Road Network Distance Research Articles

A Hybrid Model for Forecasting Traffic Flow: Using Layerwise Structure and Markov Transition Matrix

Forecasting the traffic flow is greatly significant for traffic safety, energy conservation, and environmental protection. However, in the face of many external uncertainties, making accurate predictions about traffic volumes is a challenging issue. Many previous types of researche only explore the utility of a single factor in their prediction and rarely conduct the multi-factor research. As for the traffic flow prediction, many past types of researche focus primarily on the temporal distribution of the traffic flow on a single point on the road, ignoring the spatial correlation. In terms of global forecasting, it was logically far-fetched to mechanically view traffic as images. In this paper, considering the effects of many exogenous variables and the interaction between monitor sites, we propose a hybrid model to simultaneously predict the traffic flow in multiple positions by combining the layerwise structure and the Markov transition matrix (MTM). More specifically, we employ the layerwise structure to capture the periodicity, trend, and nonlinearity characteristics of traffic flow and, then, generate the MTM that captures the dynamics embodied in the data and produces the corresponding distributions. Considering the spatial correlation of traffic data, the real road network distance was thus introduced in our model. We apply the methodology on the real-world traffic data from Xiamen, and the experimental results show that the satisfactory predictions can be achieved using our model, which demonstrates the value of the transition matrix in traffic forecasts. In addition, we also introduce the point of interest and analyze its impact on the prediction results.

Built Environment, Psychosocial Factors and Active Commuting to School in Adolescents: Clustering a Self-Organizing Map Analysis.

Although the built environment and certain psychosocial factors are related to adolescents’ active commuting to and from school (ACS), their interrelationships have not been explored in depth. This study describes these interrelationships and behavioral profiles via a self-organizing map (SOM) analysis. The sample comprised 465 adolescents from the IPEN (International Physical Activity and the Environment Network) Adolescent study in Valencia, Spain. ACS, barriers to ACS, physical self-efficacy, social support and sociodemographics were measured by questionnaire. Street-network distance to school, net residential density and street intersection density were calculated from the Geographic Information System. The clustering of the SOM outcomes resulted in eight areas or clusters. The clusters which correspond to the lowest and highest ACS levels were then explored in depth. The lowest ACS levels presented interactions between the less supportive built environments (i.e., low levels of residential density and street connectivity in the neighborhood and greater distances to school) and unfavorable psychosocial variables (i.e., low values of physical self-efficacy and medium social support for ACS) and good access to private motorized transport at home. The adolescents with the lowest ACS values exhibited high ACS environment/safety and planning/psychosocial barrier values. Future interventions should be designed to encourage ACS and change multiple levels of influence, such as individual, psychosocial and environmental factors.

Analyzing spatial distribution and accessibility of primary schools in Bishoftu Town, Ethiopia

Education is a major force in economic, social and cultural empowerment. Primary education is compulsory, and the first stage in the education system of Ethiopia, and urges the provision of accessible service. However, presently, it is unclear that how well the services have been distributed and accessed in Bishoftu town, Ethiopia. For this primary schools in the town are considered and their spatial distribution and accessibility to the residents are explored using geographic information system as a tool for analysis. Location quotient and nearest neighbor analysis have been used to analyze spatial concentration and spatial distribution pattern of the schools, respectively. Computing service areas using road network distance and population density, the spatial accessibility of the schools has been compared and contrasted with standards in planning guide. As a result, inequality of service provision between neighboring areas in the town is found and the overall spatial distribution of the schools shows a clustered pattern. In addition, 23.9% of the residents are expected to travel more than twice of the maximum standard distance, indicates the current service provision is inadequate. The limitation is due to the combined effect of population distribution, spatial variables, socio-economic, and absence of regular monitoring and evaluation. The study would support the planning efforts being made to improve service provision, and it helps the government in formulating effective policies to the context.

