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Recently, people are increasingly interested in understanding broader and longer-term individual activity-travel behaviors across days or even weeks. However, the relationship of individual daily activity-travel behaviors over multi-days only remains partially revealed, especially between workdays and day-offs. Thus, we develop an effective framework to extract individual daily activity-travel patterns from massive mobile phone network data on basis of location activity motifs (LAMs), which are beneficial to combining the locations, activities, and trips in daily activity-travel behaviors. We then discover that the modified number of LAMs over time conforms well to the classic exploration and preferential return (EPR) model after excluding the influence of the number of trips, which reproduces the human activity-travel behavior characteristics on daily scale and indicates that the complex relationship of LAMs exists between workdays and day-offs. Furthermore, we emphasize three categories of correlation patterns while the relationship of LAMs between workdays and day-offs is instantiated using association rules mining algorithm. Ultimately, the regular individual differences and obvious spatial heterogeneity reveal the formation mechanism of correlation patterns. These empirical results contribute to develop different but related transportation strategies between workdays and day-offs by understanding individual daily activity-travel behaviors.
Qiangqiang Xiong; Yaolin Liu; Peng Xie; Yiheng Wang; Yanfang Liu. Revealing correlation patterns of individual location activity motifs between workdays and day-offs using massive mobile phone data. Computers, Environment and Urban Systems 2021, 89, 101682 .
AMA StyleQiangqiang Xiong, Yaolin Liu, Peng Xie, Yiheng Wang, Yanfang Liu. Revealing correlation patterns of individual location activity motifs between workdays and day-offs using massive mobile phone data. Computers, Environment and Urban Systems. 2021; 89 ():101682.
Chicago/Turabian StyleQiangqiang Xiong; Yaolin Liu; Peng Xie; Yiheng Wang; Yanfang Liu. 2021. "Revealing correlation patterns of individual location activity motifs between workdays and day-offs using massive mobile phone data." Computers, Environment and Urban Systems 89, no. : 101682.
Limited studies focus on educational equity from the spatial accessibility perspective. This study combines survey data and big data and proposes a multi-mode Huff two-step floating catchment area (MMH2SFCA) method to calculate accessibility while considering multiple travel modes and school attractiveness. This method can also calculate education quality by extending the accessibility in each community. Results show that our proposed method can reliably identify the accessibility differences of schools across communities. The case study indicates an inequitable distribution of educational accessibility and quality. The communities with high accessibility are concentrated in the urban center and exurban zones surrounding schools, whereas high-quality areas are mainly concentrated in the urban center. Correlation analysis suggests that the educational quality of communities with high accessibility is not always high. The findings of this study can provide improvement for accessibility measurements and help explore a new research perspective for educational equity research.
Yiheng Wang; Yaolin Liu; Lijun Xing; Ziyi Zhang. An Improved Accessibility-Based Model to Evaluate Educational Equity: A Case Study in the City of Wuhan. ISPRS International Journal of Geo-Information 2021, 10, 458 .
AMA StyleYiheng Wang, Yaolin Liu, Lijun Xing, Ziyi Zhang. An Improved Accessibility-Based Model to Evaluate Educational Equity: A Case Study in the City of Wuhan. ISPRS International Journal of Geo-Information. 2021; 10 (7):458.
Chicago/Turabian StyleYiheng Wang; Yaolin Liu; Lijun Xing; Ziyi Zhang. 2021. "An Improved Accessibility-Based Model to Evaluate Educational Equity: A Case Study in the City of Wuhan." ISPRS International Journal of Geo-Information 10, no. 7: 458.
Cropland protection strategies have provided a strong contribution to limit cropland transformation worldwide. However, it negatively affects ecological land (e.g., forest, grassland, and wetland). Identifying a win-win approach for cropland protection and ecological conservation is important. Land use optimization plays a vital role in solving conflicts among land uses. Thus, in this research, taking China (mainland) as the study area, we optimized the spatial distribution of urban land and cropland to balance the requirement of cropland protection strategies and their negative effects on ecological land according to the spatial heterogeneity of land agricultural production capacity by using the LAND System Cellular Automata model for Potential Effects (LANDSCAPE). Specifically, we developed three optimization scenarios from compensational, occupancy, and occupancy and compensational sectors. We also developed one non-optimization scenario to remain comparable. Results show that compared with the non-optimization scenario, the reduced loss of ecological land in compensational, occupancy, and occupancy and compensational optimization scenario is 7180, 247, and 7277 km2, respectively. Our research indicates that we should prioritize the quality of compensated cropland when developing cropland protection strategies and planning, considering the low efficiency of the occupancy optimization and the cost of policymaking and implementing.
Liye Wang; Weiwei Zheng; Lanping Tang; Siyu Zhang; Yaolin Liu; Xinli Ke. Spatial optimization of urban land and cropland based on land production capacity to balance cropland protection and ecological conservation. Journal of Environmental Management 2021, 285, 112054 .
