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1.
The liberalisation of gambling in Australia has resulted in the dispersal of 200 000 electronic gaming machines (EGMs) across the country, generating substantial revenues for State governments and the gambling industry as well as causing significant gambling-related harm. While the spatial distribution of EGM venues has been shown to follow a gradient of community disadvantage, little is known about the distinctions between the venues themselves (i.e. pubs, clubs, and casinos), either in terms of the catchments they service or the harm they produce. To this end, we constructed a sexpartite typology of EGM venues in the Northern Territory of Australia derived from venue location and licensing variables. We also conducted a geocoded mail survey (n=7041) of households in three urban centres to describe the composition of markets and problem-gambling outcomes across the six venue categories in the typology. Venues in accessible locations and those with a higher numbers of EGMs, particularly casinos and clubs located near supermarkets, were most closely associated with gambling-related harm, even when differing player socio-demographics were accounted for. We argue that gambling risk is a function of the interaction of geographic accessibility to markets on the one hand and venue effects on the other. An understanding of the geography of EGM gambling may help improve supply-side approaches to regulation, as well as shed insights into contemporary urban processes within Australia's regional settlements.  相似文献   

2.
Illegal disposal of waste is a significant management issue for contemporary governments because of the hazards posed to both human and ecosystem health. Understanding the complex distribution pattern of illegal waste and the range of economic, environmental and social factors influencing this distribution is valuable for improving the effectiveness and efficiency of waste management efforts. This article examines the applicability of mapping illegal waste disposal in the Sunshine Coast (Queensland, Australia) through the identification and integration of predictive spatial data in a geographic information system. A statistical model of illegal waste disposal was developed using a binary logistic regression analysis to identify explanatory variables suitable for predicting the distribution of illegal waste. Five statistically significant explanatory variables were identified through this analysis: population density, primary land use, distance to the nearest road, waste facility and roadside amenity. The generated statistical model had a predictive success of 86.1% with all indicators suggesting good model fit (χ2 = 474.3, P = 0 with df = 22) across the study area. Standardised spatial data on each explanatory variable were combined using a weighted linear combination analysis and the results were classified into five categories from very low to very high illegal waste disposal potentials using the equal interval method. The resultant mapping identified 6.9% of the study area as having very high illegal waste disposal potential, and subsequent validation indicated that 32.9% of known illegal waste disposal sites were located within these areas.  相似文献   

3.
Hospital service areas (HSAs) are increasingly adopted as a basic analysis unit for health care studies. The popular Dartmouth HSAs were produced more than two decades ago, and the process was far from automated. This research uses a Huff-based model automated in a geographic information systems (GIS) environment to delineate HSAs. Based on the Florida State Inpatient Database (SID) in 2011, a best-fitting distance decay function is derived from the actual travel patterns of hospitalization and then fed into the Huff model to strengthen the model's theoretical foundation in individual spatial behavior. The HSAs derived from the Huff-based model are then compared to the traditional flow-based HSAs defined by the Dartmouth method and assessed in terms of self-containment and heterogeneity of internal socioeconomic structure and urbanicity. The Huff-based model requires fewer data and is easy to implement as an automated toolkit and thus has great potential for replication in other regions to define large-scale and consistent HSAs.  相似文献   

4.
This study aims to analyze and explain, from a locational perspective, differences in the performance of Wal-Mart and Kmart stores in the Greater Cincinnati Area. A modified Huff model, taking competition and agglomeration into consideration, is developed to estimate the potential sales of individual Kmart and Wal-Mart stores. Results show that the modified Huff model is capable of more accurately estimating individual store sales than traditional interaction models. This study also suggests that the selection of store locations partially explains the difference in performance between Kmart and Wal-Mart stores. The model is calibrated using data collected in 2003, and the validity of the model is supported by the latest development of the stores in Greater Cincinnati Area since 2003.  相似文献   