Developing openly accessible health indicators for small areas in Great Britain: an observational study

BackgroundPublic health has long been concerned with understanding how the accessibility of individuals to certain environmental features can influence health and wellbeing. Such insights are increasingly being adopted by policy makers for designing healthy neighbourhoods. We aimed to use small area national level data to support and inform decision making about effects of environmental features on health. MethodsMeasures were selected by a scoping review of geographical determinants of health. Road network distance for every postcode centroid in Great Britain to its nearest outlet postcode centroid (for ten retail and health-related services) was calculated. These results were aggregated to lower super output areas. We also created measures of green space (amount of green space within a 900 m2 buffer) and concentrations of air pollutants (nitrogen dioxide, sulphur dioxide, and particulate matter less than 10 μm in diameter). Data were validated through field observations. An index (Access to Healthy Assets and Hazards) was also developed to summarise all the indicators into an overall measure of how healthy neighbourhoods are. Outcomes were point estimates of distance to nearest service, or level of green space or air pollution, and an overall score summarising these values for the index. FindingsIndividuals were located nearest to health services (eg, median distance to a general practice was 1·05 km, IQR 0·65–1·79), although they were just as near to many health negating outlets (eg, pubs 1·12, 0·64–1·99). Wide social inequalities were observed; for example, mean distance to a fast food outlet in the most deprived decile of areas in England was 1·17 km (95% CI 1·17–1·22) compared with 2·42 (2·35–2·49) in the least deprived decile. Access to Healthy Assets and Hazards identified suburban regions as the healthiest environments, and inner city and isolated rural areas as the least healthy. InterpretationOur open source suite of measures offers a useful resource for understanding the accessibility of small areas to positive and negative features of environments. We extend previous approaches towards designing health-related indicators by creating a multidimensional index, which has been incorporated into Public Health England's FingerTips system. FundingEconomic and Social Research Council (grant no ES/L011840/1). The funder had no role in the research.

Efficient continuous top-k geo-image search on road network

With the rapid development of mobile Internet and cloud computing technology, large-scale multimedia data, e.g., texts, images, audio and videos have been generated, collected, stored and shared. In this paper, we propose a novel query problem named continuous top-$k$ geo-image query on road network which aims to search out a set of geo-visual objects based on road network distance proximity and visual content similarity. Existing approaches for spatial textual query and geo-image query cannot address this problem effectively because they do not consider both of visual content similarity and road network distance proximity on road network. In order to address this challenge effectively and efficiently, firstly we propose the definition of geo-visual objects and continuous top-$k$ geo-visual objects query on road network, then develop a score function for search. To improve the query efficiency in a large-scale road network, we propose the search algorithm named geo-visual search on road network based on a novel hybrid indexing framework called VIG-Tree, which combines G-Tree and visual inverted index technique. In addition, an important notion named safe interval and results updating rule are proposed, and based on them we develop an efficient algorithm named moving monitor algorithm to solve continuous query. Experimental evaluation on real multimedia dataset and road network dataset illustrates that our solution outperforms state-of-the-art method.

Mining optimal meeting points for moving users in spatio-temporal space

Scheduling a meeting is a difficult task for people who have overbooked calendars and often have many constraints. This activity becomes further complex when the meeting is to be scheduled between parties who are situated in geographically distant locations of a city and have varying traveling patterns. To achieve this, we first propose a solution to determine optimal meeting location for two moving users in the Euclidean space. Then, we generalize the problem by considering variable number of moving users and evaluate optimal meeting point on the road network. We extend the work of Yan et al. (Proc VLDB Endow 4(11):1–11, 2011) in this domain by incorporating some real life constraints like variable number of users, varying travel patterns, flexible meeting point and considering road network distance. Experiments are performed on a real-world dataset and show that our method is effective in stated conditions.

Shp2graph: Tools to Convert a Spatial Network into an Igraph Graph in R

In this study, we introduce the R package shp2graph, which provides tools to convert a spatial network into an ‘igraph’ graph of the igraphR package. This conversion greatly empowers a spatial network study, as the vast array of graph analytical tools provided in igraph are then readily available to the network analysis, together with the inherent advantages of being within the R statistical computing environment and its vast array of statistical functions. Through three urban road network case studies, the calculation of road network distances with shp2graph and with igraph is demonstrated through four key stages: (i) confirming the connectivity of a spatial network; (ii) integrating points/locations with a network; (iii) converting a network into a graph; and (iv) calculating network distances (and travel times). Throughout, the required R commands are given to provide a useful tutorial on the use of shp2graph.

