Development Of Urban Areas Research Articles

Study on the Evolution and Optimization of the Spatial Structure of the Oasis in the Arid Area: A Case Study of the Aksu River Basin in China.

To achieve high-quality sustainable development in arid areas based on the concept of ecological civilization, it is necessary to deeply study the territorial spatial structure characteristics. Taking the Aksu River Basin, an important ecological security barrier in northwest China, as an example, this paper follows the research idea of "feature analysis-suitability evaluation-conflict identification analysis-optimization" and constructs a comprehensive model based on the AHP-entropy weight comprehensive evaluation method, ArcGIS spatial identification analysis, variance coefficient-TOPSIS method, and NRCA. A comprehensive model based on the AHP-entropy power integrated evaluation method, ArcGIS spatial identification analysis, variance coefficient-TOPSIS method, and NRCA was constructed to guide the optimization of the territorial spatial layout by exploring the characteristics of territorial spatial pattern, the suitability of territorial spatial development, the identification of territorial spatial conflicts, and the efficiency and functional advantage of territorial spatial utilization in the study area. The results show that: (1) The spatial type of territorial space in the Aksu River Basin from 2000 to 2020 is dominated by ecological space, agricultural space, and urban space, and the three spatial boundaries are irregularly interlaced. (2) The spatial utilization conflict pattern of the Aksu River Basin has formed, and the general conflict area is overgrowing. (3) The overall efficiency of territorial utilization in the Aksu River Basin is low, with significant differences among county administrative units. (4) After optimization, the three types of space in the watershed are adjusted and refined into six functional areas: basic farmland protection area, rural development area, ecological protection red line area, ecological control area, urban development area, and industrial supporting construction area.

Assessing the groundwater loss risk in Beijing based on ecosystem service supply and demand and the influencing factors

Incorporating ecosystem service supply and demand into ecological risk assessment can overcome the limitations of the traditional assessment framework. However, most previous studies are about theoretical discussions and applications of the assessment frameworks are very limited. In this study, we proposed an ecological risk assessment framework based on the supply and demand of ecosystem services and applied this framework to assess groundwater loss risk in Beijing. We calculated the water conservation service supply using the water balance equation and estimated the demand of the service using socioeconomic data from multiple sources. Moreover, the risk characterized by the risk probability of groundwater loss based on the budget of water conservation service was quantified. Furthermore, we delineated the spatial distribution characteristics of groundwater loss risk and analyzed natural and socio-economic factors affecting the risk using the geographically weighted regression (GWR). We found that the spatial distribution of water conservation supply and demand showed a mismatch. Moreover, high and very high groundwater loss risks were mainly distributed in the urban areas and on the cropland, and the very low risks were mainly located in the mountainous areas of Beijing. The average risk values in more than half of the administrative districts were >0.75 and parts of the new urban development areas displayed high groundwater loss risks. According to the GWR model, the impacts of the natural factors on the groundwater loss risk displayed larger spatial variations than those of the socioeconomic factors. Among the factors, population density exhibited a positive effect in most areas of Beijing and mainly affected the groundwater loss risk by influencing the water conservation service demand. Our study can provide a new perspective for ecological risk assessment in social-ecological systems and may provide scientific basis for the reduction of groundwater loss risk in Beijing.

Toward contemporary city branding in the digital era: conceptualizing the acceptability of city branding on social media