5.
Hydrological connectivity is a term often used to describe the internal linkages between runoff and sediment generation in upper parts of catchments and the receiving waters. In this paper, we identify two types of connectivity: direct connectivity via new channels or gullies, and diffuse connectivity as surface runoff reaches the stream network via overland flow pathways. Using a forest road network as an example of a landscape element with a high runoff source strength, we demonstrate the spatial distribution of these two types of linkages in a 57 km2 catchment in southeastern Australia. Field surveys and empirical modelling indicate that direct connectivity occurs primarily due to gully development at road culverts, where the average sediment transport distance is 89 m below the road outlet. The majority of road outlets were characterised by dispersive flow pathways where the maximum potential sediment transport distance is measured as the available hillslope length below the road outlet. This length has a mean value of 120 m for this catchment. Reductions in sediment concentration in runoff plumes from both pathways are modelled using an exponential decay function and data derived from large rainfall simulator experiments in the catchment. The concept of the volume to breakthrough is used to model the potential delivery of runoff from dispersive pathways. Of the surveyed road drains (n=218), only 11 are predicted to deliver runoff to a stream and the greatest contributor of runoff occurs at a stream crossing where a road segment discharges directly into the stream. The methodology described here can be used to assess the spatial distribution and likely impact of dispersive and gullied pathways on in-stream water quality.  相似文献   

6.
基于网络分析的城市影响区和城市群空间范围识别   总被引：4，自引：3，他引：1  
以不打破行政界线为前提,利用Huff模型,基于矢量数据,采用最短交通路网距离和城市综合规模值来综合测算腹地与中心城市之间的势能,根据势能确定腹地县域的归属,对全国地级及以上城市的空间影响范围进行识别,并和基于改进场强模型的城市影响腹地范围界定结果进行对比。以全国发育较成熟的15个城市群为对象,综合测定城市群的影响范围,并与城市群规划中的空间范围进行对比,提出城市群空间范围调整建议。并以长株潭城市群为例,通过社会网络分析方法,综合分析测定城市群的空间影响范围。研究结果可为城市(群)规划提供科学依据和方法参考。  相似文献   

7.
Ashwan Reddy 《Urban geography》2013,34(7):1099-1112
Residential overcrowding has remained a persistent, low-level phenomenon in the United States over the past 30 years, and has been linked to negative personal health outcomes. A household is typically considered overcrowded if it has more than one person per room (PPR). The PPR measure, however, ignores variations in room size and does not accurately measure residential living space. To remedy this issue, we introduce volume per capita (VPC), a new measure that combines census, land use and building data to quantify the amount of residential space per person in cubic footage. We find that VPC correlates with three distinct measures of PPR (r2 = 0.05–0.26), but has no relationship to population density. This suggests that PPR and VPC capture different aspects of living conditions, and that VPC provides a more direct measure residential space. In addition, because VPC can be calculated at the fine-grained spatial resolution of census blocks, it is an ideal measure by which to quantify residential space and understand overcrowding within metropolitan areas.  相似文献   

8.
对历届广交会的统计数据以及第109届广交会共2万多家国内参展企业的数据资料进行整理和分析,运用数理统计、地理集中指数( Index of Concentration)、吸引半径指数(Attractiveness Radius)、相关性分析等量化方法,从空间分析角度研究广交会吸引国内各地区、各行业企业参展的吸引力空间分布结构以及分布差异.结果表明:广交会对国内参展商的吸引力在空间上已经形成了广泛的覆盖;相同等级分布区(带)的省份(直辖市、自治区)表现出明显的空间连续性,不同等级的分布区(带)则呈现较显著的从  相似文献   