AMA StyleLiye Wang, Weiwei Zheng, Lanping Tang, Siyu Zhang, Yaolin Liu, Xinli Ke. Spatial optimization of urban land and cropland based on land production capacity to balance cropland protection and ecological conservation. Journal of Environmental Management. 2021; 285 ():112054.
Chicago/Turabian StyleLiye Wang; Weiwei Zheng; Lanping Tang; Siyu Zhang; Yaolin Liu; Xinli Ke. 2021. "Spatial optimization of urban land and cropland based on land production capacity to balance cropland protection and ecological conservation." Journal of Environmental Management 285, no. : 112054.
Visible and near-infrared reflectance (VIS-NIR) spectroscopy is widely applied to estimate soil organic carbon (SOC). Intense and diverse human activities increase the heterogeneity in the relationships between SOC and VIS-NIR spectra in anthropogenic soil. This fact results in poor performance of SOC estimation models. To improve model accuracy and parsimony, we investigated the performance of two variable selection algorithms, namely competitive adaptive reweighted sampling (CARS) and random frog (RF), coupled with five spectral pretreatments. A total of 108 samples were collected from Jianghan Plain, China, with the SOC content and VIS-NIR spectra measured in the laboratory. Results showed that both CARS and RF coupled with partial least squares regression (PLSR) outperformed PLSR alone in terms of higher model accuracy and less spectral variables. It revealed that spectral variable selection could identify important spectral variables that account for the relationships between SOC and VIS-NIR spectra, thereby improving the accuracy and parsimony of PLSR models in anthropogenic soil. Our findings are of significant practical value to the SOC estimation in anthropogenic soil by VIS-NIR spectroscopy.
Lu Xu; Yongsheng Hong; Yu Wei; Long Guo; Tiezhu Shi; Yi Liu; Qinghu Jiang; Teng Fei; Yaolin Liu; Abdul Mouazen; Yiyun Chen. Estimation of Organic Carbon in Anthropogenic Soil by VIS-NIR Spectroscopy: Effect of Variable Selection. Remote Sensing 2020, 12, 3394 .
AMA StyleLu Xu, Yongsheng Hong, Yu Wei, Long Guo, Tiezhu Shi, Yi Liu, Qinghu Jiang, Teng Fei, Yaolin Liu, Abdul Mouazen, Yiyun Chen. Estimation of Organic Carbon in Anthropogenic Soil by VIS-NIR Spectroscopy: Effect of Variable Selection. Remote Sensing. 2020; 12 (20):3394.
Chicago/Turabian StyleLu Xu; Yongsheng Hong; Yu Wei; Long Guo; Tiezhu Shi; Yi Liu; Qinghu Jiang; Teng Fei; Yaolin Liu; Abdul Mouazen; Yiyun Chen. 2020. "Estimation of Organic Carbon in Anthropogenic Soil by VIS-NIR Spectroscopy: Effect of Variable Selection." Remote Sensing 12, no. 20: 3394.
Livability is one of the major guiding principles for urban planning and policymaking, of which the definition and evaluation have become the crucial research topic. As the progress in socioeconomic development accelerates, the microscale living conditions require more urgent attention. However, few researchers have addressed the assessment of urban livability at a finer spatial scale such as the community scale. Thus, this article aims to evaluate the urban environmental quality at the community level given the residential community as the basic unit of urban living areas. We select eighteen objective indicators from five dimensions to establish an objective indicator system. Taking the preferences of different age groups into account, a comprehensive evaluation framework for the livability of communities combining both subjective perceptions and objective indicator is constructed. Then, it is applied to evaluate the livability of 1,394 residential communities in Ningbo City. There are three significant results from the study. First, different age groups have diverse preferences of demands to the livability of an urban community. The indicators they valued most concentrated in the following two dimensions: the convenience of transportation and the completeness of supporting facilities. Second, there exists significant heterogeneity in the livability of communities among districts. Third, the livability of communities shows a decreasing spatial pattern from the city center to the surroundings. These empirical results can be advantageous to urban planning departments and other relevant stakeholders.
Xiaojin Liang; Yaolin Liu; Tianqi Qiu. Livability Assessment of Urban Communities considering the Preferences of Different Age Groups. Complexity 2020, 2020, 1 -15.
AMA StyleXiaojin Liang, Yaolin Liu, Tianqi Qiu. Livability Assessment of Urban Communities considering the Preferences of Different Age Groups. Complexity. 2020; 2020 ():1-15.
Chicago/Turabian StyleXiaojin Liang; Yaolin Liu; Tianqi Qiu. 2020. "Livability Assessment of Urban Communities considering the Preferences of Different Age Groups." Complexity 2020, no. : 1-15.