PurposeThis study aims to propose a conceptual framework for the acceptability of city branding on social media. The conceptual framework of the acceptability of city branding is necessary to achieve a successful city brand in the social media era. It tries to develop the use of social media in city branding practices and its acceptability, especially in the areas of urban planning and development. The study also explores important issues in the use of social media and its acceptability in city branding practices.Design/methodology/approachThis study was initially conducted using a literature review of relevant, recent, and trustworthy scholarly publications (books, journals, reports, and proceedings) about city branding and acceptability from the electronic database by using relevant terms and keywords to find the relevant literature. The next step was to identify the essential variable described in the literature and assess how these are connected to one another. The last step was to create a conceptual framework using the variables that were found and their interrelationships.FindingsSocial media is crucial for determining a successful model of city branding strategy. Incorporating social media in the city branding process may lead to emerging bottom-up forms of influencing the city branding process, creating better-accepted city branding from wider audiences and guaranteeing a long-term successful city brand. The results of this paper indicate that one can utilize social media user-generated content (from residents and visitors), local government-created content, peer interaction, electronic word of mouth (e-WOM), and the engagement and participation medium to understand whether city branding is accepted by stakeholders through nine dimensions of acceptability: knowledge, information diffusion, experience, attachment, congruence, behavioral intention, perceived quality, engagement, and participation.Research limitations/implicationsThis research outcome can be used to evaluate and extend the classical theory of the acceptability of city branding, or even the overall umbrella term of branding, in the digital age. Despite its contribution, this study is not without limitations. The conceptual framework herein is best suited to a branded city with a high social media penetration rate to better represent real-life phenomena in the offline environment; in other contexts, it presents certain reliability concerns regarding its implementation.Social implicationsThe conceptual framework herein is best suited to a branded city with a high social media penetration rate to better represent the real-life phenomena in the offline environment; in other contexts, it presents certain reliability concerns regarding its implementation.Originality/valueThis research highlight some acceptability dimensions of city branding practice and also emphasize social media platform as useful tool to understand people's opinion, attitude and behavior. Combining these two concepts of the acceptability of city branding and the use of social media provides an opportunity to achieve the goals of meaningful, authentic and resilient city branding.

Determination of Solar-Surface-Area-to-Volume Ratio: Early Design Stage Solar Performance Assessment of Buildings

One of the main targets of globally aimed strategies such as the UN-supported Race to Zero campaign or the European Green Deal is the decarbonisation of the building sector. The implementation of renewable energy sources in new urban structures, as well as the complex reconstruction of existing buildings, represents a key area of sustainable urban development. Supporting this approach, this paper introduces the solar-surface-area-to-volume ratio (Rsol) and the solar performance indicator (Psol), applicable for evaluation of the energy performance of basic building shapes at early design stages. The indicators are based on the preprocessors calculated using two different mathematical models—Robinson and Stone’s cumulative sky algorithm and Kittler and Mikler’s model—which are then compared and evaluated. Contrary to the commonly used surface-area-to-volume ratio, the proposed indicators estimate the potential for energy generation by active solar appliances integrated in the building envelope and allow optimisation of building shape in relation to potential energy losses and potential solar gains simultaneously. On the basis of the mathematical models, an online application optimising building shape to maximise sun-exposed surfaces has been developed. In connection with the solar-surface-area-to-volume ratio, it facilitates the quantitative evaluation of energy efficiency of various shapes by the wider professional public. The proposed indicators, verified in a case study presented, shall result in the increased sustainability of building sector by improving the utilisation of solar energy and overall energy performance of buildings.

Response of habitat quality to urban spatial morphological structure in multi-mountainous city

