Two-step Floating Catchment Area Research Articles

Assessing Rail Station Accessibility Based on Improved Two-Step Floating Catchment Area Method and Map Service API

Accessibility is an important index for evaluating the efficiency of rail stations. In view of the imbalance between the supply and demand of rail station settings and population distribution, this paper takes the Shijingshan District in Beijing as an example. Based on the Gaussian two-step floating catchment area method and Gaode map’s service interface, the accessibility of rail stations is simulated and analyzed in terms of both walking and riding. Combined with the calculation results, supply and demand relationship and trip time, the current characteristics and causes are analyzed, and the corresponding optimization suggestions are put forward. The main conclusions are as follows: (1) The accessibility distribution of rail stations in the Shijingshan District is relatively coordinated with the population distribution. The effectiveness of the accessibility assessment of rail stations can be further improved by improving the causal evaluation model with traditional calculation data; (2) The change of trip mode has a small impact on the accessibility of large stations, while small stations and areas with uneven station distribution can be improved by riding; (3) According to the K-value clustering method, the results of the two calculation methods are divided into five categories, and each category of demand units has different accessibility characteristics and causes; (4) Comprehensive accessibility is positively correlated with road density and population density.

Equity Study on Urban Park Accessibility Based on Improved 2SFCA Method in Zhengzhou, China

The distribution of urban parks is closely related to the opportunities of daily use by residents as well as the performance of the park system. The question as to whether parks are distributed equitably within cities is therefore becoming the focus of attention. However, only a few studies have explored a comprehensive and systematic procedure for urban park accessibility analysis and equity evaluation. In this study, by applying an improved two-step floating catchment area (2SFCA) method and K-means cluster analysis, based on the application of multi-source data, we provide insights into an equity study on park accessibility at the neighborhood scale and urban ring scale in the central urban area of Zhengzhou. These results suggest that the spatial access to parks in Zhengzhou is generally unevenly distributed among neighborhoods, and both the mean and standard deviation of accessibility show an increase from the center to the periphery. The cluster analysis reveals a set of four types of neighborhoods, including a high-supply medium-demand medium-accessibility type (HMM), a low-supply medium-demand low-accessibility type (LML), a high-supply low-demand high-accessibility type (HLH), and a medium-supply high-demand low-accessibility type (MHL), each with different characteristics and causes. The spatial distribution of the accessibility types exhibits both similarities and differences between the urban rings. The findings of this study could serve as a tool for identifying areas in which parks are underserved and the ways in which they differ from other areas, which can guide urban planning to address specific inequities.

Time-varying spatial accessibility of primary healthcare services based on spatiotemporal variations in demand, supply, and traffic conditions: A case study of Seoul, South Korea

IntroductionAlthough demand, supply, and traffic conditions are interdependent, scholars have considered them separately when measuring accessibility of healthcare services. Additionally, the spatiotemporal variations in these three factors are given relatively less attention in healthcare accessibility research, thereby misleading the policy decisions of healthcare planners. This study aims to examine the spatiotemporal variability of accessibility to primary healthcare services and identify areas with a spatial discrepancy between time-varying and static accessibility models in Seoul, South Korea. MethodsUsing the generalized two-step floating catchment area method, we measure time-varying spatial accessibility with de facto population from hourly collected mobile-based data, available primary healthcare facilities, and actual traffic conditions in Seoul. Additionally, the bivariate Local Moran's I allowed for the identification of areas with discrepancies between the two accessibility models. ResultsThe results show that a geographical pattern of time-varying accessibility significantly differs with that of static accessibility. Time-varying accessibility is lower in commercial and business areas and higher in residential areas, compared with static accessibility, which is higher in central Seoul. The result of the bivariate Local Moran's I analysis highlights that ignoring time variations of the three factors will result in overestimation in commercial areas and underestimation in residential areas. Based on the discrepancy between the two models, we identified the overestimated and underestimated areas. ConclusionWe suggest areas to which healthcare policy needs to pay more attention by identifying areas with spatial discrepancies between time-varying accessibility and static accessibility. Considering the time variations will provide a more realistic impression of spatial accessibility to primary healthcare.

Research on the Equity and Optimal Allocation of Basic Medical Services in Guangzhou in the Context of COVID-19.