The accurate mapping of farmland soil organic carbon density (SOCD) is crucial for evaluating carbon (C) sequestration potential and forecasting climate change. Natural factors such as soil types and topographical factors are important variables in mapping soil properties. Moreover, cropping systems are important components of agricultural activities and are significantly correlated with soil properties. Therefore, integrating cropping systems and natural factors can improve the accuracy of mapping farmland SOCD. This study aimed to obtain and incorporate cropping system information in mapping SOCD in plains by combining normalized difference vegetation index (NDVI) time-series data and the regression Kriging (RK) method. We collected 230 topsoil samples in Jianghan Plain, China and (i) obtained the spatial patterns of crops in summer and winter using NDVI time-series data derived from HJ-1A/1B satellite images, (ii) investigated the differences in SOCD under different cropping systems, and (iii) evaluated the performance of the RK_CS model in integrating cropping systems and natural factors into mapping SOCD. ANOVA results showed significant differences in SOCD under different cropping systems. Specifically, the SOCD of single rice was higher than that of rice–wheat rotation and dry crops. Meanwhile, the regression results showed that SOCD was affected by natural factors and cropping system, with the latter playing a major role. The integration of soil types, slope and cropping systems explained approximately 26.3% of the variation in SOCD. Model validation results confirmed the effectiveness of the RK_CS model. The findings reveal single cropping rice sequences more C than other cropping systems. Cropping system is an important environmental variable in improving mapping farmland SOCD in plains.
Zihao Wu; Yaolin Liu; Yiran Han; Jianai Zhou; Jiamin Liu; Jingan Wu. Mapping farmland soil organic carbon density in plains with combined cropping system extracted from NDVI time-series data. Science of The Total Environment 2020, 754, 142120 .
AMA StyleZihao Wu, Yaolin Liu, Yiran Han, Jianai Zhou, Jiamin Liu, Jingan Wu. Mapping farmland soil organic carbon density in plains with combined cropping system extracted from NDVI time-series data. Science of The Total Environment. 2020; 754 ():142120.
Chicago/Turabian StyleZihao Wu; Yaolin Liu; Yiran Han; Jianai Zhou; Jiamin Liu; Jingan Wu. 2020. "Mapping farmland soil organic carbon density in plains with combined cropping system extracted from NDVI time-series data." Science of The Total Environment 754, no. : 142120.
Urban agglomeration is the engine of national development and regional prosperity. Although extensive work has investigated issues related to this new form of spatial governance, few studies have directly illustrated the spatial integration of urban agglomeration and its relationship with industrial development. This paper employs nighttime light data and industrial enterprise datasets to investigate the spatial integration and industrial development in the Yangtze River Economic Belt (YREB) of China for 1995–2015. We here illustrate the significant relationship between the spatial integration of urban agglomerations and the characteristics of industrial development. In the process of spatial integration, urban form, intercity relation and their evolution show clear regional differences. Because of the differences in socio-economic and geographical characteristics, urban systems are more advanced and closely related in developed areas. A significant negative (positive) spatial correlation between industrial specialization (diversification) and urban form is supported by using bivariate Moran's I, and spatial clustering patterns are clearly different across the three urban agglomerations. A panel regression reveals that intercity relations are significantly associated with the characteristics of industrial development. Higher levels of industrial diversification and competition are associated with weaker intercity relations, while industrial structures similarities are reversed. These findings could be used to formulate reasonable policies and plans and to support future regional spatial integration and coordinated development.
Yaolin Liu; Xianghui Zhang; Xingyu Pan; Xiuxin Ma; Mingyang Tang. The spatial integration and coordinated industrial development of urban agglomerations in the Yangtze River Economic Belt, China. Cities 2020, 104, 102801 .
AMA StyleYaolin Liu, Xianghui Zhang, Xingyu Pan, Xiuxin Ma, Mingyang Tang. The spatial integration and coordinated industrial development of urban agglomerations in the Yangtze River Economic Belt, China. Cities. 2020; 104 ():102801.
Chicago/Turabian StyleYaolin Liu; Xianghui Zhang; Xingyu Pan; Xiuxin Ma; Mingyang Tang. 2020. "The spatial integration and coordinated industrial development of urban agglomerations in the Yangtze River Economic Belt, China." Cities 104, no. : 102801.
The correct urban building layout is an important influencing factor in urban ventilation, and the heat island effect has become an important factor affecting the quality of urban life. Optimization of the urban building layout can play a role in mitigating the heat island effect. The traditional ventilation corridor analysis method, based on a least-cost path analysis, can only generate a few main ventilation corridors. It is difficult to obtain global ventilation results covering the whole study area using this method of analysis. On the basis of urban morphology and a least-cost path analysis, this study proposes a “least cumulative ventilation cost” method for analyzing urban ventilation. Taking Wuhan downtown as a research area, the urban ventilation environment under different wind directions and seasons was analyzed. This method can effectively express the ventilation conditions throughout the whole study area and can simultaneously express the quality of the generated corridors effectively. The results show that Wuhan has three levels of ventilation corridor. Moreover, the ventilation conditions in Wuchang (Wuchang, Qingshan, and Hongshan) are better than those in Hankou (Qiaokou, Jianghan, and Jiang’an).
Peng Xie; Dianfeng Liu; Yanfang Liu; Yaolin Liu. A Least Cumulative Ventilation Cost Method for Urban Ventilation Environment Analysis. Complexity 2020, 2020, 1 -13.
