Urbanization,land use transformation and spatio-environmental impacts: Analyses of trends and implications in major metropolitan regions of Ghana

Urbanization induces spatial and environmental changes. Monitoring and understanding the nature of these changes is crucial to achieving sustainable urban development imperatives. To this end, this paper examines the evolution and spatio-environmental impacts of rapid urbanization in two major metropolitan regions of Ghana—Accra-City Region and the Greater Kumasi Sub-Region. The analysis uses Landsat satellite data and landscape metrics to examine land use transitions and to characterize the emergent landscapes over the last three decades. The results show that built-up land has increased significantly in these metropolitan regions largely at the expense of environmental land cover classes. The expansion process follows a general trend where the historical-core zones were initially sites of rapid land cover conversion to built-up, with settlements in the suburban and peripheral zones expanding in recent years and becoming integrated into the conterminous urban areas of the metropolitan regions. The analysis also uncovered a unique, dynamic and complex process whereby the urban-open-space class, being in a permanent state of flux, mediates transitions between built-up land and vegetation and vice versa. The metric-based land use transformation analysis shows that the landscape of the metropolitan regions has fragmented because of an increased expansion and aggregation of patches of built-up land in the core areas and leapfrog, sprawling expansion in the outlying suburban and peripheral zones. The paper concludes on the need for integrative urban growth management strategies that brings together spatial planning and environmental resource governance to avert the negative consequences on the natural environment of unfettered urban expansion.     

重庆市渝北区城市空间扩展模式分析

城市化过程的城区形态变异是以建设用地的向外扩展为显著特征的,而空间扩展的规律、过程和特征是衡量城市化发展水平和模式的主要标准。研究基于近二十年来重庆市渝北建成区时空分布情况,应用遥感与地理信息系统技术,分析了渝北建成区空间扩展的面积、速率、方向、模式以及区内的道路建设扩展情况,揭示了渝北建成区以及道路建设空间扩展的规律、过程和特征,为该区域的城市规划、城市水土资源管理和宏观调控决策等提供了科学的依据。     

快速城市化背景下的桂林市土地利用时空动态分析

以城市化快速发展的桂林市五城区为研究区,1991年和2006年两期TM遥感影像为数据源,利用光谱影像信息增强与监督分类相结合方法提取城市土地利用空间信息,同时借助GIS空间分析工具,对桂林市15年间的土地利用时空动态进行了分析。研究结果表明:全市各类土地利用面积发生了明显变化。城镇与居民点用地、水体和其它用地面积均有较明显增长,耕地、林地面积出现不同程度减少,城乡建设用地面积增长已成为整个区域土地扩展的主体;全市土地扩展强度指数和相对变化率存在较大区域差异,城镇与居民点用地、水体和其它用地面积在五城区均呈增长态势,其中城镇与居民点用地扩展强度指数变幅最大,七星区、叠彩区面积扩展最快,雁山区最小。耕地、林地分别以象山区和七星区减少速度最快;从缓冲区上看,城市土地扩张空间差异明显,城镇与居民点用地扩展主要集中在距市中心2～10km的建成区与边缘地带,该地带内的林地、耕地正逐渐被城乡居住、工业与交通用地所替代。     

Identifying the internal structure evolution of urban built-up land sprawl (UBLS) from a composite structure perspective: A case study of the Beijing metropolitan area,China

Differences in the internal composite structure during urban built-up land sprawl (UBLS) will generate different effects, and thus, a city’s spatial structure has important bearings on urban sustainability. This study investigates the spatial and temporal characteristics of the internal structure and allocation relationship of UBLS using multivariate spatial correlation and the Weaver-Tomas composite coefficient based on site data of granted built-up land parcels. Moreover, the composite structure evolution process of UBLS and its driving mechanism are examined in this study. The results reveal that the amount structure of the three types of UBLS (i.e. industrial land sprawl, residential land sprawl and commercial land sprawl) tended to be balanced during the study period. Following the transformation and upgrade of the urban industry structure, the overall composite structure of UBLS ranged from single residential land-use structure (Res.) to industrial-residential land-use structure (Ind.-Res.) In the early period of land marketization, the marketization land granting mechanism caused low spatial correlation between the various types of UBLS and a single composite structure, i.e. Res., single commercial land-use structure (Com.), and residential-commercial land-use structure (Res.-Com.). Subsequently, a dual-driving force including the market economy and government interventions caused a relatively high degree of spatial correlation and a multiple composite structure, i.e. Ind.-Res. and industrial-residential-commercial land-use structure (Ind.-Res.-Com.). However, the evolution characteristics of the composite structure in various regions illustrate some problems, such as the spatial isomorphism phenomenon of the composite structure and the dislocation of urban built-up land allocation. The urban internal built-up land spatial layout pattern is the embodiment of two dominant driving forces, the market and the government, interacting with each other according to natural and socioeconomic conditions. Therefore, we suggest that it is necessary to reform the future urban built-up land granting mechanism based on market guidance, and the composite structure of UBLS should be adjusted according to the regional function. The government should reinforce the macro-control of land-use planning for the dispersed granted land parcels so as to optimize the urban land-use structure.     