Optimizing the allocation of basic medical services and ensuring their equity are necessary to improve the ability to respond to public health emergencies and promote health equity in the context of COVID-19. This study aims to analyze the equity of Guangzhou's basic medical service and identify areas where health resources are relatively scarce. The spatial distribution and patterns of basic medical services were analyzed using kernel density analysis and standard deviation ellipse. The equity was analyzed using the Gini coefficient and Lorenz curve in terms of population and geographical area, respectively. Considering the medical demand and supply sides, the Gaussian two-step floating catchment area method was used to analyze the accessibility to different levels of medical institutions. The kernel density analysis and standard deviation ellipse showed that the spatial distribution of medical and health resources in Guangzhou is unevenly distributed, and high-level hospitals and medical resources are mainly concentrated in the centrum. From the perspective of population, Guangzhou's medical equity is generally reasonable. The accessibility of medical institutions differs with different levels, and the tertiary medical institutions have the best accessibility, while the unclassified, primary, and secondary medical institutions generally have lower accessibility. The accessibility of districts in Guangzhou varies greatly. Areas in the center are most accessible to basic medical services, while accessibility in outskirt areas has gradually decreased. Conclusion: The quantity of per capita medical and health resources in Guangzhou, as evidenced by basic medical services, is sufficient, but the spatial distribution is unequal. The developed city center enjoys more adequate healthcare resources than the distant suburbs. Primary healthcare should be built, especially in distant suburbs, to strengthen basic medical service equity in Guangzhou.

Spatiotemporal Accessibility of COVID-19 Healthcare Facilities in Jakarta, Indonesia

During the first year of the COVID-19 pandemic in Jakarta, Indonesia, the government designated some hospitals as specific COVID-19 healthcare centers to meet demand and ensure accessibility. However, the policy demand evaluation was based on a purely spatial approach. Studies on accessibility to healthcare are widely available, but those that consider temporal as well as spatial dynamics are lacking. This study aims to analyze the spatiotemporal dynamics of healthcare accessibility against COVID-19 cases within the first year of the COVID-19 pandemic, and the overall pattern of spatiotemporal accessibility. A two-step floating catchment area (2SFCA) was used to analyze the accessibility of COVID-19 healthcare against the monthly data of the COVID-19 infected population, as the demand. Such a spatiotemporal approach to 2SFCA has never been used in previous studies. Furthermore, rather than the traditional buffer commonly used to define catchments, the 2SFCA in this study was improved with automated delineation based on the road network using ArcGIS Service Areas Analysis tools. The accessibility tends to follow the distance decay principle, which is relatively high in the city’s center and low in the outskirts. This contrasts with the city’s population distribution, which is higher on the outskirts and lower in the center. This research is a step toward optimizing the spatial distribution of hospital locations to correspond with the severity of the pandemic condition. One method to stop the transmission of disease during a pandemic that requires localizing the infected patient is to designate specific healthcare facilities to manage the sick individuals. ‘What-if’ scenarios may be used to experiment with the locations of these healthcare facilities, which are then assessed using the methodology described in this work to obtain the distribution that is most optimal.

The impact of traffic on equality of urban healthcare service accessibility: A case study in Wuhan, China

Accessibility to healthcare services strongly correlates with residents' health. As one of the objectives of sustainable cities, the social equality of access to healthcare plays a vital role in the rational allocation of healthcare facilities. However, limited attention has been paid to how the varying traffic conditions impact the equality of access to public service among places or demographic groups. Taking Wuhan, China, as the study area, this paper measured the hourly accessibility to healthcare by using two methods: Gaussian Two-Step Floating Catchment Area and Weighted Average Travel Time. Then, it investigated how traffic conditions affected the equality of healthcare services among places or demographic groups at different times. We found that traffic conditions change the accessibility by extending travel time and reducing the likelihood of obtaining healthcare services during peak hours, especially for suburban residents. Regarding equality evaluation, the impact of traffic variability on equality across places is much more significant than that on equality across demographic groups. The results highlight the effects of transport on the equal accessibility of healthcare and provide suggestions to minimise spatial and demographic disparities in healthcare services, meet the need of Sustainable Development Goals, and develop a more sustainable and inclusive society.