AMA StylePeng Xie, Dianfeng Liu, Yanfang Liu, Yaolin Liu. A Least Cumulative Ventilation Cost Method for Urban Ventilation Environment Analysis. Complexity. 2020; 2020 ():1-13.
Chicago/Turabian StylePeng Xie; Dianfeng Liu; Yanfang Liu; Yaolin Liu. 2020. "A Least Cumulative Ventilation Cost Method for Urban Ventilation Environment Analysis." Complexity 2020, no. : 1-13.
With the continuous development of global urbanization, the urban heat island effect has increasingly become one of the important factors that reduces the quality of urban life. Among the many factors affecting the formation of urban heat islands, urban canopy ventilation is considered to have great potential for improving urban heat islands. Based on the traditional numerical simulation of ventilation corridor analysis, this paper proposes a new approach for ventilation corridor recognition based on circuit theory. The connotations of resistance, current, and voltage in the simulation of urban ventilation environment were explained separately. Taking Wuhan as the research area, local three-dimensional building data were used as the data source, and a simulation experiment of the urban ventilation environment with different winds was carried out on the 100-m grid scale. Unlike the method based on the least-cost path analysis by which only a few main ventilation corridors can be generated, the results of the method proposed in this paper cover all grid cells in the study area. The simulation results were represented by probabilistic values, which can effectively reflect the ventilation corridor and ventilation barriers. In addition to identifying the ventilation corridors, the tuyeres were also well identified.
Peng Xie; Jun Yang; Huiying Wang; Yanfang Liu; Yaolin Liu. A New method of simulating urban ventilation corridors using circuit theory. Sustainable Cities and Society 2020, 59, 102162 .
AMA StylePeng Xie, Jun Yang, Huiying Wang, Yanfang Liu, Yaolin Liu. A New method of simulating urban ventilation corridors using circuit theory. Sustainable Cities and Society. 2020; 59 ():102162.
Chicago/Turabian StylePeng Xie; Jun Yang; Huiying Wang; Yanfang Liu; Yaolin Liu. 2020. "A New method of simulating urban ventilation corridors using circuit theory." Sustainable Cities and Society 59, no. : 102162.
Ecosystem services (ESs) are facing challenges from urbanization processes globally. Exploring how ESs respond to urbanization provides valuable information for ecological protection and urban landscape planning. Previous studies mainly focused on the global and single-scaled responses of ESs but ignored the spatially heterogenous and scale-dependent characteristics of these responses. This study chose Wuhan City in China as the study area to explore the spatially varying and scale-dependent responses of ESs, i.e., grain productivity, carbon sequestration, biodiversity potential and erosion prevention, to urbanization using geographically weighted regression (GWR). The results showed that the responses of ESs were spatially nonstationary evidenced by a set of local parameter estimates in GWR models, and scale-dependent indicated by two kinds of scale effects: effect of different bandwidths and effect of grid scales. The stationary index of GWR declined rapidly as the bandwidth increased until reaching to a distance threshold. Moreover, GWR outperformed ordinary least square at both grid scales (i.e., 5 km and 10 km scales) and behaved better at finer scale. The spatially non-stationary and scale-dependent responses of ESs to urbanization are expected to provide beneficial guidance for ecologically friendly urban planning.
Yan Zhang; Yanfang Liu; Jiawei Pan; Yang Zhang; Dianfeng Liu; Huiting Chen; Junqing Wei; Ziyi Zhang; Yaolin Liu. Exploring Spatially Non-Stationary and Scale-Dependent Responses of Ecosystem Services to Urbanization in Wuhan, China. International Journal of Environmental Research and Public Health 2020, 17, 2989 .
AMA StyleYan Zhang, Yanfang Liu, Jiawei Pan, Yang Zhang, Dianfeng Liu, Huiting Chen, Junqing Wei, Ziyi Zhang, Yaolin Liu. Exploring Spatially Non-Stationary and Scale-Dependent Responses of Ecosystem Services to Urbanization in Wuhan, China. International Journal of Environmental Research and Public Health. 2020; 17 (9):2989.
Chicago/Turabian StyleYan Zhang; Yanfang Liu; Jiawei Pan; Yang Zhang; Dianfeng Liu; Huiting Chen; Junqing Wei; Ziyi Zhang; Yaolin Liu. 2020. "Exploring Spatially Non-Stationary and Scale-Dependent Responses of Ecosystem Services to Urbanization in Wuhan, China." International Journal of Environmental Research and Public Health 17, no. 9: 2989.