The impact of metro accessibility on residential property values: An empirical analysis

This paper investigates the influence of metro accessibility on Xi'an residential property values. The key finding is that proximity to metro stations tends to have a positive but nonlinear effect. Within two-kilometre road network distances from metro stations, property value uplift is lowest in areas immediately adjacent to metro stations, explained by negative externalities around metro stations outweighing accessibility gains. The highest effect is revealed at distances between 300 and 1200 metres away from stations. Other significant influences include the distance to the central business district, the size of the property, the age of the property, interior decoration, residential building type and geographical location. The evidence suggests that the catchment area size should be adjusted according to access mode shares. Policy implications are also provided for potential future decision making.

Urban foodscape trends: Disparities in healthy food access in Chicago, 2007–2014

We investigated changes in supermarket access in Chicago between 2007 and 2014, spanning The Great Recession, which we hypothesized worsened local food inequity. We mapped the average street network distance to the nearest supermarket across census tracts in 2007, 2011, and 2014, and identified spatial clusters of persistently low, high or changing access over time. Although the total number of supermarkets increased city-wide, extremely low food access areas in segregated, low income regions did not benefit. Among black and socioeconomically disadvantaged residents of Chicago, access to healthy food is persistently poor and worsened in some areas following recent economic shocks.

Population characteristics and geographic coverage of primary care facilities

BackgroundThe location of General Practitioner (GP) facilities is an important aspect in the design of healthcare systems to ensure they are accessible by populations with healthcare needs. A key consideration in the facility location decision involves matching the population need for the services with the supply of healthcare resources. The literature points to several factors which may be important in the decision making process, such as deprivation, transportation, rurality, and population age.MethodsThis study uses two approaches to examine the factors associated with GP accessibility in Northern Ireland. The first uses multinomial regression to examine the factors associated with GP coverage, measured as the proportion of people who live within 1.5 km road network distance from the nearest GP practice. The second focuses on the factors associated with the average travel distance to the nearest GP practice, again measured using network distance. The empirical research is carried out using population and geospatial data from Northern Ireland, across 890 Super Output Areas and 343 GP practices.ResultsIn 19% of Super Output Areas, all of the population live within 1.5 km of a GP practice, whilst in 24% none of the population live within 1.5 km. The regression results show that there are higher levels of population coverage in more deprived areas, smaller areas, and areas that have more elderly populations. Similarly, the average travel distance is related to deprivation, population age, and area size.ConclusionsThe results indicate that GP practices are located in areas with higher levels of service need, but also that care needs to be taken to ensure rural populations have sufficient access to services, whether delivered through GP practices or through alternative services where GP practices are less accessible. The methodology and results should be considered by policy makers and healthcare managers when making decisions about GP facility location and service provision.

Distance from public transportation and physical activity in Japanese older adults: The moderating role of driving status.

Although previous studies have shown that good access to public transportation is positively related with physical activity, the moderators of this relationship have not been explored sufficiently in older adults. It is possible that driving status could moderate this relationship. The present study examined whether the objectively measured distance between public transportation and the home was associated with physical activity levels, and whether this association was moderated by driving status among Japanese older adults. In this cross-sectional study, participants (n = 2,878) completed questionnaires and wore accelerometers for at least 7 days, to measure their average daily step counts and minutes spent engaging in moderate-to-vigorous physical activity. Road network distances between the home and the nearest bus stop or train station were measured using geographic information systems. Driving status was assessed using questionnaires. Multiple regression analyses stratified by driving status revealed that, among nondrivers, living further away from public transportation was associated with higher step counts (β = 0.08, p < .001) and moderate-to-vigorous physical activity (β = 0.06, p = .029). Among drivers, living closer to public transportation was significantly associated with higher moderate-to-vigorous physical activity levels (β = -0.05, p = .042). Despite the small effect sizes, the direction of the association between distance from public transportation and physical activity was different for current drivers and nondrivers. These findings imply that good access to public transportation does not positively relate with greater engagement in physical activity among nondriving older adults. Shorter distances to public transportation might reduce opportunities for engaging in physical activity for them. (PsycINFO Database Record

Are Perceived and Objective Distances to Fresh Food and Physical Activity Resources Associated with Cardiometabolic Risk?