Assessing heat risk for residents of complex urban areas from an accessibility-based perspective

A heat risk assessment in complex urban areas is important to mitigate the impact of the urban heat island (UHI) and to accurately implement cooling measures. Previous studies have focused on a single 'heat source' or 'resident' oriented assessment method, with fewer assessments and lack of appropriate theoretical approaches that consider both the distribution of residents and heat core areas. This study combined a morphological spatial pattern analysis (MSPA) and a two-step floating catchment area (2SFCA) model to identify UHI patches and heat cores, assessed the accessibility of residents to heat core areas at the neighbourhood scale, and constructed a new framework for assessing the heat risk from an accessibility perspective. A case study of Shenzhen City indicated that the heat core area accounted for 5.5%, 7.8%, 10%, and 7.1% of the whole study area in February, May, August, and November, respectively. The relationship between the areas with a heat risk and UHI patches, and the dominant factors for the formation of different high-risk aggregations had a high spatial heterogeneity. The differences between the accessibility-based assessment results and conventional methods were also discussed, and the heat risk in conventional assessment methods was found to be in error. The accessibility-based heat risk assessment framework can accurately identify heat core areas and high heat risk areas, and provide effective planning guidance for mitigating the negative effects of UHI.

Measuring spatial accessibility and supply-demand deviation of urban green space: A mobile phone signaling data perspective.

The reasonable distribution of urban green space (UGS) is a topic that urban researchers have been exploring for a long time. Solving the imbalance between the supply and demand of UGS plays an important role in improving the health level of a city. This study examines the central urban area of Hefei as an example. We developed a modified Gaussian two-step floating catchment area method and used the path planning model of Gaode Map to evaluate the accessibility of UGS under different transportation modes and different time thresholds while integrating mobile phone signaling data. Additionally, a fine-scale analysis of the actual supply and demand relationship of UGS was conducted by integrating the accessibility evaluation results with the recreational situation of UGS to analyze the deviation of supply and demand to further discuss the spatial distribution equilibrium of UGS. The main conclusions are as follows. (1) The spatial distribution of UGSs in the central urban area of Hefei is uneven. Different time thresholds and different transportation modes have a significant impact on the UGS accessibility evaluation results. (2) With the increase in the time threshold or travel distance, the number of grids above the moderate accessibility level generally increases. The spatial distribution of the grids with moderate, high and highest accessibility level present different patterns of contiguous, clusters, and spots distribution. (3) After combining these results with the actual recreational situation of UGS, we found that the overall demand in the central urban area exceeds the supply at the 15-min threshold, while the overall supply exceeds the demand at the 30-min threshold. The grids with balanced supply and demand or more supply than demand have comprehensive parks with a moderate population density and strong road connectivity in the neighborhood. This study strengthens the data granularity and improves the accuracy of accessibility evaluation by integrating mobile phone signaling data with the path planning model of Gaode Map. Also, we evaluate the accessibility with multi-transport modes and different time thresholds, which can bring more practical guidance for optimizing the distribution of UGS.

Measuring equality in access to urban parks: A big data analysis from Chengdu.

Spatial equality of parks is a significant issue in environmental justice studies. In cities with high-density development and limited land resources, this study uses a supply-demand adjusted two-step floating catchment area model (2SFCA), paying attention to residents' subjective preferences and psychological accessibility. It assesses equality of access to urban parks from two dimensions: spatial equality and quantitative equality at a fine scale of 100 × 100 m grid resolution. The spatial equality of urban parks in Chengdu is measured under different transportation modes (walking, cycling, and driving) based on multi-source geospatial big data and machine learning approaches. The results show: (1) There were significant differences in the spatial distribution of park accessibility under different modes of transportation. The spatial distribution under walking was significantly influenced by the park itself, while the distribution of rivers significantly influenced the spatial distribution under cycling and driving; (2) Accessibility to urban parks was almost universally equal in terms of driving, relatively equal in terms of cycling, and seriously unequal in terms of walking; (3) Spatial local autocorrelation analysis shows that park accessibility tended to be significantly clustered, with little spatial variation; and (4) The supply and demand of urban parks were relatively equal. The results can help urban planners to formulate effective strategies to alleviate spatial inequality more reasonably and precisely. The applied research methods can further improve the system of scientific evaluation from a new perspective.

