Itzhak Omer

Entity-Based Modeling of Urban Residential Dynamics: The Case of Yaffo, Tel Aviv

The dynamics of the ethnic residential distribution in the Yaffo area of Tel Aviv, which is jointly occupied by Arab and Jewish residents, is simulated by means of an entity-based (EB) model. EB models consider householders as separate entities, whose residential behavior is defined by the properties of the surrounding infrastructure and of other householders. The power of the EB approach lies in its ability to interpret directly different forms of decisionmaker behavior in the models terms. Several scenarios of residential interactions between members of local ethnic groups are compared on the basis of detailed georeferenced data taken from Israels 1995 Population Census. The model simulates very closely the residential dynamics during the period 1955–95; the importance of the qualitative aspects of residential choice, as captured by the EB approach, is demonstrated by this correspondence.

Spatial cognitive dissonance and sociospatial emergence in a self-organizing city

By conceiving the city as a self-organizing system, we highlight and examine three interrelated phenomena of residential sociospatial segregation in a city: the gap which exists between intentions, preferences, and motives, on the one hand, and actual spatial behavior, on the other; the existence and role of local regions of instability within an otherwise stable urban system; and the conjunction between these two phenomena and the processes related to the emergence of new sociospatial entities. We examine the interplay between these interrelated urban phenomena and illustrate their role in urban dynamics. The discussion throughout the paper is elaborated partly by reference to empirical evidences but mainly by means of ‘city games’ played on a heuristic model (City-2) designed specifically for this purpose. City-2 can be described as a two-layer model composed of a migration submodel, which describes the intercity and intracity migration movements, superimposed on a cellular automata (CA) submodel describing the dynamics of the urban landscape itself. City-2 elaborates on, and extends, two previous heuristic models designed by us: (a) City, which is a probabilistic CA simulation model designed to examine the sociospatial relations between large social groups in a city, and (b) City-1, a planning-oriented cell-space model which introduced, in addition to the sociocultural properties of individuals, their economic status and the changing land value surface of the city.

Evaluating accessibility using house-level data : A spatial equity perspective

This paper presents a framework for evaluating house-level accessibility to urban services based on detailed geo-referenced socio-demographic census data. The framework is applied to assess spatial equity regarding the accessibility of individuals and social groups to urban parks in the city of Tel Aviv. Availability of house-level data was found to be essential for identifying differential accessibility of social groups according to income and national-ethnic identity as well as for evaluating the validity of accessibility assessments based on traditional aggregated measurement at the administrative district level. Also discussed are data usability issues arising when employing local-scale geo-referenced census data, including the potential effect on decisions regarding allocation of local urban services as well as spatial equity practice and discourse.

The implications of inter-visibility between landmarks on wayfinding performance: An investigation using a virtual urban environment

We investigated the effect of inter-visibility conditions between landmark elements in a simulated 3D urban environment on wayfinding performance (the acquisition of spatial knowledge through direct experience within the simulated environment and navigation throughout this environment). Our experiment was conducted by means of a 3D virtual environment to test the effect of two properties of visibility conditions: the overlapping between the visual fields of two landmarks and the topological depth (length of visual chain) between these visual fields. The results show that a high degree of overlapping between the visual fields of an origin and a target landmark helps people perform wayfinding tasks, particularly in cases where the length of the visual chain is short (one-step topological depth).

Spatial topology and its structural analysis based on the concept of simplicial complex

This paper introduces a model that identifies spatial relationships for structural analysis based on the concept of simplicial complex. The spatial relationships are identified through overlapping two map layers, namely a primary layer and a contextual layer. The identified spatial relationships are represented as a simplical complex, in which simplices and vertices, respectively, represent two layers of objects. The model relies on the simplical complex for structural representation and analysis. To quantify structural properties of individual primary objects (or equivalently simplices), and the simplicial complex as a whole, we define a set of centrality measures by considering multidimensional chains of connectivity, i.e. the number of contextual objects shared by a pair of primary objects. With the model, the interaction and relationships with a geographic system are modeled from both local and global perspectives. The structural properties and modeling capabilities are illustrated by a simple example and a case study applied to the structural analysis of an urban system.

High-resolution census data: a simple way to make them useful

Recent population censuses have brought about arrays of high-resolution explicitly geo-referenced socio-economic data stored in the framework of Geographic Information Systems. Geography and social science are not prepared for these new urban databases, and this paper considers their potential for investigating residential distribution, based on the data of the 1995 Israeli Census of Population and Households. We focus on the methodological problems: understanding the phenomena, formal analysis, and statistical inference. The methods for mapping high-resolution data, establishing spatial relationships between them, analyzing neighborhood structure, and exploring the significance of the results are proposed and illustrated by examples of the cities of Tel-Aviv (pop. 350,000) and Ashdod (pop. 100,000).

Visual Analytics of Urban Environments using High-Resolution Geographic Data

High-resolution urban data at house level are essential for understanding the relationship between objects of the urban built environment (e.g. streets, housing types, public resources and open spaces). However, it is rather difficult to analyze such data due to the huge amount of urban objects, their multidimensional character and the complex spatial relation between them. In this paper we propose a methodology for assessing the spatial relation between geo-referenced urban environmental variables, in order to identify typical or significant spatial configurations as well as to characterize their geographical distribution. Configuration in this sense refers to the unique combination of different urban environmental variables. We structure the analytic process by defining spatial configurations, multidimensional clustering of the individual configurations, and identifying emerging patterns of interesting configurations. This process is based on the tight combination of interactive visualization methods with automatic analysis techniques. We demonstrate the usefulness of the proposed methods and methodology in an application example on the relation between street network topology and distribution of land uses in a city.

Agent-Based Modeling of Householders’ Migration Behavior and Its Consequences

The Agent-Based approach is the most promising among the modelling techniques developed in recent decades that apply to demography and the social sciences. The current paper considers this approach with respect to householder migration and dynamics of residential distribution. It begins with a characterization of different styles of AB modelling and proceeds with examples of AB models of residential behavior, ranging from Schelling-type abstract models to real-world simulations of the population dynamics of an urban region with a population of 30,000. The latter is investigated in depth.

Systematic Distortions in Cognitive Maps: The North American West Coast vs. the (West) Coast of Israel

This article suggests a second thought on two papers published in Cognitive psychology in 1978 and 1981. Both articles deal with systematic distortions in cognitive mapping and both are based on experiments conducted along the North American West Coast. The first, by Stevens and Coupe, deals with distortions due to hierarchical organization while the second, by Tversky, with distortions due to rotation. Our second thought follows a set empirical results from a study conducted along the (West) coast of Israel. These results suggest that the experiments, on the basis of which the above two forms of systematic distortions were determined, could have resulted from another form of systematic distortion that we term the edge effect.

Urban spatial configuration and socio-economic residential differentiation: The case of Tel Aviv

Abstract This paper compares the effect of two aspects of a city’s spatial configuration – spatial separation between areas and dissimilarity in spatial integration between areas – on socio-economic residential differentiation in the city of Tel Aviv, Israel. The integration analysis is based on the space syntax methodological–conceptual framework and focuses on Tel Aviv’s core, where the main socio-economic differentiations were identified. Obtained results indicate that socio-economic differentiation between areas correspond mainly with the level of spatial separation or segmentation between areas but much less with the level of dissimilarity characterizing their spatial integration. The empirical findings can be considered innovative in light of the fact that space syntax studies dealing with social differentiation in cities usually focus solely on spatial integration patterns. The research findings nonetheless support the theoretical understanding that the urban environment’s spatial configuration provides a fundamental condition for the creation and preservation of urban social residential differentiation.