1,720,962 research outputs found
“Geographical memories” in honour of Professor Yorgos Photis
Get PDFThis special issue, in honour of the beloved Teacher and Colleague, Professor Yorgos Photis, suggests a series of memories, expecting to follow the trace of his scientific way of thinking through the writings of his students and colleagues, honouring him and expressing our love and recognition. Professor Yorgos Photis typically followed the curriculum of the School of Rural, Surveying and Geoinformatics Engineering of National Technical University of Athens, teaching geography and spatial analysis as well as space syntax. In reality he substantially taught life itself with his dynamic personality, his graciousness and his gentility. The following scientific papers broaden the horizons of different geographical fields that he visioned and give further stimulus to continue his avant garde work on Geography at a national and international level. The reader can “walk” through geographical research that he supervised concerning spatial thinking and spatial analysis using GIS. This special issue is edited by the European Journal of Geography (EJG), of which he was the editor for many years as President of the Hellenic Geographical Society. I’m certain that the colleagues, the students and the graduates of the department having the luck and the honour to meet him, will continue his work inspired by his ethics and values
Residential Concentration Pattern Analysis and of Urban Cluster Dynamics Assessment.
Get PDFThe main aim of this paper is the definition of a methodological framework for the determination, analysis and cross-evaluation of urban clusters which are formulated within wider study areas, such as administrative regions. To this end, different methods and techniques are utilised, that stem from the fields of Statistics and Quantitative Spatial Analysis and which during the last years are all the more commonly applied to the different stages of Geographical Analysis. The definition of urban clusters is mainly based on different types of variables such as the demographic characteristics of the cities, the number of public facilities located in them, as well as the total length of the different types of road network in the study area. Furthermore a comparative indicator of spatial concentration is formulated that reflects the role and the relative weight of every urban area in the study region as well as its spatial influence. Such a metric, improves the definition and analysis of urban clusters and in the same time, constitutes an alternative assessment of their overall locational perspective. Both the proposed methodological framework and the formulated indicator are applied and in the region of Thessaly, Greece
Perceived safety and fear of crime: A web-based GIS platform
Get PDFFear of crime is a social phenomenon that mainly affects the population of urban communities and it is recognized as an issue by both the academic community and society itself. To study the phenomenon, it is necessary to collect primary data, either using traditional data collection methods or using well-established online questionnaires. This paper describes the process and architecture of developing an interactive data survey, analysis, and geovisualization web-based platform to support online questionnaires and surveys, related to the urban fear of crime. The main goal is to provide tools and utilities for researchers, journalists, groups or individuals, interested in the scientific aspect of fear of crime, to collect related data and analyze them within a common interface. The fear of crime platform utilizes a client-server Web-GIS application that gives access to a worldwide spatial database. As the fear of crime platform is a dynamic ecosystem that grows up every day, this database is also growing proportionally by individuals around the world. The project’s development is accessible at the following web address: www.fearofcrime.co
Urban clustering and residential concentration pattern assessment in a GIS environment. Application to the Region of Thessaly, Greece.
Get PDFThe main aim of this paper is the definition of a methodological framework for the determination, analysis and cross-evaluation of urban clusters which are formulated within wider study areas, such as administrative regions. To this end, different methods and techniques are utilised, that stem from the fields of Statistics and Quantitative Spatial Analysis and which during the last years are all the more commonly applied to the different stages of Geographical Analysis. In this regard, the four interconnecting components that form the proposed methodology are Cluster Analysis, Distance Counts, Location Quotient and Nearest Neighbour Analysis along with the analytical and presentational capabilities of G.I.S. technology. The definition of urban clusters is mainly based on different types of variables such as the demographic characteristics of the cities, the number of public facilities located in them, as well as the total length of the different types of road network in the study area. At its final state, the proposed methodological approach is strengthened by the formulation of a comparative indicator of spatial concentration reflecting the role and the relative weight of every urban area in the study region as well as its spatial influence. Such a metric, improves the definition and analysis of urban clusters and in the same time, constitutes an alternative assessment of their overall locational perspective. Both the proposed methodological framework and the formulated indicator are applied and in the region of Thessaly, Greece.
Combinatorial locational analysis of public services in metropolitan areas. Case study in the city of Volos, Greece.
Get PDFSocial prosperity largely depends on spatial structure, a relation which becomes stronger in urban areas where the quality of life is menaced by several factors. Traffic, over-building, lack of open space and deficient location of services come to the fore. The latter reflects access inequality and is one of the main reasons for everyday movement difficulties of citizens. Particularly, public services, as part of the public sector, are considered to be driven by the principle of social well-fare. Therefore the study of their location gives rise to the question: how can access of city blocks to public services be evaluated and how can the results of this evaluation be combined with the monetary values assigned by the state? In this respect, the main aim of this paper is the determination of a synthetic methodological framework for the locational analysis and evaluation of public services in urban areas. The proposed approach is based on spatial analysis methods and techniques as well as on the analytical capabilities of GIS and finally leads to the definition of the locational value for each city block. The public services are classified according to served population age groups and to their yearly utilization levels. The minimum and average Manhattan distances to the services of each classification group are calculated along with the percentages of services that are closer than a critical radius to each city block. At the final step, city blocks are classified through the use of cluster analysis to the calculated distances and percentages and then ranked according to their overall accessibility to public services. Their score is utilized in the definition of their locational value and in the formulation of a combinatorial index which compares locational and land values throughout the study area. The methodological framework is applied in the city of Volos where according to the results of the analytical process the majority of city blocks (60,7%) indicates a comparatively lower locational than monetary land value.