9.
The aim of this study was to evaluate four metrics to define the spatially variable (regionalised) hillslope sediment delivery ratio (HSDR). A catchment model that accounted for gully and streambank erosion and floodplain deposition was used to isolate the effects of hillslope gross erosion and hillslope delivery from other landscape processes. The analysis was carried out at the subcatchment (~ 40 km2) and the cell scale (400 m2) in the Avon-Richardson catchment (3300 km2), south-east Australia. The four landscape metrics selected for the study were based on sediment travel time, sediment transport capacity, flux connectivity, and residence time. Model configurations with spatially-constant or regionalised HSDR were calibrated against sediment yield measured at five gauging stations. The impact of using regionalised HSDR was evaluated in terms of improved model performance against measured sediment yields in a nested monitoring network, the complexity and data requirements of the metric, and the resulting spatial relationship between hillslope erosion and landscape factors in the catchment and along hillslope transects. The introduction of a regionalised HSDR generally improved model predictions of specific sediment yields at the subcatchment scale, increasing model efficiency from 0.48 to > 0.6 in the best cases. However, the introduction of regionalised HSDR metrics at the cell scale did not improve model performance. The flux connectivity was the most promising metric because it showed the largest improvement in predicting specific sediment yields, was easy to implement, was scale-independent and its formulation was consistent with sedimentological connectivity concepts. These properties make the flux connectivity metric preferable for applications to catchments where climatic conditions can be considered homogeneous, i.e. in small-medium sized basins (up to approximately 3000 km2 for Australian conditions, with the Avon-Richardson catchment being at the upper boundary). The residence time metric improved model assessment of sediment yields and enabled accounting for climatic variability on sediment delivery, but at the cost of greater complexity and data requirements; this metric might be more suitable for application in catchments with important climatic gradients, i.e. large basins and at the regional scale. The application of a regionalised HSDR metric did not increase data or computational requirements substantially, and is recommended to improve assessment of hillslope erosion in empirical, semi-lumped erosion modelling applications. However, more research is needed to assess the quality of spatial patterns of erosion depicted by the different landscape metrics.  相似文献   

10.
In this article we show that the Voronoi-based nine-intersection (V9I) model proposed by Chen et al. (2001, A Voronoi-based 9-intersection model for spatial relations. International Journal of Geographical Information Science, 15 (3), 201–220) is more expressive than what has been believed before. Given any two spatial entities A and B, the V9I relation between A and B is represented as a 3 × 3 Boolean matrix. For each pair of types of spatial entities that is, points, lines, and regions, we first show that most Boolean matrices do not represent a V9I relation by using topological constraints and the definition of Voronoi regions. Then, we provide illustrations for all the remaining matrices. This guarantees that our method is sound and complete. In particular, we show that there are 18 V9I relations between two areas with connected interior, while there are only nine four-intersection relations. Our investigations also show that, unlike many other spatial relation models, V9I relations are context or shape sensitive. That is, the existence of other entities or the shape of the entities may affect the validity of certain relations.  相似文献   

11.
Most of the literature to date proposes approximations to the determinant of a positive definite n × n spatial covariance matrix (the Jacobian term) for Gaussian spatial autoregressive models that fail to support the analysis of massive georeferenced data sets. This paper briefly surveys this literature, recalls and refines much simpler Jacobian approximations, presents selected eigenvalue estimation techniques, summarizes validation results (for estimated eigenvalues, Jacobian approximations, and estimation of a spatial autocorrelation parameter), and illustrates the estimation of the spatial autocorrelation parameter in a spatial autoregressive model specification for cases as large as n = 37,214,101. The principal contribution of this paper is to the implementation of spatial autoregressive model specifications for any size of georeferenced data set. Its specific additions to the literature include (1) new, more efficient estimation algorithms; (2) an approximation of the Jacobian term for remotely sensed data forming incomplete rectangular regions; (3) issues of inference; and (4) timing results.  相似文献   