PM2SFCA: Spatial Access to Urban Parks, Based on Park Perceptions and Multi-Travel Modes. A Case Study in Beijing

Assessing park accessibility plays an essential role in providing rational recreational services for residents in a city. The perceptions and comments of residents are also important nonspatial factors for accessibility. However, there are few accessibility studies that are combined with public perceptions. Addressing this deficit, this study proposes a perception-based, multi-travel mode, two-step floating catchment area (PM2SFCA) method to calculate park accessibility. First, we quantified the selection probability of residents to parks by integrating the Huff model and the people’s perceptions towards parks. Next, under four travel modes (walking, biking, driving and public transport), we combined the Huff model and the two-step floating catchment area method to compute park accessibility. Furthermore, the Gini coefficient and the Pearson correlation coefficient were used to illustrate the proposed method compared with the traditional E2SFCA method. Based on the above, taking the area of Beijing within the Fifth Ring Road as a study area, this paper facilitated the accessibility computation. The results indicated that the spatial distribution patterns of accessibility differed greatly under the four travel modes. Even under the same travel mode, there was an uneven accessibility distribution. Areas with high accessibility were mainly concentrated in the north, and some marginal areas also presented higher accessibility to parks. The comparative analysis results suggest that our proposed method for accessibility measurements alleviates the underestimation and overestimation of accessibility values obtained by a traditional method such as the center and edge of the study area. The research explores a new research perspective for measuring park accessibility. Furthermore, this study offers better guidance for policymakers trying to optimize park spatial distribution issues.

Disparities in spatial accessibility to public dental services relative to estimated need for oral health care among refugee populations in Victoria.

To examine the spatial accessibility to public dental services (PDS) relative to the estimated oral health needs of refugee populations within the state of Victoria, Australia. The study employed enhanced two-step floating catchment area method to measure spatial accessibility to PDS by driving and public transit modes at statistical area level 2 (SA2). Principal component analysis of select census-derived socioeconomic variables specific to the refugee population was conducted to derive an area-based indicator of refugee oral health needs, also at SA2 level. Individual indices were then developed for each of these components using standardized z-scores. Finally, an integrated need-accessibility index was developed to identify low-accessibility areas associated with high needs. The results show clear contrast in spatial accessibility to PDS for the refugee populations between metropolitan and rural areas as well as between driving and public transit modes. There are critical limitations in accessibility for refugees living in the rural areas and those dependent on public transit mode for travel. Also, there is evident disparity between the estimated oral health needs of refugees in metropolitan and rural areas. Overall, approximately 29% of all SA2s with refugee population are in the 'High' needs category, which comprise 19.8% of the total Victorian refugee population. Integrating accessibility and oral health needs measures revealed that about 30% and 18% of refugee population are identified as under-serviced, when considering driving and public transit modes respectively. The findings provide implications for researchers and policy makers to address the inequalities in access to PDS among the refugee population in Victoria. The methodology outlined in this study provides a complementary approach in planning oral health service provision in the absence of population level data at a small-area scale on access to dental services or need for oral health care.

An Improved Multi-Mode Two-Step Floating Catchment Area Method for Measuring Accessibility of Urban Park in Tianjin, China

Parks, as a major infrastructure that provide public service for urban residents, play a vital role in promoting urban livability and public health. Under the framework of spatial equity, more sophisticated accessibility methods were used on measuring urban park accessibility such as multi-mode 2SFCA. However, the accessibility of residential areas near parks was seriously underestimated by using the multi-mode 2SFCA method. Thus, this study aimed to propose an improved multi-mode 2SFCA method to measure urban park accessibility with a more appropriate approach, by taking residential areas of Tianjin central city as the spatial unit. The results indicate that all residential areas can obtain urban park accessibility, but the spatial distribution of urban park accessibility is heterogeneous. The numerical value of urban park accessibility decreases as the travel time from residential areas to urban parks increases; it is shown that the proposed method can provide a more realistic evaluation compared to the traditional multi-mode 2SFCA method. This study provides a comprehensive and realistic insight into acquainting with urban park accessibility and helps urban planners formulate effective policies and strategies to ease spatial imbalance.