Cropland and its production toward sustainable pattern play an indispensable role in supporting a virtuous circle of economy–society–ecology and achieving the Sustainable Development Goals. Taking Cheng–Yu Urban Agglomeration, China as a study area, this study developed an evaluation framework to conceptualize cropland use into the economy–society–ecology context with an improved Ecological Footprint analysis and triangle model. Stepwise linear regression model and GeoDetector were then introduced to identify the spatiotemporal driving factors and mechanism of cropland use sustainability. Results reveal the following. (1) From 2003 to 2017, cropland use sustainability temporally presents a downward trend of inverse S–shape fluctuation with sustainability status transitioning from weak unsustainability to strong unsustainability at the turning point in 2008. Cropland use sustainability spatially presents the spatial correlation with a significant agglomeration effect. The spatial distribution of sustainability status in the east is higher than that in the west. (2) Factors of cropland use sustainability, including cropland areas, sown area of farm crops, pesticides consumption, urbanization rate, city impact–force and runoff depth interactionally form the multi–dimensional driving mechanism. (3) Sixteen cities across the province boundaries can be grouped into three zones, namely, intensive utilization zone, protection priority zone and ecological restoration zone with the targeted and differentiated development paths accordingly. These findings can contribute to simply understanding and visualizing the status and trends of cropland use sustainability and decision–making for national–level urban agglomeration construction.
Chao Cheng; Yaolin Liu; Yanfang Liu; Renfei Yang; Yongsheng Hong; Yanchi Lu; Jiawei Pan; Yiyun Chen. Cropland use sustainability in Cheng–Yu Urban Agglomeration, China: Evaluation framework, driving factors and development paths. Journal of Cleaner Production 2020, 256, 120692 .
AMA StyleChao Cheng, Yaolin Liu, Yanfang Liu, Renfei Yang, Yongsheng Hong, Yanchi Lu, Jiawei Pan, Yiyun Chen. Cropland use sustainability in Cheng–Yu Urban Agglomeration, China: Evaluation framework, driving factors and development paths. Journal of Cleaner Production. 2020; 256 ():120692.
Chicago/Turabian StyleChao Cheng; Yaolin Liu; Yanfang Liu; Renfei Yang; Yongsheng Hong; Yanchi Lu; Jiawei Pan; Yiyun Chen. 2020. "Cropland use sustainability in Cheng–Yu Urban Agglomeration, China: Evaluation framework, driving factors and development paths." Journal of Cleaner Production 256, no. : 120692.
Determining the factors that control the spatial variation of heavy metals in suburban soil is important in identifying and preventing pollution sources. Soil intrinsic factors combined with environmental variables can effectively explain the spatial distribution of heavy metals. Compared with classical statistical methods, such as multiple linear regression (MLR) models, spatial regression models that can cope with the spatial dependence of heavy metals have greater potential in establishing an accurate relationship between influencing factors and heavy metals. This study aims to identify the factors that influence the spatial variation of lead (Pb) and cadmium (Cd) in 138 topsoil samples from the suburbs of Wuhan City, China, by using spatial regression models with MLR as the reference. Moran's I values reveal the spatial autocorrelation of Pb and Cd. The spatial lag model (SLM) outperforms MLR and has higher R2 and lower spatial dependence of residuals. The significant coefficients of the spatial lag term in SLMs indicate that the spatial variation of Pb and Cd depends on their surrounding observations. SLM results show that Pb content depends on the distance from the nearest industrial enterprises and suggest that industrial pollution is the main source of Pb. Cd content depends on pH, soil organic matter, and the topographic wetness index, indicating that intrinsic and topographical factors contribute to the spatial variation of Cd. Parent materials and application of phosphorus fertilizer are the most likely sources of Cd. The findings highlight the spatial autocorrelation of heavy metals and the effects of intrinsic factors and environmental variables on the spatial variation of such metals. Moreover, this study reveals the effectiveness of spatial regression models in identifying the influencing factors of heavy metals.
Zihao Wu; Yiyun Chen; Yiran Han; Tan Ke; Yaolin Liu. Identifying the influencing factors controlling the spatial variation of heavy metals in suburban soil using spatial regression models. Science of The Total Environment 2020, 717, 137212 .
AMA StyleZihao Wu, Yiyun Chen, Yiran Han, Tan Ke, Yaolin Liu. Identifying the influencing factors controlling the spatial variation of heavy metals in suburban soil using spatial regression models. Science of The Total Environment. 2020; 717 ():137212.
Chicago/Turabian StyleZihao Wu; Yiyun Chen; Yiran Han; Tan Ke; Yaolin Liu. 2020. "Identifying the influencing factors controlling the spatial variation of heavy metals in suburban soil using spatial regression models." Science of The Total Environment 717, no. : 137212.
Rapid monitoring of soil organic carbon (SOC) with fine sampling resolution is vital for further understanding of the global carbon cycle and sustainable management of soil resources. Proximal visible and near-infrared (Vis–NIR) spectroscopy is an effective approach to analyze SOC. However, this technique can only be used for point-to-point monitoring and not for grid pixels evenly spread throughout the area. Airborne hyperspectral imagery with high-spectral- and spatial-resolution provides a promising tool for mapping topsoil SOC at a fine scale, but suffers from the interference of some external factors. Using 45 topsoil samples collected from an agricultural field in the United States, this study aimed to compare the potential of airborne hyperspectral image in estimating and mapping of bare topsoil SOC with that derived from proximal laboratory Vis–NIR spectral data. Random forest (RF) along with two advanced feature selection algorithms, namely, continuous wavelet transform (CWT) and competitive adaptive reweighted sampling (CARS), was applied to optimize the performance of the prediction models. Results showed that laboratory and airborne spectra presented similar spectral shapes and strengths, but laboratory spectral curves were smoother than airborne spectral curves, which were noisier. Laboratory spectra (R2 = 0.79–0.87) performed better than airborne hyperspectral imagery (R2 = 0.49–0.76) in cross-validation, regardless of feature selection algorithms. The CWT-RF models resulted in the highest cross-validation results for laboratory (R2 = 0.87) and airborne (R2 = 0.76) spectra, suggesting their robustness in SOC prediction. The SOC maps retrieved from full-spectrum-RF, CWT-RF, and CARS-RF models all exhibited similar spatial distribution patterns. With airborne hyperspectral imagery serving as a valuable data source at pixel level for digital soil mapping, the methodological framework proposed in this paper could improve the accuracy and reduce the prediction uncertainty of SOC maps by selecting and adopting the optimal subset of spectral variables.