重庆市城市建设用地扩张与经济发展关联测度

[目的]为探求重庆市城市建设用地扩张与经济发展之间的关系,采用1997—2016年城市建设用地与经济发展数据,分析两者之间的动态关系,为重庆市合理确定城市发展边界,提升经济发展质量提供参考。[方法]采用协整检验、Granger因果检验和脉冲响应等计量分析方法分析重庆市城市建设用地扩张与经济发展之间的关联。[结果](1)城市建设用地扩张呈正异速增长类型,城市各功能性用地扩张具有明显的不均衡性,居住用地、工业用地和道路广场用地是城市建设用地扩张的主体。(2)城市建设用地扩张和经济发展存在长期均衡关系,两者呈同质性变化特征。(3)GDP在滞后1、2阶时,在90%、99%的置信水平下,经济发展是城市建设用地扩张的Granger原因;但城市建设用地是GDP增长的Granger原因并不明显,说明盲目地增加城市建设用地供给并不一定促进经济发展。(4)经济发展主要受自身波动的影响,短期内城市建设用地扩张对经济发展的贡献呈上升趋势,但增幅不大。经济发展对城市建设用地扩张的作用明显, 90%以上的城市用建设用地扩张在经济发展波动中得到解释。[结论]城市建设用地扩展对经济发展的贡献度有限,但经济发展是推动城市建设用地扩张的主要因素。未来应深化经济发展与城市空间关联的研究,制定差别化的城市建设用地扩张管控政策。     

资源型城市空间扩展研究——以徐州市为例

以我国东部地区典型资源型城市徐州市为例,综合集成MSS、TM、SPOT等遥感影像和地形图、城市历史地图及其它空间数据,在遥感、地理信息系统等技术支持下,通过扩展强度、分形雏数、扩展方向等指标分析了徐州市城市扩展的时空特征,并从自然、经济、社会等方面探讨城市扩展的驱动力.结果表明:建国以来的近60年间,徐州市城市空间显著...     

城乡交界带农村居民点用地演变规律研究——以济南市历城区为例

济南市历城区位于城乡、山地平原交界带,农村居民点用地影响因素多,特殊性强.以历城区土地利用现状图(1996年)、历城区第二次土地利用现状调查图(2008年)为依据,应用MAPGIS软件对1996-2008年农村居民点用地的扩展演变进行了定量分析.结果表明:研究期内,历城区农村居民点用地总面积呈增加趋势,全区共增加了34...     

基于低碳经济理念的城市住宅区土地集约利用水平测度

基于低碳经济理念构建城市住宅区土地集约利用水平测度指标体系,运用灰色定权聚类评估方法和比较分析法测度并对比分析低碳经济理念和传统理念下城市住宅区土地集约利用水平的差异.研究结果表明:低碳经济理念对城市住宅区土地集约利用提出了更高的要求,有利于促进城市住宅区土地合理集约利用;测度结果的对比反映了传统理念下土地集约利用存在的不足.     