Spatial supply-demand balance of green space in the context of urban waterlogging hazards and population agglomeration

Urban green space (UGS) contributes significantly to urban settlements with respect to frequent rainstorm events and population agglomeration issues, but there is limited understanding of the spatial match between green space supply and social demand. This study established an integrated evaluation framework relating to the supply–demand balance of UGS. In a case study of Beijing, the urban waterlogging risk was simulated with an ICM model, and specific demand criteria of waterlogging hazards and population needs were considered. The street-scale supply–demand balance of demands for existing and future UGS was then quantified with the two-step floating catchment area method. Comparison of the street-level balance in large rainstorms and populated areas identified the key locations where the green space supply should be strengthened in Beijing. This study may provide an integrated evaluation of green space accessibility and a solid foundation for refined urban land-use planning strategies.

An Improved Two-Step Floating Catchment Area (2SFCA) Method for Measuring Spatial Accessibility to Elderly Care Facilities in Xi'an, China.

With the continuous aging of society, the demand among elderly citizens for care facilities is increasing. The accessibility of elderly care facilities is a significant indicator for evaluating whether the layout of urban elderly care facilities is reasonable, and research on the spatial accessibility of related facilities has become an important academic issue in recent years. In this paper, based on the lack of accurate measurement in calculating the spatial accessibility of existing elderly care facilities, we improve the mathematical model based on the two-step floating catchment area method (2SFCA) and introduce the probability function of the elderly population’s choice, taking into account the influence of institutional capacity and service quality. In terms of the catchment radius, the calculation accuracy is improved by using the shortest distance along the route combined with the real road network instead of choosing the Euclidean distance. In addition, specific travel thresholds are set for the travel characteristics of the elderly. An evaluation model of the accessibility of urban elderly care facilities is constructed with the help of ArcGIS software to evaluate and analyze the accessibility of the current layout of urban elderly care facilities in Xi’an, China. The results show that the improved 2SFCA model is more effective in evaluating the spatial accessibility of elderly care facilities and has higher accuracy than the previous calculation model, which provides a methodological basis and academic reference for the specific planning of urban elderly care facilities.

A layout optimization approach to urban park green spaces based on accessibility evaluation: a case study of the central area in Wuxi city

ABSTRACT Planning urban park green spaces equitably and effectively is a central concern for maintaining a sustainable city and enhancing the quality of life of urban dwellers. In this case study of Wuxi city, facilitated by multisource big data, a new approach for optimizing the urban park green space distribution was explored. The improved two-step floating catchment area method was employed in combination with the network analyst in ArcGIS, the real entrances of urban park green spaces as search centres, multiple radii, and the distance decay function. The districts with low accessibility to urban park green spaces were mapped accurately as the main zones for equity promotion. Then, the key plots for the layout optimization of urban park green spaces at different scales were identified based on the location-allocation model. The results indicated a significant spatial gradient pattern of the accessibility index and a lower degree of spatial fitting between the service capacity of urban park green spaces and user demands in the old town. Additionally, operable location selection strategies prioritizing the urban natural environment and integrating the urban inventory space for urban park green space layout to improve the accessibility level were tentatively proposed. Finally, for the factors influencing accessibility, the park’s size and conditions, transportation network, and the social attribute of urban residents were further discussed. This study could help city managers and planners conduct the layout optimization of urban park green spaces more effectively with the aim of promoting an environmentally equitable and sustainable life.

Spatial and Nonspatial Factors Associated with Access to Medication for Opioid Use Disorder among Pregnant Women in Massachusetts

Introduction In Massachusetts, one-third of pregnant women with opioid use disorder (OUD) do not receive medications for OUD (MOUD), such as buprenorphine and methadone. Research has demonstrated that broadly, access to medications differs by location and by socioeconomic and geographic characteristics of communities, but a comprehensive understanding at the micro-level is lacking. This study aims to identify and characterize access to MOUD treatment among pregnant women in Massachusetts. Methods We used enhanced two-step floating catchment area analyses, which incorporated supply and demand measures, as well as local drive-time, to determine spatial accessibility to MOUD. We used four publicly available data sources to calculate geographic accessibility to MOUD. We then merged the resulting accessibility indices with data from the American Community Survey to statistically analyze ZIP Code Tabulation Area (ZCTA) characteristics that were associated with geographic accessibility to MOUD among the study population. Results We calculated access to 258 opioid (methadone and/or buprenorphine) treatment programs and 2,585 buprenorphine-waivered prescribers among 74,969 pregnant women during the period 2016–2020 in 448 ZCTAs (N = 537 ZCTAs). ZCTAs with lower accessibility to both types of MOUD were concentrated in Western Massachusetts. Central Massachusetts had poor accessibility to buprenorphine providers. Accessibility was greater in ZCTAs that were nonmetropolitan, that had higher minority status and langauge vulnerability, and that had less extreme concentration of privilege. Conclusions There is a need to improve MOUD access overall, and to enhance access to both types of medications, so pregnant women can choose the one that works best for them.

