Extending the automated zoning procedure to reconcile incompatible zoning systems

This paper concerns the problem of matching incompatible zonal geographies, for example in the context of comparing census outputs over time. The automated zoning procedure (AZP) proposed by Openshaw (1977) is reviewed and extended to permit its application to the intersection of two zonal systems. A population stress statistic is proposed which may be used in the extended AZP algorithm in order to maximise the match between two zonal geographies. An implementation of this approach is described, and illustrated by reference to UK Census dat

Automatically generated port hinterlands

Competition between ports depends on inland freight distribution and the spatial structure of the hinterland. With this, ports and port regions increasingly compete to serve distant hinterlands. In a European context, many researchers refer to the agglomeration of economic activity in the Rhine-Ruhr area and the ‘blue banana’ to explain the concentration of port activity in the Hamburg-Le Havre port range. Besides this, the incorporation of new member states in the European market has changed the structure of port hinterlands. In this paper we attempt to reveal the spatial structure of the hinterland of the Hamburg-Le Havre ports using automated zoning techniques. These techniques aggregate geographical areas in homogeneous clusters using spatial as well as content-related constraints. We use both economic characteristics of hinterland regions and variables which express the link between these regions and ports to create a new map of the port hinterland. Besides an improved insight in the spatial structure of the hinterland, this analysis delivers a set of areas which can be used in economic models. Indeed, creating an ‘optimal’ zoning is one of the strategies researchers employ to handle observational units with often arbitrary boundaries.

Zone design of specific sizes using adaptive additively weighted voronoi diagrams

Territory or zone design processes entail partitioning a geographic space, organized as a set of areal units, into different regions or zones according to a specific set of criteria that are dependent on the application context. In most cases, the aim is to create zones of approximately equal sizes (zones with equal numbers of inhabitants, same average sales, etc.). However, some of the new applications that have emerged, particularly in the context of sustainable development policies, are aimed at defining zones of a predetermined, though not necessarily similar, size. In addition, the zones should be built around a given set of seeds. This type of partitioning has not been sufficiently researched; therefore, there are no known approaches for automated zone delimitation. This study proposes a new method based on a discrete version of the adaptive additively weighted Voronoi diagram that makes it possible to partition a two-dimensional space into zones of specific sizes, taking both the position and the weight of each seed into account. The method consists of repeatedly solving a traditional additively weighted Voronoi diagram, so that each seed?s weight is updated at every iteration. The zones are geographically connected using a metric based on the shortest path. Tests conducted on the extensive farming system of three municipalities in Castile-La Mancha (Spain) have established that the proposed heuristic procedure is valid for solving this type of partitioning problem. Nevertheless, these tests confirmed that the given seed position determines the spatial configuration the method must solve and this may have a great impact on the resulting partition

Changing boundaries: Overcoming modifiable areal unit problems related to unemployment data in South Africa.

The longitudinal comparison of census data in spatial format is often problematic because of changes in administrative boundaries. Such shifting boundaries are referred to as the modifiable areal unit problem (MAUP). This article utilises unemployment data between 1991 and 2007 in South Africa to illustrate the challenge and proposes ways to overcome it. Various censuses in South Africa use different reporting geographies. Unemployment data for magisterial districts of census 1991 and 1996 were re-modelled to the 2005 municipal boundaries. This article showed that areal interpolation to a common administrative boundary could overcome these reporting obstacles. The results confirmed more accurate interpolations in rural areas with standard errors below 3300. Conversely, the largest errors were recorded in the metropolitan areas. Huge increases in unemployment between 1996 and 2001 statistics were also evident, especially in the metropolitan areas. Although such areas are more complex in nature, making it more difficult to accurately calculate census data, the increase in unemployment could also be the result of census taking methods. The article concludes that socio-economic data should be available at the smallest possible geographic area to ensure more accurate results in interpolation. It also recommends that new output areas be conceptualised to create a seamless database of census data from 1991 to 2011 in South Africa.NCS201

Measuring Spatial Dynamics in Metropolitan Areas

This paper introduces a new approach to measuring neighborhood change. Instead of the traditional method of identifying “neighborhoods†a priori and then studying how resident attributes change over time, our approach looks at the neighborhood more intrinsically as a unit that has both a geographic footprint and a socioeconomic composition. Therefore, change is identified when both as- pects of a neighborhood transform from one period to the next. Our approach is based on a spatial clustering algorithm that identifies neighborhoods at two points in time for one city. We also develop indicators of spatial change at both the macro (city) level as well as local (neighborhood) scale. We illustrate these methods in an application to an extensive database of time-consistent census tracts for 359 of the largest metropolitan areas in the US for the period 1990-2000.