Revealing the relationship between urban spatial morphological structure (USMS) and habitat quality (HQ) is of great significance for high-quality urban development. In this study, the central urban area of a typical multi-mountainous city (Guiyang, China) was taken as research area. Two-dimensional (2D) and three-dimensional (3D) characteristic indicators system of USMS was constructed. The InVEST model was used to evaluate the HQ in the study area, and the spatial pattern characteristics of USMS and HQ in the multi-mountainous city were analyzed. Finally, the response relationship of HQ to USMS was revealed through Pearson correlation analysis and curve fitting. The results showed that: (1) The average level of HQ in the study area is low and the spatial aggregation effect is obvious; the spatial distribution difference between the high value area and the low value area is significant; the high value area is mainly distributed in the area where the large area of urban green space (UGS) and the urban remnant mountains (URMs) are located, while the low value area is mainly distributed in the high-intensity urban construction area. (2)The URMs have a significant impact on the USMS within the city, the intelligibility(I), spatial permeability, spatial aggregation degree, and spatial traffic attraction potential were poor; the buffer zone within 4 km of the urban center is the core area of urban development, and the buffer zone within 15 km is the rapid urban development area. (3)Among the USMS indicators, Choice(C) was significantly positively correlated with the HQ, while the Connectivity(Con), I, Average height(AVH), and Otherness(O) were significantly negatively correlated with the HQ. (4)Stepwise regression results showed that USMS could explain the difference of HQ in the study area well, and the values of fitting coefficient R2 were 0.975, 0.837 and 0.945 in 2008, 2013 and 2018, respectively. (5)There was a quadratic function relationship between HQ and USMS principal component factor f, and there was a threshold effect, and the thresholds were 0.798 in 2008, 0.905 in 2013 and 0.474 in 2018, respectively. This study confirmed the response relationship of HQ to USMS and demonstrates the existence of a threshold, which has important reference significance for urban biodiversity conservation and high-quality urban development.

Sources of Contaminants of Emerging Concern in Groundwater of Barcelona Urban Area

Abstract. Groundwater is a vital resource for the development of urban areas, where the problem focuses on the quantity and on the quality of this freshwater resource. Barcelona is a good example as because currently groundwater is used for irrigation of parks and gardens and street cleaning due to its poor quality as drinking water source. Among the pollutants found in groundwater, of special interest are contaminants of emerging concern (CEC), as they pose a high risk to the aquatic environment and human health. The behaviour, spatial distribution and processes that control them in the aquatic environment are still uncertain and most of them are unregulated. In this paper we study the inputs and processes controlling the hydrochemistry of Barcelona urban groundwater with special emphasis on the CEC. We selected 29 CEC that were detected at high concentrations of up to 1 µg L−1 (e.g. gemfibrozil, benzotriazole, among others). Towards the higher zones we identify groundwater with relative low mineralization more proximate to the natural recharge composition, while towards the urban area the anthropic inputs are evident (e.g. nitrate concentrations range from 50 to 200 mg L−1). Near the Besòs river there is a clear contribution from this superficial water highly polluted, mostly from wastewater treatment plant (WWTP) discharges, and reducing conditions. The main contributor of CEC pollution in groundwater was the river-aquifer interaction (Besòs river), while towards the urban area it might come from sewage seepage and probably a minor input from urban runoff. The redox state of these waters seems to control the fate and occurrence of several of these CEC. The limitations of this study are restricted to a single sampling campaign, therefore these results should be corroborated with other sampling campaigns, including the seasonal variations, which would allow establishing more robust conclusions.

Mobility patterns consideration of educational facilities distribution model formulation in Southeast Malang Regional development plan

Regional disparities, and urban sprawl, will cause inequality in mobility between regions—one of the causes of the uneven distribution of educational facilities. The study of mobility patterns provides an overview of student movement patterns from and to school. The analysis is needed to determine the potential problems due to spatial disparities in the settlement Development Area. The research purpose; is (1) to obtain a model for determining the location and distribution of public schools based on mobility patterns in urban settlement development areas and (2) to obtain the model formulation for spatial planning distribution of educational facilities. This research uses a descriptive exploratory method with Space Syntax analysis. The research location was selected using the Classified Purposive Sampling method with an observation scale in the Development Area. The school zoning system has implications for equal distribution of education, reducing the mobility gap between regions, reducing congestion, air pollution, and dependence on motorized transportation. The study results of patterns of connectivity, accessibility, and mobility become a consideration for the placement of educational facilities in the Development Area. This study will improve the arrangement of spatial patterns and distribution of educational facilities based on studies of connectivity, regional accessibility, and student mobility.

