Daniel Czamanski

When and Where is a City Fractal

We present here an analysis of the development of the Tel Aviv metropolis by using the concept of fractals. The fractal dimension of the entire metropolis, and of its parts, was estimated as a function of time, from 1935 onwards. The central part and the northern tier are fractal at all times. Their fractal dimension increased with time. However, the metropolis as a whole can be said to be fractal only after 1985. There is a general tendency towards fractality, in the sense that the fractal dimension of the different parts converge towards the same value.

Occupational closure and immigrant entrepreneurship: Russian Jews in Israel

Abstract The recent wave of Jews emigrating from countries of the former Soviet Union to Israel has created structural conditions for immigrant entrepreneurship. The large size of the migrant population and its spatial concentration create a demand for services and products that can be provided by immigrants. This paper investigates the factors associated with intentions to open a small business in a sample of Jewish immigrants from the countries of the former Soviet Union. It was found that intentions to open a small business are related to previous business experience, education, income, and length of residence in the country. Immigrants become interested in entrepreneurship after learning that their prospects of finding a job in their profession are meager and explain their motivation to open a small business as being to increase their income. The findings seem to support the disadvantage theory that conceptualizes entrepreneurship as an adaptive mechanism to structural barriers in the primary labor market that create an occupational closure for immigrants possessing low and middle levels of education and income.

The Dynamics of the Tel Aviv Morphology

In this paper we suggest an approach for understanding the spatial behavior and structure of cities. It views cities as physical objects and is based on urban morphology alone. The units of examination are urban clusters instead of municipalities defined by politically determined boundaries. Clusters are defined as contiguous built-up urban areas. We present characteristics of clusters, including their morphology. Previous work that analyzed urban clusters focused on the Pareto distribution of clusters and on the behavior of the biggest cluster. Our work presents a more thorough description of the characteristics of urban clusters. By means of historic data of the Tel Aviv metropolis we present cluster statistics and we study their dynamics. We present characteristics of the clusters from 1935 to 2000, including their number, rank-size distribution, and morphology through the area–perimeter relation. These indicators present important anomalies in 1964 and 1985. Our study suggests that the urban cluster approach can be used as a tool to study urban phenomena and we hope that through them we shall be able to investigate economic and social phenomena as well.

Urban Sprawl and Ecosystems — Can Nature Survive?

Contrary to the popular notion that the advancing frontier of urban development has been swallowing and destroying natural ecosystems we present evidence that the sprawl of cities creates ample open space in peri-urban areas. Traditional view of city–nature dichotomy and clear spatial separation should be substituted by a vision that reflects the complex spatial dynamics of city–rural–natural fabric with extended areas of overlap among them. We present a survey of the relevant research concerning urban and ecological systems spatial dynamics and conclude that nonregular, leapfrogging spatial expansion, characteristic of the majority of the modern western cities, may buffer between urban and intensively cultivated agricultural areas and counter their impacts on natural ecosystems. The wealthy sprawling suburbs provide essential habitats for native species and ensure their survival.

Modeling Cities in 3D: A Cellular Automaton Approach

This paper presents a quasi-3D cellular automaton (CA) simulation model of cities. A 2D CA model includes a cell attribute that represents building height information. Dynamic processes are depicted using four parameters: initial building coverage, interaction with adjacent neighborhood, inertia, and noise. These parameters can assume simple economic interpretation. Some combinations of values of the parameters result in cities that experience paths of convergent growth. Some values lead to cities that experience phase transitions. We suggest a typology of resulting urban patterns and note the emergence of spatial clusters of high-rise buildings.

The connectivity of Haifa urban open space network

Urban open spaces are considered as spatial residuals of the expansion of built areas. The environmental impact of the resulting land-cover pattern and associated ecosystem services are frequently evaluated at a crude spatial resolution only. However, wild animals use remaining interconnected fine-grain open spaces as an infrastructure for movement. In this paper, we traced the evolution of an open-space system in Haifa, Israel, and examined the impact of urban morphology on size and distribution of open spaces at different spatial resolutions. At a 30 m resolution, our analysis indicated fragmentation and increasing partial elimination of open spaces. Over time the connectivity declined at a diminishing rate, yet the network did not disintegrate into separate components. The evolution analysis implied that in crude resolution, the open space network is threatened. At a 5 m resolution, our analysis showed that Haifa remains porous to animal movement. Using combined multiple least-cost paths through the urban landscape of heterogeneous permeability, we illustrated extensive connectivity among open spaces. Backyards and other urban in-between spaces complemented the seminatural open-space network connectivity, enabling wildlife movement between habitat patches and thus survival in an urbanized environment.