12.
Terrain attributes such as slope gradient and slope shape, computed from a gridded digital elevation model (DEM), are important input data for landslide susceptibility mapping. Errors in DEM can cause uncertainty in terrain attributes and thus influence landslide susceptibility mapping. Monte Carlo simulations have been used in this article to compare uncertainties due to DEM error in two representative landslide susceptibility mapping approaches: a recently developed expert knowledge and fuzzy logic-based approach to landslide susceptibility mapping (efLandslides), and a logistic regression approach that is representative of multivariate statistical approaches to landslide susceptibility mapping. The study area is located in the middle and upper reaches of the Yangtze River, China, and includes two adjacent areas with similar environmental conditions – one for efLandslides model development (approximately 250 km2) and the other for model extrapolation (approximately 4600 km2). Sequential Gaussian simulation was used to simulate DEM error fields at 25-m resolution with different magnitudes and spatial autocorrelation levels. Nine sets of simulations were generated. Each set included 100 realizations derived from a DEM error field specified by possible combinations of three standard deviation values (1, 7.5, and 15 m) for error magnitude and three range values (0, 60, and 120 m) for spatial autocorrelation. The overall uncertainties of both efLandslides and the logistic regression approach attributable to each model-simulated DEM error were evaluated based on a map of standard deviations of landslide susceptibility realizations. The uncertainty assessment showed that the overall uncertainty in efLandslides was less sensitive to DEM error than that in the logistic regression approach and that the overall uncertainties in both efLandslides and the logistic regression approach for the model-extrapolation area were generally lower than in the model-development area used in this study. Boxplots were produced by associating an independent validation set of 205 observed landslides in the model-extrapolation area with the resulting landslide susceptibility realizations. These boxplots showed that for all simulations, efLandslides produced more reasonable results than logistic regression.  相似文献   

13.
This research examines changes to seasonal start dates (1948–2015) across urban locations in the eastern United States. For 25 cities, percentile-specific thresholds of temperature (Ta) and apparent temperature (AT) were used to define seasonal start dates. Seasonal changes were evaluated across four time periods: 0300, 0900, 1500, and 2100 UTC. Incorporating spatial and temporal variability into seasonal delineation, this research critiques the ways in which seasons are defined and builds on existing research regarding seasonal climate change. Both Ta and AT results generally indicate earlier starts to the summer and spring seasons, while the starts to winter and autumn seasons have been delayed. On average, a forward shift of 11 days was found for summer. Larger changes were found for AT thresholds when compared to air temperature alone. Temporally, the largest and most significant changes were found for the 0300 and 2100 observations. The observed changes to seasons have significant impact on a range of processes, including phenology and human health, and may be appropriate to consider further in future climatology studies.  相似文献   

14.
应用EUROSEM模型对三峡库区陡坡地水力侵蚀的模拟研究   总被引：10，自引：3，他引：7  
王宏  蔡强国  朱远达 《地理研究》2003,22(5):579-589
三峡库区坡地资源被广泛利用,但水土保持措施没有被很好地利用。坡地,尤其是陡坡地是库区主要泥沙来源,因此,有效评估土壤侵蚀风险、预测径流和侵蚀速率以及选择合理的水土保持措施在该地区显得非常必要。EUROSEM模型是动态分布式模型,可以在单独地块或小流域中预测水力侵蚀强度,其特点比较适合库区土壤侵蚀预测预报。本研究以在三峡库区秭归县王家桥小流域水土保持试验站的标准径流小区的人工降雨资料为基础,应用EUROSEM模型模拟陡坡地中的侵蚀状况。模拟结果表明,EUROSEM对人工降雨中径流模拟效果较好,但对土壤流失的模拟效果相对较差,更精确地模拟库区陡坡地的土壤侵蚀状况则需要作进一步的研究  相似文献   