Improving the management of public transport in Lithuania’s major cities in the context of sustainable mobility and multimodality

This paper analyses the problems of passenger transport management in the context of sustainable mobility and multimodality in major Lithuanian cities. The urban transport system, development, and problem areas in meeting consumer needs are discussed. The article also discusses the ways to promote the use of public transport services in sustainable mobility and multimodality by solving the problem areas of passenger transport management. The article analyses the attitude of residents of major Lithuanian cities towards the importance of sustainable mobility and multimodality. The factors that determine the decision of the inhabitants of the major Lithuanian cities to use sustainable mobility and multimodality are presented, and ways to improve the quality in this area are considered. A quantitative method is applied to study the previously described attitudes and confirm the hypothesis that there are specific management difficulties related to sustainable mobility and multimodality. According to the study, most residents of Vilnius and other major cities do not combine public transport with other modes. Only less than one-third of survey participants combine multiple modes of transport on their trips. Implementing public transport management solutions in the context of sustainable mobility and multimodality should become a model.

The Role of Globalisation in Baku's New City

This article examines the construction of Baku city, which has undergone rapid change in recent years following the effects of globalisation, and where many new and iconic buildings have been built. These buildings have influenced the formation of Baku's new city image. The study focuses on how the texture of the newly built (2009-2018) contemporary buildings, primarily medium and large-scale projects, in intense development areas have affected the city's architectural identity.The selected 27 buildings were examined according to seven developed design criteria that examine the features affecting architectural identity. The results obtained with the findings are presented in the tables. Within the examination of the architectural development of Baku, the regions where the new buildings are mostly built, the west coast of the Caspian Sea and the urban development area Haydar Aliyev Street are discussed. While the still young 27-year-old republic focused on the intense modern city image, there were losses in the interesting urban and architectural texture during the period.

Agricultural space function transitions in rapidly urbanizing areas and their impacts on habitat quality: An urban–Rural gradient study

Agricultural space functions in rapidly urbanizing areas experience rapid transition with urban–rural development process, leading to habitat fragmentation and degradation. Previous studies focused more on impacts of agricultural landscape patterns on habitat quality at the regional scale, ignoring transition processes of agricultural space functions and functional combinations under an urban–rural gradient perspective and their different impacts on habitat quality. This study constructed a holistic framework oriented by four main agricultural space functions, including production, living, ecological, and landscape culture functions, to map transition characteristics of agricultural space function combinations in the main urban area of Hangzhou, a typically rapidly urbanizing area in China, from 2000 to 2019 under the urban–rural gradient. Impacts of these transition processes on habitat quality were further investigated.The results showed that spatiotemporal differences in variations of various agricultural space functions leaded to urban–rural gradient changes in the transition of agricultural space function combinations. From the urban development area to the urban–rural transition area and rural development area, the dominant output type was the single function area, while the dominant input type was the comprehensive function area, composite function area, and single function area, respectively. Areas with decreased habitat quality were mostly concentrated around urban construction land, and they had the highest proportion in the urban development area. All transition types in the urban development area had a negative impact on habitat quality, while the transition process from a more complex function combination to a simpler one in the urban–rural transition area and rural development area had a greater positive impact, and areas transformed from the lagged development area to other functional combinations also produced a positive impact. These findings provide ideas for rational spatial decision-making about limited agricultural resources in rapidly urbanizing areas.

Study of the Effect of External Magnetic Fields on the Parameters of the Electrical Communications Probing System for a Microtunneling Shield

The issues were reviewed in assessing external electromagnetic fields’ effect on the parameters of an electrical power line probing system based on three-component ferroprobes for detecting active underground power cable lines during microtunnel construction using the thrust boring method (by tunneling shield) in densely populated urban areas. A study was conducted on the change in the topology of the energized cable magnetic field located in the external magnetic field area created by operating electrical equipment under the influence of an external electromagnetic field and a tunneling shield with installed magneto-sensitive detectors. Experimental studies of the probing system were made. Options have been proposed for compensating the inductance component of the external magnetic field during tunnel driving in urban development and industrial area conditions.