Spatio-temporal pattern and driving forces of construction land change in a poverty-stricken county of China and implications for poverty-alleviation-oriented land use policies

Sustainable land use, targeted poverty alleviation (TPA) and integrated urban/town development are key issues for the poverty-stricken counties of China. This paper explored the spatio-temporal pattern and driving forces of construction land change in Longzhou, a typical poverty-stricken border county in southwest China, based on high-resolution remote sensing images and field investigations. The results showed that, from 2011 to 2016, the construction land in Longzhou increased by 10.08%. The largest increase shown by urban built-up areas (37.74%) followed by rural residential (25.48%), industrial and mining (20.96%), and transportation areas (15.49%) as well by tourist facility areas (0.33%). The accelerated urban development, rural housing construction, and construction of industrial parks and transportation facilities are main factors driving construction land expansion, while the implementation of TPA strategy and the booming of border trade activities are important policy drivers of the construction land expansion. Some of the major implications for improving poverty-alleviation-oriented land use policies were further discussed. The authors argue that land use policy innovation could play a key role in breaking the Matthew effect (poor get poorer, rich get richer) of China's uneven regional development and generating and accelerating the transformation development of poverty-stricken counties. It is fundamental to meet the demand of construction land for TPA, meanwhile raise the intensive level of land utilization. The authors suggest that the government need to further improve and implement preferential land use policies for poverty-stricken counties from the provincial level, appropriately increase the quotas of construction land, and effectively strengthen the rational, efficient and intensive use of the quotas of construction land, and provide solid land policy support for poverty alleviation and thus achieve the Sustainable Development Goals with higher quality.     

不同类型建设用地扩张的时序及空间特征——加速失效模型在静海区的应用

研究目的：分析城市扩展中交通用地、商住用地和工业用地扩张的时序特征、空间关系以及扩张时点的影响因素。研究方法：农地—建设用地转换最优时机理论；加速失效模型。研究结果：（1）不同类型建设用地在扩张过程中具有相互关联的时序和空间特征；（2）静海区交通用地引导了其他建设用地扩张的方向，而不同级别交通用地由于对建设用地和农用地影响的差异，加快或延缓了建设用地扩张的时机；（3）商住和工业用地在200— 400 m 范围内相互集聚，且商住用地产生的集聚效应强于工业用地。研究结论：细化建设用地类型以分析城市扩张的特征和机制，有助于城市扩展区的布局优化和集约发展。     

武汉市农地城市流转的基本态势及区域差异

根据武汉市近年来土地利用变化的详查数据资料,分析其农地城市流转的基本态势及区域差异。结果表明：耕地是武汉市农地城市流转的主要流出类型,且在质量等级上多为优质耕地;农地城市流转的区域差异表现明显,主要集中分布在城市主城区的新区及城郊区;其区域指向性变化亦明显,主城区扩展的建设用地主要以城市、建制镇、村庄等居民点用地为主,城郊区以交通用地及工矿用地为主。     

Monitoring land use and land cover changes in the mountainous cities of Oman using GIS and CA-Markov modelling techniques

As a result of the socioeconomic transformation, the rapid urban expansion of cities and towns in the Gulf Cooperation Council (GCC) states has predominately led to tremendous pressure on the limited natural resources and loss of productive lands. Indeed, the spatial patterns of urbanisation and their impacts on mountain resources and environment have received little attention, particularly in Oman. Predicting urban growth in the mountainous cities has the potential to better understand the interaction between the spatial growth patterns and the mountain topography. This study aims to analyse spatiotemporal dynamics of land use/land cover (LULC) (2008–2018) and simulate urban expansion (2008–2038) in Nizwa city, Al Dakhliyah governorate, Oman. Cellular Automata (CA)-Markov and geospatial techniques were utilised to assess and project urban growth and land cover changes. The analysis was based on three maps of LULC at equal intervals derived from satellite imageries: Landsat TM for 1998, 2008 and 2018, along with topographic spatial layers (elevation, aspects, and terrain slopes) derived from the ASTER digital elevation model. In addition, other spatial parameters (population density, proximity to urban centres, and proximity to major roads,) were incorporated in the simulation process. The findings revealed that the actual LULC change during 2008–2018 was 12,014 ha of net urban growth (418.5 % change), while the simulated change was expected to be 14,985 ha by 2028, with a total of 37,465 ha increase in the built-up area and urban growth by 2038. Although the topographic variability will control LULC changes, the urban expansion overly will occupy the arable land across the valleys along with the flat areas. During the next two decades, the built-up areas will dominant, with a large percentage of vacant land (net loss 12,813 ha) and vegetation cover (net loss 35 ha) will be gradually converted into residential land use. The output of the simulations in this research could serve not only as spatial guidelines for monitoring future trends of LULC dynamics, but also address the threats and deteriorates of urban sustainability in the Omani mountainous cities. Furthermore, identifying bare soils and vegetation areas that are susceptible to urbanisation is of value for the national strategy of future urban planning in Oman.     