Yongsheng Hong; Songchao Chen; Yiyun Chen; Marc Linderman; Abdul M. Mouazen; Yaolin Liu; Long Guo; Lei Yu; Yanfang Liu; Hang Cheng; Yi Liu. Comparing laboratory and airborne hyperspectral data for the estimation and mapping of topsoil organic carbon: Feature selection coupled with random forest. Soil and Tillage Research 2020, 199, 104589 .
AMA StyleYongsheng Hong, Songchao Chen, Yiyun Chen, Marc Linderman, Abdul M. Mouazen, Yaolin Liu, Long Guo, Lei Yu, Yanfang Liu, Hang Cheng, Yi Liu. Comparing laboratory and airborne hyperspectral data for the estimation and mapping of topsoil organic carbon: Feature selection coupled with random forest. Soil and Tillage Research. 2020; 199 ():104589.
Chicago/Turabian StyleYongsheng Hong; Songchao Chen; Yiyun Chen; Marc Linderman; Abdul M. Mouazen; Yaolin Liu; Long Guo; Lei Yu; Yanfang Liu; Hang Cheng; Yi Liu. 2020. "Comparing laboratory and airborne hyperspectral data for the estimation and mapping of topsoil organic carbon: Feature selection coupled with random forest." Soil and Tillage Research 199, no. : 104589.
Chaohui Yin; Xuesong Kong; Yaolin Liu; Jing Wang; Zhen Wang. Spatiotemporal changes in ecologically functional land in China: A quantity-quality coupled perspective. Journal of Cleaner Production 2019, 238, 1 .
AMA StyleChaohui Yin, Xuesong Kong, Yaolin Liu, Jing Wang, Zhen Wang. Spatiotemporal changes in ecologically functional land in China: A quantity-quality coupled perspective. Journal of Cleaner Production. 2019; 238 ():1.
Chicago/Turabian StyleChaohui Yin; Xuesong Kong; Yaolin Liu; Jing Wang; Zhen Wang. 2019. "Spatiotemporal changes in ecologically functional land in China: A quantity-quality coupled perspective." Journal of Cleaner Production 238, no. : 1.
Yongsheng Hong; Ruili Shen; Hang Cheng; Songchao Chen; Yiyun Chen; Long Guo; Jianhua He; Yaolin Liu; Lei Yu; Yi Liu. Cadmium concentration estimation in peri-urban agricultural soils: Using reflectance spectroscopy, soil auxiliary information, or a combination of both? Geoderma 2019, 354, 113875 .
AMA StyleYongsheng Hong, Ruili Shen, Hang Cheng, Songchao Chen, Yiyun Chen, Long Guo, Jianhua He, Yaolin Liu, Lei Yu, Yi Liu. Cadmium concentration estimation in peri-urban agricultural soils: Using reflectance spectroscopy, soil auxiliary information, or a combination of both? Geoderma. 2019; 354 ():113875.
Chicago/Turabian StyleYongsheng Hong; Ruili Shen; Hang Cheng; Songchao Chen; Yiyun Chen; Long Guo; Jianhua He; Yaolin Liu; Lei Yu; Yi Liu. 2019. "Cadmium concentration estimation in peri-urban agricultural soils: Using reflectance spectroscopy, soil auxiliary information, or a combination of both?" Geoderma 354, no. : 113875.
Land surface area estimation can provide basic information for accurately estimating vegetation carbon storage under complex terrain. This study selected China, a country dominated by mountains, as an example, and calculated terrestrial vegetation carbon storage (VCS) for 2000 and 2015 using land surface area and traditional ellipsoid area. The land surface area is estimated by a triangular network on the high precision digital elevation model. The results showed that: 1) The VCS estimated by the surface area measurement in 2000 and 2015 were 0.676 and 0.692 Pg C (1 Pg = 1015 g) higher than the VCS calculated using the ellipsoid area, respectively. 2) As the elevation increases, the differences between VCS estimated by surface area measurement and ellipsoid area measurement are expanding. Specially, a clear gap was present starting from an elevation of 500 m, with the relative error exceeds 8.99%. 3) The total amount of carbon emitted due to land use change reached 0.114 Pg C. The conversions of forestland and grassland to other land use type are the main reasons of the loss of vegetation carbon storage, resulting in a total amount of biomass carbon storage decreased by 0.942 and 0.111 Pg C, respectively. This study was a preliminary exploration of incorporating land surface area as a factor in resource estimation, which can help more accurately understand the status of resources and the environment in the region.