Occurrence and Source Identification of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans and Polychlorinated Biphenyls in Surface Sediments from Liangshui River in Beijing, China

Polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls were measured in the surface sediments of Liangshui River, the second largest drainage river in Beijing, China. The sum concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls ranged from 3.5 to 3019 (mean value: 184) pg g-1 dry weight and from 319 to 5949 (mean value: 1958) pg g-1 dry weight, and the corresponding World Health Organization toxic equivalent quantity values were 0.0011-5.1 pg TEQ g-1 dry weight and 0.0074-1.4 pg TEQ g-1 dry weight, respectively. The spatial distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls showed increasing trends from urban area and development area to suburb. Principal component analysis revealed that polychlorinated dibenzo-p-dioxins and dibenzofurans contamination in the sediments may originate from pentachlorophenol and sodium pentachlorophenate and municipal solid waste incineration. Regarding polychlorinated biphenyls, the steel industry, combustion processes and usage of some commercial polychlorinated biphenyl products were identified as the major sources. The emission from a former steel plant could be the main contributor to polychlorinated biphenyls in urban areas. The mean value of the total toxic equivalent quantities in the sediment samples exceeded the Canadian interim sediment quality guidelines. Long-term wastewater irrigation increases the load of sediment-bound pollutants in agricultural soil and may pose potential ecological risks to crops and human health.

The effects of urban land use gradients on wild bee microbiomes.

Bees and their microbes interact in complex networks in which bees form symbiotic relationships with their bacteria and fungi. Microbial composition and abundance affect bee health through nutrition, immunity, and fitness. In ever-expanding urban landscapes, land use development changes bee habitats and floral resource availability, thus altering the sources of microbes that wild bees need to establish their microbiome. Here, we implement metabarcoding of the bacterial 16S and fungal ITS regions to characterize the diversity and composition of the microbiome in 58 small carpenter bees, Ceratina calcarata, across urban land use gradients (study area 6,425 km2). By categorizing land use development, green space, precipitation, and temperature variables as indicators of habitat across the city, we found that land use variables can predict microbial diversity. Microbial composition was also found to vary across urban land use gradients, with certain microbes such as Acinetobacter and Apilactobacillus overrepresented in less urban locations and Penicillium more abundant in developed areas. Environmental features may also lead to differences in microbe interactions, as co-occurrences between bacteria and fungi varied across percent land use development, exemplified by the correlation between Methylobacterium and Sphingomonas being more prevalent in areas of higher urban development. Surrounding landscapes change the microbial landscape in wild bees and alter the relationships they have with their microbiome. As such, urban centres should consider the impact of growing cities on their pollinators' health and protect wild bees from the effects of anthropogenic activities.

Health and Environmental Co-Benefits of City Urban Form in Latin America: An Ecological Study.

We investigated the association of urban landscape profiles with health and environmental outcomes, and whether those profiles are linked to environmental and health co-benefits. In this ecological study, we used data from 208 cities in 8 Latin American countries of the SALud URBana en América Latina (SALURBAL) project. Four urban landscape profiles were defined with metrics for the fragmentation, isolation, and shape of patches (contiguous area of urban development). Four environmental measures (lack of greenness, PM2.5, NO2, and carbon footprint), two cause-specific mortality rates (non-communicable diseases and unintentional injury mortality), and prevalence of three risk factors (hypertension, diabetes, and obesity) for adults were used as the main outcomes. We used linear regression models to evaluate the association of urban landscape profiles with environmental and health outcomes. In addition, we used finite mixture modeling to create co-benefit classes. Cities with the scattered pixels profile (low fragmentation, high isolation, and compact shaped patches) were most likely to have positive co-benefits. Profiles described as proximate stones (moderate fragmentation, moderate isolation, and irregular shape) and proximate inkblots (moderate-high fragmentation, moderate isolation, and complex shape) were most likely to have negative co-benefits. The contiguous large inkblots profile (low fragmentation, low isolation, and complex shape) was most likely to have mixed benefits.