Perceived and objective measures of neighbourhood features have shown limited correspondence. Few studies have examined whether discordance between objective measures and individual perceptions of neighbourhood environments relates to individual health. Individuals with mismatched perceptions may benefit from initiatives to improve understandings of resource availability. This study utilised data from n = 1491 adult participants in a biomedical cohort to evaluate cross-sectional associations between measures of access (perceived, objective, and perceived-objective mismatch) to fruit and vegetable retailers (FVR) and public open space (POS), and clinically-measured metabolic syndrome and its component risk factors: central obesity, dyslipidaemia, hypertension and pre-diabetes/diabetes. Access measures included perceived distances from home to the nearest FVR and POS, corresponding objectively-assessed road network distances, and the discordance between perceived and objective distances (overestimated (i.e., mismatched) distances versus matched perceived-objective distances). Individual and neighbourhood measures were spatially joined using a geographic information system. Associations were evaluated using multilevel logistic regression, accounting for individual and area-level covariates. Hypertension was positively associated with perceived distances to FVR (odds ratio (OR) = 1.14, 95% confidence interval (CI) = 1.02, 1.28) and POS (OR = 1.19, 95% CI = 1.05, 1.34), after accounting for covariates and objective distances. Hypertension was positively associated with overestimating distances to FVR (OR = 1.36, 95% CI = 1.02, 1.80). Overestimating distances to POS was positively associated with both hypertension (OR = 1.42, 95% CI = 1.11, 1.83) and dyslipidaemia (OR = 1.25, 95% CI = 1.00, 1.57). Results provide new evidence for specific associations between perceived and overestimated distances from home to nearby resources and cardiometabolic risk factors.

Safe-Region Generation Method for Versatile Continuous Vicinity Queries in the Road Network Distance

Safe-Region Generation Method for Versatile Continuous Vicinity Queries in the Road Network Distance

Are public open space attributes associated with walking and depression?

Public open spaces (POS) are key neighbourhood destinations shown to confer numerous physical and mental health benefits. The amount and spatial distribution of POS throughout cities are guided by urban planning policies and standards. However, empirical evidence is not generally used to create POS standards. Developing and testing POS indices associated with positive health outcomes, can inform evidence-based POS urban design and planning standards that support the creation of healthier cities. This study examined associations of urban design policy-derived and empirical measures of POS proximity and density with walking and depression. The 2011–12 Australian Diabetes, Obesity and Lifestyle study (AusDiab) wave data were used. Adults living in metropolitan Melbourne, Australia were included (n=319). Participants reported walking for recreation and any walking within their neighbourhood during the last week. Depression was calculated using the Center for Epidemiologic Studies Short Depression Scale (CESD-10). Informed by Australian urban design policies and empirical evidence, various POS measures were calculated at different street network distances around residential addresses using geographic information systems software. Measures tested included: distance to nearest POS, size of nearest POS, total number of POS, and area of POS at scales of 400, 800, 1000, and 1600m. Associations of these POS measures with walking and depression were examined using adjusted multilevel logistic regression models. Overall 68% and 77% of participants reported walking for recreation and any walking in the past week, respectively; and about 13% were categorized as depressed. Living within 400m of POS was not associated with either type of walking, but those whose nearest POS was >1.5ha had 1.90 and 2.66 times greater odds of walking for recreation and any walking during the last week, respectively. In Melbourne, the urban design policy standard is that POS be available within 400m of homes. In our study, this standard was not associated with walking or depression; however having a larger POS nearby supported residents' walking. This study highlights the importance of assessing such standards for their potential health impact, and warrants further investigation.

