Search results for "spatial analysi"
showing 10 items of 208 documents
Scale-related patterns in the spatial and environmental components of stream macroinvertebrate assemblage variation
2007
Aim We examined the relative contributions of spatial gradients and local environmental conditions to macroinvertebrate assemblages of boreal headwater streams at three hierarchical extents: bioregion, ecoregion and drainage system. We also aimed to identify the environmental variables most strongly related to assemblage structure at each study scale, and to assess how the importance of these variables is related to regional context and spatial structuring at different scales. Location Northern Finland (62–68° N, 25–32° E). Methods Variation in macroinvertebrate data was partitioned using partial canonical correspondence analysis into components explained by spatial variables (nine terms…
Geographical Distribution of Unemployment: An Analysis of Provincial Differences in Italy
2007
Unemployment rates appear to vary widely at a subregional (e.g., local or provincial) level. Using spatial econometric models for spatial autocorrelation, this paper focuses attention on the spatial structure of regional unemployment disparities of Italian provinces. On the basis of findings from the economic literature and of the available socio-economic data, various model specifications including different explanatory variables are tested to investigate the geographical distribution of unemployment in the 103 provinces of Italy for the years 1998 and 2003. The results suggest that there is a clear explanation of unemployment differentials in terms of spatial equilibrium and disequilibriu…
Modelling the presence of disease under spatial misalignment using Bayesian latent Gaussian models.
2015
Modelling patterns of the spatial incidence of diseases using local environmental factors has been a growing problem in the last few years. Geostatistical models have become popular lately because they allow estimating and predicting the underlying disease risk and relating it with possible risk factors. Our approach to these models is based on the fact that the presence/absence of a disease can be expressed with a hierarchical Bayesian spatial model that incorporates the information provided by the geographical and environmental characteristics of the region of interest. Nevertheless, our main interest here is to tackle the misalignment problem arising when information about possible covar…
Poor prenatal care in an urban area: a geographic analysis.
2009
Abstract Poor prenatal care increases the risk of having a premature or low-birth-weight infant. Rates of poor prenatal care vary spatially, influenced not only by individual mothers’ characteristics but also by social neighborhood context and proximity to healthcare services. The aim of this article is to identify and map the spatial patterns of prenatal care and to analyze the spatial and social origins of such inequalities. Our study concerns 30,338 individuals who received antenatal care in a highly urbanized French district: Seine-Saint-Denis. The geographical distribution of poor prenatal care is revealed by exploratory spatial data analysis tools. This spatial clustering is related t…
Spatial history: railways, uneven development and population change in France and Great Britain, 1850-1914
2011
International audience; A comparative spatial history combining historical narrative, geographical thinking, and spatial analysis of historical data offers new perspectives on railway expansion and its effects in France and Great Britain during the long nineteenth century. Accessible rail transport in the rural regions of both countries opened new economic opportunities in agriculture, extractive industries, and service trades, helping to revitalize rural communities and decrease their rates of out-migration. In France, long-standing economic disparities between the developed north and the less-productive south gradually reduced. These conclusions are based, in part, on the use of historica…
Mapping the Distortions in Time and Space: The French Railway Network 1830–1930
2013
International audience; Accessibility is frequently used in transportation planning to measure the efficiency of new infrastructure in terms of travel time and population served. In this article, the authors apply accessibility concepts based on the geo-historical angle. The aim of this study is to investigate the relationships between population dynamics and the railway expansion from 1830 to 1930. Their approach considers a local scale composed of some 36,000 French communes for the demographic data and more than 28,000 kilometers for the railway network. The methodological framework of this database is based on historical geographic information systems completed by anamorphosis analysis.…
Full field of view super-resolution imaging via two static masks
2008
The usage of two static gratings for obtaining super resolved imaging dates back to the work by Bachl and Lukosz in 1967. However, in that approach, a severe reduction in the field of view was the necessary condition for improving the resolution. In this paper we present two approaches that are also based upon two static gratings but without the need to sacrifice in the field of view. The key idea for not paying with the field of view is performed in two ways: First, by using white light illumination that averages the ghost images obtained outside the region of interest since the positions of those images are wavelength dependent. Second, by using two random functions for the encoding and t…
Les exclus de la mobilité : de l'observation à la décision
2014
In contemporary societies, mobility is considered as a social norm necessary for integration. Conversely, immobility is often seen as the opposite. Therefore, it is associated with a significant risk of exclusion. An approach in terms of exclusion involves a sociological orientation. Nevertheless, this thesis follows a geographical approach. Thus, a first question emerges from this disciplinary position: immobility is it a geographical object? Furthermore, it is possible to consider the mobility and immobility as equivalent and not opposed. This means that their impact may not be reversed. This position engages a second question: the relationship between immobility and exclusion is it legit…
Modeling the influence of alternative forest management scenarios on wood production and carbon storage: A case study in the Mediterranean region
2016
Forest ecosystems are fundamental for the terrestrial biosphere as they deliver multiple essential ecosystem services (ES). In environmental management, understanding ES distribution and interactions and assessing the economic value of forest ES represent future challenges. In this study, we developed a spatially explicit method based on a multi-scale approach (MiMoSe-Multiscale Mapping of ecosystem services) to assess the current and future potential of a given forest area to provide ES. To do this we modified and improved the InVEST model in order to adapt input data and simulations to the context of Mediterranean forest ecosystems. Specifically, we integrated a GIS-based model, scenario …
A Two-layer Partitioning for Non-point Spatial Data
2021
Non-point spatial objects (e.g., polygons, linestrings, etc.) are ubiquitous and their effective management is always timely. We study the problem of indexing non-point objects in memory. We propose a secondary partitioning technique for space-oriented partitioning indices (e.g., grids), which improves their performance significantly, by avoiding the generation and elimination of duplicate results. Our approach is novel and of a high impact, as (i) it is extremely easy to implement and (ii) it can be used by any space-partitioning index. We show how our approach can be used to boost the performance of spatial range queries. We also show how we can avoid performing the expensive refinement s…