GIS-based land-use suitability analysis for urban agriculture development based on pollution distributions

With recent increases in urban population and development, agricultural lands have been changed to residential areas and industrial settlements. Such urban population growth increases necessitate emerging relatively new strategies and forms in urban parks and landscape designs to meet today's economic, social, and ecological needs toward sustainable development. Urban agriculture is one of the strategies for achieving sustainable development and creating multi-purpose landscapes. Such an approach appears to partially solve the problem of agricultural land reduction and degradation. However, urban pollutants seem to hinder the development of such a sustainable concept in the cities. This research aimed to identify suitable locations for urban agriculture in urban green spaces according to various contamination criteria and the uniform distribution of the green spaces in Mashhad, Iran. In this research, using an Analytical Hierarchy Process (AHP) and a Geographic Information System (GIS) facilitated the decision-making process. It also determined the importance of the land use criteria for urban agricultural development. The results showed that the most suitable areas for urban agricultural development with the least impact of pollutants in Mashhad were the suburbs, especially in the northeast and southeast parts. These research results have practical implications for planning urban agricultural development at the city level across the world.

The assessment of land suitability for urban development in the anticipated rapid urbanization area from the Belt and Road Initiative: A case study of Nong Khai City, Thailand

The Belt and Road Initiative is a megaproject expected to accelerate urban growth. However, the accompanying urban development process can endanger the environment. Thus, land suitability assessment for urban development is crucial to cope with the urban expansion, especially in the anticipated rapid urbanisation areas. This study aims to assess the land suitability for urban development in Nong Khai City, Thailand. Eighteen criteria were selected to indicate suitability by integrating the analytical hierarchy process with the geographical information system. The results showed that the policy to conserve the cultural assets, flood, and the policy to conserve the natural assets have the biggest influence on the decision-making for urban development areas. Precisely 24.73% of the areas were very highly suitable for urban development, most of which are flood-free with high accessibility and high suitability regarding policy. Precisely 12.10% of the areas were very lowly suitable for urban development, most of which are prone to flooding, have low accessibility, and are distributed in the zones under the policy to conserve natural assets. The results highlighted how the suitability map for urban development is utilized in urban planning and provided evidence to support urban planning in the context of small cities.

The Spatial Spillover Effect and Its Impact on Tourism Development in a Megacity in China

By utilizing the tourism development data of Beijing for the period from 2010 to 2019, this study examined the spatial pattern distribution of tourism development in Beijing using the coefficient of variation and Moran’s I index. In addition, the geographic detector method was employed to explore the impact of tourism resource investment, tourism reception facilities, and urban development level on the spatial pattern of tourism development. The results indicate that the spatial differences in tourism development in various Beijing districts are gradually expanding, mainly focusing on the differences between urban function expansion regions. The number of tourists shows a spatial distribution pattern including a core area, urban function expansion area, ecological conservation area, and new urban development area. The spatial correlation of tourism development increases gradually, and some parts show the spatial correlation form of low–high aggregation. Tourism resource investment, tourism reception facilities, and urban development level all play a significant role in promoting the spatial pattern of tourism development, among which the most obvious role is the interactive effect of tourism reception facilities, star-rated hotels, and openness. Therefore, to improve the development of Beijing’s tourism industry, the government needs to pay attention to the differences in the expansion of urban functions, the degree of contact between regions, the number of tourism reception facilities, and the level of regional openness. The significance of this research is in promoting spatial governance, coordinated development among regions, and the high-quality development of tourism in Beijing, and laying down a foundation for the introduction of spatial collaborative governance policies in other megacities in China.

