distribution network are affected by changes in online shopping demand and to suggest how logistics service providers can respond to such changes.Design/methodology/approach – Based on a discrete event simulation approach, possible adaptive measures to online shopping demand increase are tested at three levels of decision making in parcel distribution network: priority assignment in the main hub (operational), introduction of sub‐hubs (tactical), and increase in the hub‐terminal capacity (strategic). The feasibility of the simulation is tested with parameters adopted from the logistics service data of an existing major parcel carrier in South Korea.Findings – Findings from the simulation model suggest that the existing physical distribution network can improve its cost efficiency and service reliability by evolving into a more centralized network structure with increased capacity of transshipment faciliti...

Network-based space-time search-window technique for hotspot detection of street-level crime incidents

This study proposes a street-level space‐time hotspot detection method to analyse crime incidents recorded at the street-address level and provides description of the micro-level variation of crime incidents over space and time. It expands the notion of search-window techniques widely used in crime science by developing a method that can account for the spatial‐temporal distribution of crime incidents measured in network distance. The study first describes the methodological framework by presenting the concept of a new type of search window and how it is used in the process of statistical testing for detecting crime hotspots. This is followed by analyses using (1) a simulated distribution of points along the street network, and (2) a set of real street-crime incident data. The simulation study demonstrates that the proposed method is effective in identifying space‐time hotspots, which include those that are not detected by a non-temporal method. The empirical analysis of the drug markets and assaults in downtown Buffalo, New York, revealed a detailed space‐time signature of each type of crime, highlighting the recurrent nature of drug dealing at specific locations as well as the sporadic tendency of assault incidents.

Street-level Spatial Interpolation Using Network-based IDW and Ordinary Kriging

This study proposes network-based spatial interpolation methods to help predict unknown spatial values along networks more accurately. It expands on two of the commonly used spatial interpolation methods, IDW (inverse distance weighting) and OK (ordinary kriging), and applies them to analyze spatial data observed on a network. The study first provides the methodological framework, and it then examines the validity of the proposed methods by cross-validating elevations from two contrasting patterns of street network and comparing the MSEs (Mean Squared Errors) of the predicted values measured with the two proposed network-based methods and their conventional counterparts. The study suggests that both network-based IDW and network-based OK are generally more accurate than their existing counterparts, with network-based OK constantly outperforming the other methods. The network-based methods also turn out to be more sensitive to the edge effect, and their performance improves after edge correction. Furthermore, the MSEs of standard OK and network-based OK improve as more sample locations are used, whereas those of standard IDW and network-based IDW remain stable regardless of the number of sample locations. The two network-based methods use a similar set of sample locations, and their performance is inherently affected by the difference in their weight distribution among sample locations.

3D spatial-temporal GIS modeling of urban environments to support design and planning processes

Visualization methods have been used by planners for many years, especially in the form of 3D visualization in design and 2D GIS in visualization and spatial analysis. The existing range of visualization methods, however, focuses primarily on the static state: it provides a representation of the urban environment at one particular point in time, usually using the most recent data-set available. This study attempts to build a 3D spatial-temporal GIS model of an urban environment to help study changes in the physical form of cities. The model treats time and space as mutually constitutive factors, thus allowing us to visualize the dynamic transition of an urban landscape: the way an urban area evolves over a period of time, including the growth and changes of street patterns, the sizes and shapes of buildings, and area density, as well as the general life cycle of a city as a whole.

Recursive Voronoi Diagrams

This paper introduces procedures involving the recursive construction of Voronoi diagrams and Delaunay tessellations. In such constructions, Voronoi and Delaunay concepts are used to tessellate an object space with respect to a given set of generators and then the construction is repeated every time with a new generator set, which comprises members selected from the previous generator set plus features of the current tessellation. Such constructions are shown to provide an integrating conceptual framework for a number of disparate procedures, as well as extending the existing functionality of the basic Voronoi and Delaunay procedures to variable spatial resolutions. Further, because they are shown to be fractal in nature, it is suggested that this characteristic can be exploited in the development of new strategies for spatial modelling.

Urban and rural geographies of aging: a local spatial correlation analysis of aging population measures

The spatial distribution of aging populations is commonly measured with either the aging population ratio or the aging population density. Used in isolation, however, these measures may fail to detect aging communities in certain types of urban or rural setting. This study uses both indices simultaneously to identify types and locations of aging communities more accurately. We investigate the spatial distribution of these communities using a standard correlation analysis and bivariate local spatial statistic analysis. Empirical analysis of geospatial data of the Aichi Prefecture in Japan suggests that using both indices allows us to capture different types of aging communities in diverse contexts (e.g. depopulated rural areas, pockets of aging communities in urban areas, and growing concentrations of aging population in the suburbs). The analysis uses data sets aggregated at different areal scales, confirming the generally stable nature of the outcome, despite some scale sensitivity.

Space-time characteristics of micro-scale crime occurrences: an application of a network-based space-time search window technique for crime incidents in Chicago

This study investigates patterns of micro-scale concentrations of different types of crime using the network distance in the spatial, temporal and spatial-temporal dimensions to enable an accurate description of the micro-scale geospatial variation of crime incidents. It applies a recently developed hotspot detection method that uses a network-based space-time search window technique. The method is refined by adopting the false discovery rate controlling procedure for the multiple testing problem. Empirical analysis uses individual street-address records of robbery, burglary, drug and vehicle theft incidents in a high-crime neighbourhood of Chicago in the year 2000. The study revealed a fine-scale, street-address-level space-time signature for each type of crime. Drugs and robbery formed stable space-time hotspots in specific locations, highlighting their recurrent nature. Burglary was characterised by a small set of short-term outbursts across space and time, and vehicle thefts showed little sign of concentrations. Comparing these results against their spatial signature helped identify different types of hotspots such as persistent warm spots and a hotspot consisting of a short-term outburst.The result demonstrates the significance of the street-level analysis from the microscopic perspective, which can help form a more focused policing tactic.