15.
Social Network Analysis offers powerful tools to analyze the structure of relationships between a set of people. However, the addition of spatial information poses new challenges, as nodes are embedded simultaneously in network space and Euclidean space. While nearby nodes may not form social ties, ties may exist at a distance, a configuration ill-suited for traditional spatial metrics that assume adjacent objects are related. As such, there are relatively few metrics to describe these nuanced situations. We advance the burgeoning field of spatial social network analysis by introducing a set of new metrics. Specifically, we introduce the spatial social network schema, tuning parameter and the flattening ratio, each of which leverages the notion of ‘distance’ to augment insights obtained by relying on topology alone. These methods are used to answer the questions: What is the social and spatial structure of the network? Who are the key individuals at different spatial scales? We use two synthetic networks with properties mimicking the ones reported in the literature as validation datasets and a case study of employer–employee network. The methods characterize the employer–employee as spatially loose with predominantly local connections and identify key individuals responsible for keeping the network connected at different spatial scales.  相似文献   

16.
Closeness and betweenness are forms of spatial network analysis grounded in a long-standing tradition of measuring accessibility and flow potential. More recently, these measures have been enhanced by the concept of spatial localization, producing effective models for the prediction of pedestrian and vehicle driver behaviour.

A contradiction arises where the distance metric used to define locality does not match the distance metric used to define shortest paths for closeness and betweenness. A typical case is the use of angular shortest paths within a Euclidean buffer as a pedestrian flow model. Such a model assumes that people make a mode choice based on distance, but a route choice based on least angular change – even when this results in an excessively long ‘problem route’, which conflicts with their criterion for mode choice.

This study examines the prevalence of problem routes and the magnitude of their effect on some pedestrian and vehicle models. We show that while in a weighted analysis, pathological cases could invalidate an entire model, in the models presented the effect of this contradiction is minor. We do this by comparing model predictions to real flow data, using four strategies for handling problem routes: ignore, discard, reroute and strict locality. Strict locality is justified on the grounds of bounded rationality. We find all strategies to give broadly similar results, although the reroute and strict strategies give marginally better simulation accuracy. We also present a discussion of the characteristics of each strategy, and findings on computational efficiency.

We conclude that it is prudent in any computation of localized closeness and betweenness to consider the impact of problem routes; however, they do not necessarily invalidate these forms of analysis, which remain useful.  相似文献   

17.
Continuous depletion of groundwater levels from deliberate and uncontrolled exploitation of groundwater resources lead to the severe problems in arid and semi-arid hard-rock regions of the world. Geostatistics and geographic information system (GIS) have been proved as successful tools for efficient planning and management of the groundwater resources. The present study demonstrated applicability of geostatistics and GIS to understand spatial and temporal behavior of groundwater levels in a semi-arid hard-rock aquifer of Western India. Monthly groundwater levels of 50 sites in the study area for 36-month period (May 2006 to June 2009; excluding 3 months) were analyzed to find spatial autocorrelation and variances in the groundwater levels. Experimental variogram of the observed groundwater levels was computed at 750-m lag distance interval and the four most-widely used geostatistical models were fitted to the experimental variogram. The best-fit geostatistical model was selected by using two goodness-of-fit criteria, i.e., root mean square error (RMSE) and correlation coefficient (r). Then spatial maps of the groundwater levels were prepared through kriging technique by means of the best-fit geostatistical model. Results of two spatial statistics (Geary’s C and Moran’s I) indicated a strong positive autocorrelation in the groundwater levels within 3-km lag distance. It is emphasized that the spatial statistics are promising tools for geostatistical modeling, which help choose appropriate values of model parameters. Nugget-sill ratio (<0.25) revealed that the groundwater levels have strong spatial dependence in the area. The statistical indicators (RMSE and r) suggested that any of the three geostatistical models, i.e., spherical, circular, and exponential, can be selected as the best-fit model for reliable and accurate spatial interpolation. However, exponential model is used as the best-fit model in the present study. Selection of the exponential model as the best-fit was further supported by very high values of coefficient of determination (r 2 ranging from 0.927 to 0.994). Spatial distribution maps of groundwater levels indicated that the groundwater levels are strongly affected by surface topography and the presence of surface water bodies in the study area. Temporal pattern of the groundwater levels is mainly controlled by the rainy-season recharge and amount of groundwater extraction. Furthermore, it was found that the kriging technique is helpful in identifying critical locations over the study area where water saving and groundwater augmentation techniques need to be implemented to protect depleting groundwater resources.  相似文献   