Assessment of environmental hazards at El-Galala El-Bahariya Plateau, Gulf of Suez, Egypt, using spatial multihazards assessment modeling

Environmental multihazard assessment modeling is essential for developing plans to mitigate the impact of future risks. They can be generated for a specific location by combining assessment maps of different types of natural hazards. Multiple approaches were used in this study to achieve an analytical hierarchy. “, including the usage of a geographical information system (GIS), fieldwork, geoanalytical studies, and chemical analysis” for an improved flow of information. The assessment maps of risk factors were initially produced. Subsequently, these maps were combined into a single map of multihazards using a spatial decision model. Hazard analysis indicated that the central part of the El-Galala El-Bahariya Plateau in the study area had the steepest slope (near vertical and classified as “high” to “very high”). The central part of the El-Galala El-Bahariya Plateau is the second largest part of the study area. Numerous tourist resorts have been established at this site. The rock formation in the research area was partially comprised very weak micrite limestone. Micrite limestone exceeds the recommended limits at 20% of the total rock formation. Unfortunately, projects aimed at attracting tourists have been built on deteriorating rocks, increasingly becoming of poorer rock quality. The results showed that parts of the study area become vulnerable to natural hazards due to its tectonic history and particular rock formation. The produced multihazard map indicated that the most suitable areas for urban development were located in the eastern part of the mountains. A safety zone limiting the location of tourist resorts would be required. To avoid rock deterioration and dissolution, unplanned waterwaste systems would have to be prohibited, and isolated waste pipes would be constructed. Environmentally friendly geotechnical solutions should be used to increase the rock strength, end rock destruction, and reduce hazard exposure.

The potential ecological risk assessment of soil heavy metals using self-organizing map

Heavy metal pollution control zoning aiming at the health maintenance of watershed soil ecosystem has become an important means of soil environmental protection and governance. Based on the self-organizing map (SOM), this study classifies the data sets of eight heavy metals such as Co, Cd, Zn, Cr, Cu, Pb, Ni, and Tl in 354 samples, calculates the potential ecological risk value of soil heavy metals in combination with the potential Hakansom Risk index (HRI), and uses the geographic information system (GIS) for visualization. In the research results, SOM has divided five soil ecological risk categories. The highest average ecological risk value of 85.95 is found in cluster IV, which is clustered and distributed in urban development areas in the upper reaches of the river. The average ecological risk values of cluster I and cluster V are relatively close at 79.64 and 79.19, respectively. Cluster I and cluster V are distributed in the north of the river in a linear and cluster manner, respectively, and are located on a concave bank with a relatively gentle slope. The average ecological risk of soil pollution in cluster II is 77.59, which is linearly distributed on both banks of the river. The ecological risk of soil pollution in cluster III is the lowest (74.39), mainly scattered in the south of rivers with less human activities. The study further identified the environmental factors that affect the soil ecological risk value in different cluster units and put forward the classified and differentiated management and control strategies for different cluster units. The research shows that SOM can cluster the data sets of heavy metals with high sensitivity and low threshold through competitive learning to effectively provide the distribution information of abnormal soil ecological risk areas. This information is helpful for urban environmental management departments and planning departments to take targeted management and recovery measures to avoid the health risks related to soil heavy metal pollution.

Three-Dimensional Urban Morphology Transformation of Coal Mining Cities: Case Study of Tangshan

Coal mining cities in China are in a significant era of urban spatial transformation. However, most of the existing studies have ignored the three-dimensional built environment and the impact of subsidence areas on the whole city, which has made it difficult to grasp the spatial development process of coal mining cities. In this study, we defined the subsidence areas and seismic zones as unstable regions and the other areas as stable regions. On this basis, a framework of cognition and evaluation of the transformation of both regions was constructed, by using three-dimensional urban morphology types (3D-UMTs), a landscape expansion index (LEI), and an urban transformation evaluation system. Lunan District and Lubei District of Tangshan were selected as the study area, and the time range was set from 2000 to 2018. The results indicated that the whole study area had experienced inefficient urban spatial transformation during the time span. This study also proved that considering unstable regions made the evaluation of the spatial form transformation of coal mining cities more accurate. The urban transformation evaluation system is helpful to visualize and evaluate the implementation of existing policies and assist decision-makers with delineating key areas for future urban development.