Estado del arte en procesos de zonificacion

Los procesos de partición espacial implican la división de un espacio geográfico en diferentes unidades o zonas según un conjunto específico de criterios. En ámbitos relacionados con las ciencias geoespaciales, la delimitación de estas zonas se realiza por agrupación de otras unidades básicas de área existentes en el espacio de trabajo. En este artículo se ofrece una revisión de los métodos de solución diseñados para este tipo de problemas, comenzando por una introducción a las técnicas heurísticas y modelos matemáticos más utilizados desde los años 60, para finalizar describiendo los recientes algoritmos aplicados a diagramas de Voronoi. También se revisan las aplicaciones en las que se han implementado algunos de estos modelos, quedando patente que son herramientas diseñadas para el tratamiento de problemas específicos, dada la dificultad de diseñar modelos genéricos y versátiles para este tipo de particiones espaciales o zonificacione

Large social inequalities and low levels of socio-economic segregation in Vilnius

The city of Vilnius has experienced major shifts in occupational structure between 2001 and 2011 and at the same time there were major transitions in the housing market and suburbanization. The main aim of this chapter is to get more insight in recent socio-economic segregation processes in Vilnius. We used occupational groups as a proxy for socio-economic status, and census tract level data to measure segregation in Vilnius and its three main housing zones during 2001 and 2011. Notwithstanding the major economic and social changes of post-communist society, we found low levels of segregation and modest change during the last decade. Local patterns of segregation were explored using location quotient maps. The analyses illustrated a deepening social divide in the city between the relatively rich north and the poorer south of the city, but the inner city changes are somehow ambiguous. In this chapter we argue that the main factors of socio-spatial change in Vilnius are related to an exceptionally high share of housing estates in the city and the polycentric urban system of the country. Together with 'fast-track' reforms after 1990 this urban system gave a unique character to the current processes and patterns of segregation

Multiscale evaluation of an urban deprivation index : implications for quality of life and healthcare accessibility planning

Deprivation indices are widely used to identify areas characterized by above average social and/or material disadvantages. Especially spatial approaches have become increasingly popular since they enable decision makers to identify priority areas and to allocate their resources accordingly. An array of methods and spatial reporting units have been used to analyze and report deprivation in previous studies. However, a comparative analysis and assessment of the implications of the choice of the reporting unit for quality of life and health care accessibility planning is still missing. Based on a set of ten socioeconomic and health-related indicators, we constructed a weighted deprivation index for the urban area of Quito, Ecuador, using four different reporting units, including census blocks, census tracts, and two units based on the automatic zoning procedure (AZP). Spatial statistics and metrics are used to compare the resulting units, and a participatory expert-based approach is applied to evaluate their suitability for decision making processes. Besides structural differences regarding their size and shape, no strongly marked statistical or qualitative differences were found in the four analyzed spatial representations of deprivation. The four representations revealed similar spatial patterns of deprivation, with higher levels of deprivation in the peripheries of the city, especially in the southern and north-western parts. The study also suggests that census blocks, due to their fine spatial resolution, were considered most useful for quality of life and health care accessibility planning by local stakeholders.DK W 1237-N23(VLID)231661

Control of spatial discretisation in coastal oil spill modelling

Spatial discretisation plays an important role in many numerical environmental models. This paper studies the control of spatial discretisation in coastal oil spill modelling with a view to assure the quality of modelling outputs for given spatial data inputs. Spatial data analysis techniques are effective for investigating and improving the spatial discretisation in different phases of the modelling. Proposed methods are implemented and tested with experimental models. A new “Automatic Search” method based on GIS zone design principles is shown to significantly improve discretisation of bathymetric data and hydrodynamic modelling outputs. The concepts and methods developed in the study are expected to have general relevance for a range of applications in numerical environmental modelling