Post-earthquake health care service accessibility assessment framework and its application in a medium-sized city

In the aftermath of an earthquake, damage to buildings and transportation networks severely affects post-earthquake emergency rescue and medical health care services. This paper presents a quantitative framework considers seismic damage to buildings and transportation networks, post-earthquake available numbers of patient beds and medical staff to evaluate post-earthquake health care service accessibility. The modified two-step floating catchment area method and seismic fragility analysis are integrated into the proposed framework. Spatial distributions of demand point, hospital, and transportation network data are used to evaluate health care service accessibility. The accessibility results for a medium-sized city under normal conditions and post-earthquake conditions are analyzed as a case study. Demand points that lack access to health care service can be clearly delineating from the findings, indicating that large earthquakes will dramatically impact people’ normal health care service accessibility. The results of this work may provide a workable basis for planners and policy makers to pragmatically select health care facility sites.

Research on the Equity of Urban Green Park Space Layout Based on Ga2SFCA Optimization Method—Taking the Core Area of Beijing as an Example

(1) Background: The issue of equity in the layout of urban green park spaces is an essential dimension of urban public resource allocation. (2) Objective: To analyze the equity of the distribution of parkland in the core area of Beijing from a quantitative and spatial perspective. By measuring both vehicular and pedestrian transport modes, the study identifies areas with low levels of green space provision and provides strategies for optimization. It is hoped that this study can provide a basis for future green space construction in the core area of Beijing. (3) Methods: In this paper, the Gauss Two-step Floating Catchment Area Method (Ga2SFCA) is used to study the green park space layout in the core area of Beijing. The two modes of 30min-walk and 10min-car-journey were used to measure the fair values of the residential unit scale, the street district scale, and the overall scale, respectively. (4) Results: The study results show that the fair values based on the 30-min walk and the 10-min car journey differ significantly. For the 30-min walk-based travel mode, the proportion of fair (Class IV) and fairer (Class V) areas is approximately 20%, while for the 10 min car-based travel mode, the corresponding class is over 90%. (5) Conclusions: The overall equity of urban parkland in Beijing core area is better for car-based travel modes, while for walking modes, the supply is still insufficient, and the distribution of parkland is polarized.

Challenging terrains: socio-spatial analysis of Primary Health Care Access Disparities in West Virginia.

Challenging terrains: socio-spatial analysis of Primary Health Care Access Disparities in West Virginia.

Accessibility calculation and equality evaluation of medical facilities for COVID-19 pandemic treatment: A case study of the Wuhan metropolitan development zone.

Medical facility equality is a critical metric for determining equal access to medical care. Their spatial distribution is important for effective pandemic treatment and daily prevention in cities. This paper used the Kernel Density Two-Step Floating Catchment Area (KD2SFCA) and shortest distance methods to calculate the accessibility of designated COVID-19 Fangcang hospitals and fever clinics in the Wuhan Metropolitan Development Zone. Their equality was evaluated by the Gini coefficient and Lorentz curve. Several results were obtained: (1) The facilities’ accessibility declines radial from the central to peripheral areas. (2) Most of the demand points in the study area can reach the medical facilities for COVID-19 pandemic treatment within 60 minutes. (3) For the spatial distribution of these facilities, the equality evaluated for different time thresholds differed significantly, with long time thresholds having better equality than for short time thresholds. (4) While the distances distribution of fever clinics is balanced, the equality gap in various areas remains enormous when considering population distribution. Suggestions for optimizing the spatial distribution of pandemic treatment medical facilities in Wuhan are proposed, and which will serve as references for the planning of Wuhan’s pandemic medical facilities in the future.