SKQAI: A novel air index for spatial keyword query processing in road networks

Spatial keyword query (SKQ) processing is gaining great interest with the proliferation of location-based devices and services. However, most of the existing SKQ processing methods are either focused on Euclidean space or suffer from poor scalability. This paper addresses the problem of SKQ processing in road networks under wireless broadcast environments, and devises a novel air index called SKQAI, which combines a road network weighted quad-tree, several keyword quad-trees and a distance bound array, to facilitate SKQ processing in road networks. Based on SKQAI, efficient algorithms for processing Boolean Range, Top-k and Ranked SKQs are proposed. The proposed methods can efficiently prune irrelevant regions of the road network based on both road network distance and keyword information, and thus improve query processing efficiency significantly. Finally, simulation studies on two real road networks and two geo-textual datasets are conducted to demonstrate the effectiveness and efficiency of the proposed algorithms.

Interplay of Socioeconomic Status and Supermarket Distance Is Associated with Excess Obesity Risk: A UK Cross-Sectional Study.

U.S. policy initiatives have sought to improve health through attracting neighborhood supermarket investment. Little evidence exists to suggest that these policies will be effective, in particular where there are socioeconomic barriers to healthy eating. We measured the independent associations and combined interplay of supermarket access and socioeconomic status with obesity. Using data on 9702 UK adults, we employed adjusted regression analyses to estimate measured BMI (kg/m2), overweight (25 ≥ BMI < 30) and obesity (≥30), across participants’ highest educational attainment (three groups) and tertiles of street network distance (km) from home location to nearest supermarket. Jointly-classified models estimated combined associations of education and supermarket distance, and relative excess risk due to interaction (RERI). Participants farthest away from their nearest supermarket had higher odds of obesity (OR 1.33, 95% CI: 1.11, 1.58), relative to those living closest. Lower education was also associated with higher odds of obesity. Those least-educated and living farthest away had 3.39 (2.46–4.65) times the odds of being obese, compared to those highest-educated and living closest, with an excess obesity risk (RERI = 0.09); results were similar for overweight. Our results suggest that public health can be improved through planning better access to supermarkets, in combination with interventions to address socioeconomic barriers.

Comparing two distance measures in the spatial mapping of food deserts: The case of Petržalka, Slovakia

Abstract Over the last twenty years or so, researchers’ attention to the issue of food deserts has increased in the geographical literature. Accessibility to large-scale retail units is one of the essential and frequently-used indicators leading to the identification and mapping of food deserts. Numerous accessibility measures of various types are available for this purpose. Euclidean distance and street network distance rank among the most frequently-used approaches, although they may lead to slightly different results. The aim of this paper is to compare various approaches to the accessibility to food stores and to assess the differences in the results gained by these methods. Accessibility was measured for residential block centroids, with applications of various accessibility measures in a GIS environment. The results suggest a strong correspondence between Euclidean distance and a little more accurate street network distance approach, applied in the case of the urban environment of Bratislava-Petržalka, Slovakia.

Neighbourhood built environment characteristics associated with different types of physical activity in Canadian adults.