Qingsong He; Shukui Tan; Peng Xie; Yaolin Liu; Jing Li. Re-assessing Vegetation Carbon Storage and Emissions from Land Use Change in China Using Surface Area. Chinese Geographical Science 2019, 29, 601 -613.
AMA StyleQingsong He, Shukui Tan, Peng Xie, Yaolin Liu, Jing Li. Re-assessing Vegetation Carbon Storage and Emissions from Land Use Change in China Using Surface Area. Chinese Geographical Science. 2019; 29 (4):601-613.
Chicago/Turabian StyleQingsong He; Shukui Tan; Peng Xie; Yaolin Liu; Jing Li. 2019. "Re-assessing Vegetation Carbon Storage and Emissions from Land Use Change in China Using Surface Area." Chinese Geographical Science 29, no. 4: 601-613.
The discovery of spatial clusters formed by proximal spatial units with similar non-spatial attribute values plays an important role in spatial data analysis. Although several spatial contiguity-constrained clustering methods are currently available, almost all of them discover clusters in a geographical dataset, even though the dataset has no natural clustering structure. Statistically evaluating the significance of the degree of homogeneity within a single spatial cluster is difficult. To overcome this limitation, this study develops a permutation test approach Specifically, the homogeneity of a spatial cluster is measured based on the local variance and cluster member permutation, and two-stage permutation tests are developed to determine the significance of the degree of homogeneity within each spatial cluster. The proposed permutation tests can be integrated into the existing spatial clustering algorithms to detect homogeneous spatial clusters. The proposed tests are compared with four existing tests (i.e., Park’s test, the contiguity-constrained nonparametric analysis of variance (COCOPAN) method, spatial scan statistic, and q-statistic) using two simulated and two meteorological datasets. The comparison shows that the proposed two-stage permutation tests are more effective to identify homogeneous spatial clusters and to determine homogeneous clustering structures in practical applications.
Qiliang Liu; Wenkai Liu; Jianbo Tang; Min Deng; Yaolin Liu. Two-stage permutation tests for determining homogeneity within a spatial cluster. International Journal of Geographical Information Science 2019, 33, 1718 -1738.
AMA StyleQiliang Liu, Wenkai Liu, Jianbo Tang, Min Deng, Yaolin Liu. Two-stage permutation tests for determining homogeneity within a spatial cluster. International Journal of Geographical Information Science. 2019; 33 (9):1718-1738.
Chicago/Turabian StyleQiliang Liu; Wenkai Liu; Jianbo Tang; Min Deng; Yaolin Liu. 2019. "Two-stage permutation tests for determining homogeneity within a spatial cluster." International Journal of Geographical Information Science 33, no. 9: 1718-1738.
The delimitation of three land management red lines (LMRLs), which refers to urban growth boundaries (UGBs), ecological protection redlines (EPRs), and basic farmland protection zones (BFPZs), has been regarded as a control method for promoting sustainable urban development in China. However, in many Chinese cities, conflicts extensively exist among the three LMRLs in terms of spatial partitioning. This study clarifies the connotation of conflicts among the three LMRLs. Moreover, a red line conflict index (RLCI) is established to characterize the intensity of conflicts among the three LMRLs. The Wuhan Urban Development Area (WUDA) is used for a case study, in which the spatial patterns of the three types of conflicts among the three LMRLs (i.e., conflicts between EPRs and BFPZs, EPRs and UGBs, and UGBs and BFPZs) are analyzed through numerous spatial statistical analysis methods (including spatial autocorrelation, urban-rural gradient, and landscape pattern analyses). In addition, the driving forces of these conflicts are identified from the perspectives of natural physics, socioeconomic development, neighborhood, policy and planning using three binary logistic regression models. Results show that the conflicts between EPRs and BFPZs, EPRs and UGBs, and UGBs and BFPZs are mainly distributed on the edge of the WUDA, inside Wuhan’s third circulation line, and at the urban–rural transition zone, respectively. The patch of conflict between BFPZs and UGBs has the lowest aggregation degree, the highest fragmentation degree, and the most complex shape. Logistic regression results show that the combination and relative importance of driving factors vary in the three types of conflicts among the three LMRLs. In the conflict between EPRs and BFPZs, the distance to city centers is the most important influencing factor, followed by the proportion of ecological land and elevation. In the conflict between UGBs and EPRs, the proportion of construction land, the distance to city centers, and whether the land unit is within the scope of a restricted development zone are the three most important factors. The proportion of construction land, the distances to the Yangtze and Han Rivers, and the proportion of cultivated land significantly influence the conflict between UGBs and BFPZs. This study aids in our understanding of the causes and mechanisms of conflicts among the three LMRLs, and provides important information for the “integration of multi-planning” and land management in Wuhan and similar cities.