Space-Time Human Behaviour and Models of Locomotion: the Case of Students in the City of Volos, Greece
Get PDFThe problem of space-time human behaviour is currently a very active subject of research in the geography and transport literature. The main objective of this study is the investigation of the factors that configure the dynamics of in-the-city individual locomotion through the tracing of daily movements and with respect to a specific set of destination alternatives, originated by the place of residence. According to the proposed methodological framework, an activity-based model of daily locomotion of a specific socio-economic group can be defined through the combined utilisation of methods and techniques from the scientific fields of Use of Time and Spatial Analysis. In this respect, the application deals with the spatio-temporal analysis of diachronic daily locomotion and the definition of the space of activity through the determination of space-time intensity and concentrations and is based on questionnaire data obtained by students in the city of Volos, Greece.
Spatio-Temporal Point Pattern Analysis Using Genetic Algorithms
Get PDFThe effectiveness of emergency service systems is measured in terms of their ability to deploy units and personnel in a timely, and efficient manner upon an event’s occurrence. A typical methodology to deal with such a task is through the application of an appropriate location - allocation model. In such a case, however, the spatial distribution of demand although stochastic in nature and layout, when aggregated to a specific spatial reference unit, appears to be spatially structured or semi – structured. Aiming to exploit the above incentive, the spatial tracing and analysis of emergency incidents is achieved through the utilisation of Artificial Intelligence. More specifically, in the proposed approach, each location problem is dealt with at two interacting levels. Firstly, spatio-temporal point pattern of demand is analysed over time by a new genetic algorithm. The proposed genetic algorithm interrelates sequential events formulating moving objects and as a result, every demand point pattern is correlated both to previous and following events. Secondly, the approach provides the ability to predict, by means of an artificial neural network, how the pattern of demand will evolve and thus the location of supplying centres and/or vehicles can be optimally defined. The proposed neural network is also optimised through genetic algorithms. The approach is applied to Athens Metropolitan Area and the data come from Fire Department’s records for the years 2003-2004.
Evaluation of Public Service Networks’ Efficiency and Accessibility Levels in Urban Areas.
Get PDFTrips in urban areas from residence to different activities constitute a large amount of daily transportations. The study of these trips and especially those towards public sector services and by public transportation means is essential in order to evaluate the effectiveness of public networks planning. In this paper, both public services and public buses networks are studied in a joint framework in order to evaluate their spatial allocation association which reflects effective service of citizens’ daily trips. The proposed methodology utilizes GIS technology and spatial analysis methods and is applied to the city of Volos (Greece). In this framework, population of each building block is assigned to the closest bus station (destination) while each bus station (origin) is assigned to its closest public facility. Different service areas are defined for each station and public service and the proximity of all building blocks is calculated. Further processing of the resulting information leads to the quantification of the spatial relationship between demand (population) and supply (public services and bus stations) and therefore, to the evaluation of the efficiency and effectiveness levels of public networks in urban areas.
Defining a geographically weighted regression model of urban evolution. Application to the city of Volos, Greece
Get PDFThe main objective of this paper is the multivariate analysis of urban space and specifically with the use of data that refer to the level of city block. Part of the analysis has been the comparative assessment of multiple linear regression and geographically weighted regression (GWR) analysis as well as the application of the aforementioned methods in the study of the central district of the Volos metropolitan area. The city of Volos is an urban conglomeration of approximately 110.000 inhabitants, located at the middle-east of Greece and is considered to be in the upper extreme in the cities’ urban hierarchy in Greece. The results provide a response to a question raised by spatial scientists during the last decades: is there a way that regression analysis can reveal spatial variations of results and with respect to scale fluctuation? The use of classical multiple regression analysis provides a single result – equation for the entire area. On the other hand, geographically weighted regression analysis stems from the fact that the above result is inadequate to reflect the different relational levels among selected variables characterizing the entire area. New estimations with the use of GWR declare the existence of various sub-areas – divisions of the initial territory – formulating a set of equations that reveal the spatial variations of variable relations. The results of the application have well proved the dominance of the analysis in the local level towards the analysis in the global level, highlighting the existence of intense spatial differentiations of variables that “interpret” the rate of land values in the city. Moreover, the distinct spatial patterns that emerge throughout the entire area, establish an alternative approach of urban spatial phenomena interpretation and a new explanatory basis for the clarification of obscure relations.
- …