The aim of this study was to estimate the associations between neighbourhood built environment characteristics and transportation walking (TW), recreational walking (RW), and moderate-intensity (MPA) and vigorous-intensity physical activity (VPA) in adults independent of sociodemographic characteristics and residential self-selection (i.e. the reasons related to physical activity associated with a person's choice of neighbourhood). In 2007 and 2008, 4423 Calgary adults completed land-based telephone interviews capturing physical activity, sociodemographic characteristics and reasons for residential self-selection. Using spatial data, we estimated population density, proportion of green space, path/cycleway length, business density, bus stop density, city-managed tree density, sidewalk length, park type mix and recreational destination mix within a 1.6 km street network distance from the participants' geolocated residential postal code. Generalized linear models estimated the associations between neighbourhood built environment characteristics and weekly neighbourhood-based physical activity participation (≥ 10 minutes/week; odds ratios [ORs]) and, among those who reported participation, duration of activity (unstandardized beta coefficients [B]). The sample included more women (59.7%) than men (40.3%) and the mean (standard deviation) age was 47.1 (15.6) years. TW participation was associated with intersection (OR = 1.11; 95% CI: 1.03 to 1.20) and business (OR = 1.52; 1.29 to 1.78) density, and sidewalk length (OR = 1.19; 1.09 to 1.29), while TW minutes was associated with business (B = 19.24 minutes/week; 11.28 to 27.20) and tree (B = 6.51; 2.29 to 10.72 minutes/week) density, and recreational destination mix (B = -8.88 minutes/ week; -12.49 to -5.28). RW participation was associated with path/cycleway length (OR = 1.17; 1.05 to 1.31). MPA participation was associated with recreational destination mix (OR = 1.09; 1.01 to 1.17) and sidewalk length (OR = 1.10; 1.02 to 1.19); however, MPA minutes was negatively associated with population density (B = -8.65 minutes/ week; -15.32 to -1.98). VPA participation was associated with sidewalk length (OR = 1.11; 1.02 to 1.20), path/cycleway length (OR = 1.12; 1.02 to 1.24) and proportion of neighbourhood green space (OR = 0.89; 0.82 to 0.98). VPA minutes was associated with tree density (B = 7.28 minutes/week; 0.39 to 14.17). Some neighbourhood built environment characteristics appear important for supporting physical activity participation while others may be more supportive of increasing physical activity duration. Modifications that increase the density of utilitarian destinations and the quantity of available sidewalks in established neighbourhoods could increase overall levels of neighbourhood-based physical activity.

Do Poorer Areas Have Poorer Access to Services in Hong Kong? A Small-Area Analysis Based on Multiple Spatial Accessibility Indicators

Previous studies have yielded inconsistent findings regarding whether poorer areas have poorer access to health and social services. Using three indicators of service availability and accessibility, we investigated how the spatial accessibility of 28 types of services varied across quintiles of small-area poverty rates in Hong Kong. The results show that the patterns differed by the indicator used and the type of services examined. The service-to-population ratio tended to yield a “pro-rich pattern”, i.e. higher service availability in less poor neighborhoods, but the road-network distance indicator tended to yield a “pro-poor pattern”, i.e. a shorter distance by road to the nearest service in poorer neighborhoods; in contrast, the two-step floating catchment area index yielded patterns that were less consistent across different types of services. Consistency in the associations across the three accessibility indicators was found only for a few types of services, e.g. a “pro-poor pattern” for self-study rooms and a “pro-rich pattern” for swimming pools and tennis courts. As the three spatial accessibility indicators tended to generate different results, future research should include careful consideration of the choice of indicators and the context in which these indicators are utilized. Our analysis also indicates that the spatial distribution of services in Hong Kong does not always support the “deprivation amplification theory,” i.e. poorer areas are more deprived of resources; in Hong Kong, poorer areas had better, not poorer, access to certain services.

Examining the Social Context of Injection Drug Use: Social Proximity to Persons Who Inject Drugs Versus Geographic Proximity to Persons Who Inject Drugs.

In this analysis, we used social network and spatial data to examine associations between people's drug injection status and their social and/or spatial proximity to others who injected drugs. We recruited 503 rural Kentucky residents who used drugs to participate in the Social Networks among Appalachian People (SNAP) Study (2008-2010). Interviewer-administered surveys collected information on recent (past 6 months) sex, drug-use, and social-support network members (n = 897 ties). Using network simulations, we determined a threshold for the association between social proximity to others who injected drugs and recent injection status ("socially proximal" was defined by a shortest path ≤2). We defined "geographically proximal" as the median road-network distance between pairs of individuals who both injected drugs (≤7 miles (≤11.2 km)). Logistic regression was used to determine the independent and joint associations between the number of socially and/or geographically proximal injecting peers and a person's injection status. After adjustment, the odds of recent injection increased by 0.4% for each injecting peer who was geographically proximal but not socially proximal, 12% for each geographically and socially proximal injecting peer, and 22% for each injecting peer who was socially proximal but not geographically proximal. When implementing network-based interventions which promote cessation of injection drug use, investigators should consider collecting sociometric network data to examine whether the intervention diffuses through the network and whether there are additive or threshold effects.