Yang Zhang; Yanfang Liu; Xuesong Kong; Ying Jing; Enxiang Cai; Lingyu Zhang; Yi Liu; Zhengyu Wang; Yaolin Liu. Spatial Patterns and Driving Forces of Conflicts among the Three Land Management Red Lines in China: A Case Study of the Wuhan Urban Development Area. Sustainability 2019, 11, 2025 .
AMA StyleYang Zhang, Yanfang Liu, Xuesong Kong, Ying Jing, Enxiang Cai, Lingyu Zhang, Yi Liu, Zhengyu Wang, Yaolin Liu. Spatial Patterns and Driving Forces of Conflicts among the Three Land Management Red Lines in China: A Case Study of the Wuhan Urban Development Area. Sustainability. 2019; 11 (7):2025.
Chicago/Turabian StyleYang Zhang; Yanfang Liu; Xuesong Kong; Ying Jing; Enxiang Cai; Lingyu Zhang; Yi Liu; Zhengyu Wang; Yaolin Liu. 2019. "Spatial Patterns and Driving Forces of Conflicts among the Three Land Management Red Lines in China: A Case Study of the Wuhan Urban Development Area." Sustainability 11, no. 7: 2025.
Rapid urbanization accelerates urban expansion, especially in populous areas, such as Southeast Asia. The urban forms and changes at the macro level and the dynamics at the patch level are interrelated. Considering its spatiotemporal interdependences and global-local interactions, we propose a framework to quantify urban expansion by combining macro patterns and micro dynamics. Taking three Southeast Asian megacities, Bangkok, Ho Chi Minh City (HCMC), and Manila, as examples, we calculate the urban land densities in concentric rings (macro pattern) and the proximity expansion index (PEI) of new urban patches (micro dynamic) to compare the urban form changes and expansion patterns based on Landsat imagery in 1990, 2000, and 2014. The results show that the urban form changes have close relationships with the local urban patch dynamics. The macro- and micro-level results in Bangkok and Ho Chi Minh City are interrelated and consistent and the explainable inconsistent results in Manila further reveal the necessity of combination of two scopes. The three megacities developed in different manners, thereby resulting in diverse urban forms and changes. Other methods and technologies combining macro and micro perspectives are encouraged to better understand urban expansion.
Gang Xu; Limin Jiao; Jiafeng Liu; Zhongkui Shi; Chen Zeng; Yaolin Liu. Understanding urban expansion combining macro patterns and micro dynamics in three Southeast Asian megacities. Science of The Total Environment 2019, 660, 375 -383.
AMA StyleGang Xu, Limin Jiao, Jiafeng Liu, Zhongkui Shi, Chen Zeng, Yaolin Liu. Understanding urban expansion combining macro patterns and micro dynamics in three Southeast Asian megacities. Science of The Total Environment. 2019; 660 ():375-383.
Chicago/Turabian StyleGang Xu; Limin Jiao; Jiafeng Liu; Zhongkui Shi; Chen Zeng; Yaolin Liu. 2019. "Understanding urban expansion combining macro patterns and micro dynamics in three Southeast Asian megacities." Science of The Total Environment 660, no. : 375-383.
Africa has been experiencing rapid urbanization, yet limited studies have systematically investigated urban growth dynamics across African cities. Using 25 cities as cases, we quantified urban growth and form changes in Africa via spatiotemporal analysis of urban land densities in concentric rings over three time points (1990, 2000, and 2014). The results show that African cities have rapidly grown both in population and built-up areas, which increased by about 4% and more than 5% per annum, respectively. Urban land density (defined as the proportion of the built-up area to the buildable area) in each concentric ring decreases from the city center to the urban periphery with diverse patterns among cities. Comparatively, small cities have a lower urban land density and a more dispersed urban form than medium-sized and large cities in Africa. The international comparisons between cities with over one million population in Africa, Asia (e.g., China and India), Europe, and North America (i.e., the United States) reveal that African cities have a relatively less compact urban form. Implications of these findings for the future of African cities are further proffered.
Gang Xu; Ting Dong; Patrick Brandful Cobbinah; Limin Jiao; Neema S. Sumari; Baohui Chai; Yaolin Liu. Urban expansion and form changes across African cities with a global outlook: Spatiotemporal analysis of urban land densities. Journal of Cleaner Production 2019, 224, 802 -810.
AMA StyleGang Xu, Ting Dong, Patrick Brandful Cobbinah, Limin Jiao, Neema S. Sumari, Baohui Chai, Yaolin Liu. Urban expansion and form changes across African cities with a global outlook: Spatiotemporal analysis of urban land densities. Journal of Cleaner Production. 2019; 224 ():802-810.
Chicago/Turabian StyleGang Xu; Ting Dong; Patrick Brandful Cobbinah; Limin Jiao; Neema S. Sumari; Baohui Chai; Yaolin Liu. 2019. "Urban expansion and form changes across African cities with a global outlook: Spatiotemporal analysis of urban land densities." Journal of Cleaner Production 224, no. : 802-810.