18.
就近入学空间模型分析——以河南省巩义市初级中学为例   总被引：3，自引：0，他引：3  
从地理空间的角度理解我国义务教育就近入学政策与择校现象,引入空间模型模拟学校与居民点之间的供需关系,并尝试解释与择校现象密切相关的"热校"和"冷校"问题。使用最近距离模型、引力模型和Huff模型,以河南省巩义市50所初级中学和1 276个居民点为例,在ArcGIS软件中进行模型分析。在模型有效性检验的基础上,引入学校热度指标鉴别"热校"和"冷校",并统计各类学校的规模、生均资源分配和平均入学距离等指标。研究表明:Huff模型能较好地模拟义务教育供需现状;"热校"、"冷校"与其他学校的规模、生均资源和入学距离存在显著差异。该研究对于就近入学政策实施和学校布局调整具有参考价值。  相似文献   

19.

This paper investigates the determinants of spatial knowledge and how our knowledge of space varies according to geographic location. By using data on U.S. city names recalled at 22 test locations, a multivariate model of the information surface specific to each test location is calibrated. This model links the probability of a city being recalled from memory to its distance from the test site, its population size, its location with respect to other cities, and whether or not it is a state capital. The paper then suggests that these recall data provide information on spatial knowledge surfaces from which large-scale spatial choices, such as migration destinations, are made. Results from the analysis lend further evidence to the idea that spatial knowledge is stored and processed hierarchically and that individuals underrepresent information in large clusters. Consequently, the results have important implications for modeling any spatial behavior based on individuals' spatial information surfaces. In particular, the results cast further doubt on the validity of traditional large-scale spatial choice frameworks and lend support to the competing destinations hypothesis.  相似文献   

20.
Soil erosion by water (WSE) has become a relevant issue at the Mediterranean level. In particular, natural conditions and human impact have made the Calabria (southern Italy) particularly prone to intense WSE. The purpose of this investigation is to identify areas highly affected by WSE in Calabria by comparing the scenarios obtained by assuming control and preventive measures and actions, as well as actual conditions generated by forest fires, also in the presence of conditions of maximum rainfall erosion.Geographic Information System techniques have been adopted to treat data of reasonable spatial resolution obtained at a regional scale for application to the RUSLE model. This work is based on the comparison of such data with a basic scenario that has been defined by the present situation (present scenario). In this scenario: (i) R has been assessed by means of an experimental relation adjusted to Calabria on the basis of 5-min observations; (ii) K has been drawn from the soil map of Calabria including 160 soilscapes; (iii) LS has been estimated according to the RUSLE2 model by using (among other subfactors) a 40-m square cell DTM; (iv) C has been derived by processing the data inferred from the project Corine Land Cover, whose legend includes 35 different land uses on three levels; and (v) P has been hypothesized as equal to 1.For the remaining three hypothesized scenarios, the RUSLE factors have been adjusted according to experimental data and to data in the literature. In particular, forest areas subject to fire have been randomly generated as far as fire location, extension, structure, and intensity are concerned.The values obtained by the application of the RUSLE model have emphasized that land management by means of measures and actions for reducing WSE causes a notable reduction of the erosive rate decreasing from ~30 to 12.3 Mg ha− 1 y− 1. On the other hand, variations induced by hypothetical wildfires in forests on 10% of the regional territory bring WSE over the whole region to values varying from 30 to 116 Mg ha− 1 y− 1.This study can be offered to territorial planning authorities as an evaluation instrument as it highlights the merits and limitations of some territorial management actions. In fact, in Calabria no observations exist concerning the implications of these actions.  相似文献   

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