城市化背景下赣江流域植被初级生产力的时空变化

城市化对植被初级生产力的变化具有重要影响,本文在前人研究的基础上进一步研究城市化过程中建设用地扩张等人类活动对植被初级生产力的间接影响,以赣江流域为例,探究了2000-2015年十五年里城市建成区变化情况,并从整个流域与城市两个尺度分析2000-2015年赣江流域植被初级生产力时空变化特征,探究了建成区面积与降水、气温等气象因子的关系。结果表明,2000-2015年赣江流域植被初级生产力除部分建设用地地区总体呈现上升趋势,其中非建成区呈现显著增加趋势,平均每年增加2.297 d/km²。在城市尺度上,随着建成区面积的增大,城市植被初级生产力也随着不断上升。另外,研究表明,气温与降水等气象因子对城市植被初级生产力具有一定的推动作用。     

How do centrality,population growth and urban sprawl impact farmland conversion in Norway?

A strong link has been observed between urbanization processes and conversions of farmland to built-up land. Most previous research has addressed such conversion of farmland in relation to the expansion of larger cities. However, broader analysis of both rural and central areas is needed to increase the empirical basis for these claims. Based on GIS analysis of farmland conversions, this paper aims to expand our understanding of how urban sprawl affects conversion of farmland. We find that most farmland in Norway is converted to built-up areas in relation to existing urban settlement areas. In line with population growth, urban areas in the most central municipalities experience the most significant urban sprawl and loss of farmland. Moreover, the remaining farmland is located in the same areas that already have converted the most. These areas also experience significant pressure for continued land take. Assuming current trends continue, future urban sprawl will pose great challenges for the preservation of farmland in land-use planning. New research and policies are required to handle these challenges more effectively.     

广东省城镇化与耕地保护矛盾及对策研究

随着区域经济发展和社会繁荣,城镇化进程逐步加快,城镇化会导致城镇建设用地扩展、耕地减少与耕地保护之间有较大的矛盾;介绍广东省2000年以来城镇化发展和耕地减少情况,分析了二者之间的显著相关性,提出协调城镇化与耕地保护的对策。     

基于多维城乡差异化人地特征的城区范围识别方法 ——面向中国多样本城市的实践探索

研究目的：基于概念辨析与方法演进分析，从城乡差异化人地特征入手，构建指标量化下的城区范围识别方法并应用于107个样本城市进行准确度校验。研究方法：文献资料法、归纳演绎法、实证分析法。研究结果：（1）城区概念中的实体地域认知日益深化，现有多类指标筛选法、遥感影像识别法、大数据与人工智能识别法三类识别方法且具有差异化应用特征；（2）可从人口、土地、产业、环境4个维度选取差异化特征要素并确定指标条件，构建以实体地域为基础的城区范围识别方法；（3）借助影像数据、矢量数据和统计数据，依次通过初步筛选获得城区初始范围，通过图斑功能、连接度、边界核查等判断获得城区实体地域范围，通过图斑占比、市政公用和公共服务设施等分析获得城区范围；（4）在方法准确度校验中，105个样本城市的城区实体地域范围面积与同年度建成区面积平均偏差为21.2%，趋势线斜率为0.825，判定方法有效。研究结论：本方法可应用于全国各区域城市的城区范围识别，未来可在人口指标增补、统计精度提升等方面进行优化并开展镇区、乡村空间识别的延续性研究。     

建设用地供应规模与结构对城市发展质量的影响研究

研究目的:分析建设用地供应规模、建设用地供应结构变化对城市发展质量的影响效应,为以提高质量为导向的新型城镇化战略提供参考。研究方法:采用构建综合指标体系的熵值法测度城市发展质量,运用空间计量模型对土地供给与城市发展质量的相关性进行验证分析。研究结果:无论是建设用地供应规模,还是建设用地供应结构(工业用地占比、商业用地占比、住宅用地占比、公共管理与公共服务用地占比),均与城市发展质量之间存在倒U型曲线变换关系,即建设用地供应规模和建设用地供应结构在服务于城市高质量发展的时候,均存在一个动态的最优值或者最优比例。研究结论:建设用地供应对城市发展质量的影响是动态调整的,需要根据建设用地供应和城市发展质量的实际情况来确定最优的建设用地供应规模和供应结构。     