Can visibility predict location? Visibility graph of food and drink facilities in the city

Abstract The spatial arrangement of socio-economic facilities in the city is shaped by the interaction of many individuals in the context of a particular physical structure. The urban physical environment displays characteristics of networks (graphs) where nodes and edges are embedded in space. For decades, the analysis of urban network structure represents an attractive model for describing urban phenomena. This paper presents novel means of understanding how socio-economic activities are distributed in urban environment, what forces influence their spatial patterns and how urban structure and functions are mutually dependent. We investigate the functional aspect of urban spatial networks; specifically we study the spatial distribution of food and drink public facilities in the historical district of Tel Aviv-Yafo Israel. These places, cafés, coffee shops, restaurants and others are known as ‘third place’ in urban sociology and play an important role in establishing a sense of place. We propose a novel graph analytic framework in which the third places are incorporated by means of visual accessibility. The development of this framework emerged from the concept of Integrative Visibility Graph (IVG), a quantitative method, based on visibility analysis of urban structure and its functioning. Several centrality measures from complex network theory are applied to the proposed graphs in order to evaluate structural position of third place locations in the urban network. Our findings illustrate a strong correlation between street centrality values and third place distribution.

Vascular Plant Species Richness Patterns in Urban Environments: Case Studies from Hannover, Germany and Haifa, Israel

The continuous expansion and growth of urban and settled areas result in a mosaic of open spaces which provide important habitat for species. Species richness within the urban matrix has been commonly studied in relation to urban-rural gradients, where the richness in open-space patches has been evaluated with respect to their location along this gradient. In this study we propose that additional factors may drive richness properties, namely patch size. We established a comparative study, where species richness patterns were compared between Haifa and Hannover, with respect to two driving factors: open-area patch size and its distance from the urban edge. These relationships were assessed for the overall number of vascular plant species and for native species only. Patches were identified by classifying aerial photographs of the cities, and surveying 32 patches in Hannover and 37 patches in Haifa which were randomly selected from the delineated patches. Results indicate that in both cities distance from the urban edge was not a significant factor explaining either the total vascular plant richness in the patches, or the native species richness. In contrast, both classes of species richness were significantly related with patch size. R2 values for total richness were 53 % in Hannover and 45 % in Haifa. With respect to native species richness, patch size explained a higher proportion of the variance in Hannover where R2 = 73 %, and a lower proportion of the variance in Haifa (R2 = 33 %). These preliminary results indicate strikingly similar driving factors in two urban landscapes which are characterized by fundamentally different histories and environments.

Immigration and Home Ownership: Government Subsidies and Wealth Distribution Effects in Israel

A wealth‐building, egalitarian argument is persistently used to justify homeownership policies. This paper examines this argument in light of the Israeli housing market experience during the 1990s. Under the pressure of mass immigration from the former USSR, the governmental mortgage scheme evolved to misleadingly appears as a voucher system. This system reconciled two conflicting paradigms: (1) the commitment of Israel to serve as a safe haven for all Jewish people, (2) the rising belief in the merits of economic liberalization. This system proved to be effective in creating a construction boom, and in achieving high homeownership rate among immigrants. Yet, analyses presented in the paper suggest that it led to rapidly increasing prices, chaos and distortion in the housing market, and incurred high costs for small, disadvantaged groups.

Cities in competition, characteristic time, and leapfrogging developers

In a recent paper Czamanski and Roth (2011 Annals of Regional Science 46 101–118) demonstrated that, because the profitability of construction projects is influenced by variations in the time incidence of costs and revenues, despite declining willingness to pay and land gradients with distance from central business districts, profitability can experience local maxima away from urban centers. The time until the realization of revenues was termed ‘characteristic time’. Its size is the result of planning polices and can lead to leapfrogging and scattered development, especially when interest rates are low or negligible. We explained this result by modeling the simple behavior of developers in the context of a single linear city. In this paper we consider the case of two municipalities with different development policies and characteristic time functions. We explore local maxima in profitability, typical of disequilibrium situations, especially during periods when cities are growing. Myopic assumptions, in the sense that each city is interested only in what happens on its side of the municipal boundary, can easily lead to unintended leapfrogging. Competition between cities can result in intentional leapfrogging or in spatially concentrated development, depending on the policy objectives. We extend the analysis further and consider qualitatively different cities that give rise to different gravity-type forces and differences in willingness to pay. The demand and supply sides of the building market are integrated into the model. The additional considerations can lead to various patterns of scattered development capable of explaining the spatial structure of metropolitan areas.