Assessment of relation of land use characteristics with vector-borne diseases in tropical areas

Land use and land cover changes play an important role in the occurrence of vector-borne diseases. It is highly essential to identify the prominent changes responsible for its occurrence so that suitable measures can be adopted. An attempt was made to identify the prominent land use and land cover changes responsible for the spread of chikungunya, malaria, and dengue fever in the State of Kerala, India, using hierarchical cluster analysis and multiple regression analysis. Large extent of water bodies, low land and agricultural land played a significant role on the incidence of chikungunya and malaria. High population density, built-up area and agricultural area favoured dengue fever. Vector-borne diseases were found to be the lowest in places where there is no low land and with higher forest area. Inappropriate disposal of wastes generated in the built-up area might be the reason for the spread of dengue fever. Freshwater in drains of these areas is polluted and form breeding grounds for mosquitoes. Hence much attention is to be paid to provide appropriate treatment and disposal of wastes generated in the built-up area of the State In an evolving urban policy, priority is to be given to the installation of safe treatment and disposal facility of wastes especially, sewage, sullage, and solid waste. The protection of forest land also plays an important role. Economic policy instruments such as Payment for Environment Services (PES) schemes, may constitute a useful tool to encourage an improved land use management through appropriate price signals, such as, for instance, for the preservation of forested areas especially in proximity of highly populated urban environments.     

乡土依恋、城市融入与乡城移民宅基地退出意愿 ——基于福建厦门的调查

研究目的:揭示乡土依恋、城市融入等心理情感因素在乡城移民宅基地退出决策中的影响机理,为科学设计宅基地退出机制和政策体系提供参考。研究方法:理论分析法,结构方程模型。研究结果:(1)乡城移民宅基地退出决策受到城乡空间依恋的共同影响,乡土依恋越强烈,退出意愿越弱;城市融入程度越高,退出意愿越强。(2)在乡城空间转换中,乡土依恋对宅基地退出意愿的负向影响强于城市融入的正向影响,乡城移民只有真正融入城市后才会乐意退出宅基地。(3)乡城移民对宅基地作为私人财产和居住保障的产权认知对其退出意愿有负向影响,乡土依恋在其中起着显著中介作用。(4)相比老一代乡城移民,相对更高的城市融入和较低的乡土依恋感知使得新生代乡城移民退出意愿相对较高。研究结论:政策设计应重视城镇化过程中心理情感层面人地关系的作用,保持历史耐心,加强城乡联动,从促进进城农民的城市融入、满足过渡阶段多元需求等方面提升乡城移民宅基地退出意愿。     

Assessing the fragmentation of construction land in urban areas: An index method and case study in Shunde, China

The fragmentation of construction land due to decentralised urban development, disorderly mixed land use, and large-scale transportation infrastructure poses a threat to urban integrity. There is a need to quantify the fragmentation level in a consistent way for inclusion in planning-related decisions. In the context of China's urban sprawl, this study develops a quantitative and intuitive index approach that planners can use to analyse multiple fragmentation features of construction land within urban areas. The approach can be used in planning policy reviews for timely land-use assessment and can be integrated into urban planning processes for developing strategic land-use scenarios. The method was applied in Shunde, a typical urban area in southern China, and construction-land fragmentation and its impacts on environmental quality were analysed. The results show that the entire built-up area in Shunde displays a high level of fragmentation. Patches of industrial and rural residence have been identified specifically higher fragmentation level. The shortage of available construction land makes land consolidation within built-up areas very important in planning Shunde's future development. Moreover, the land shortage requires the progressive reduction of construction land fragmentation. The results of the study also indicate that although land fragmentation has been affected by transportation infrastructure and the existence of rivers and hills in this region, decentralised decisions from hierarchical local governance regimes have greatly exacerbated this situation. Shunde provides examples of typical land-use problems associated with quasi-urbanised regions in China; construction-land fragmentation is a greater determinant for the sustainable development of urban and rural areas than construction-land growth.