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1.
Chandra Kant Pawe 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2018,118(1):88-100
Unplanned urban growth, particularly in developing countries has led to changes in land use/land cover (LULC). Numerous Indian cities face problems of unplanned LULC change due to nominal or non-existent planning efforts compounded by rapid urban population growth. The Guwahati Metropolitan Area (GMA) is one such urban centre. The present study assesses the trajectories of LULC change using Landsat imageries acquired in 1976, 1989, 2002 and 2015. Natural and semi natural vegetated area and artificial and natural water bodies decreased while built-up areas, cultivated and managed areas, and natural and semi natural non-vegetated areas increased. The built-up area increased from 23.9 in 1976 to 115.1 km2 in 2015 becoming the dominant land cover class accounting for 41.8% of the total geographical area. During this period, natural and semi natural vegetated land were reduced by 88.9 km2 at an annual rate of 2.2 km2. Over the years there was an increasing trend of built-up land and cultivated and managed areas in the peripheral areas of the city while natural and semi natural vegetated land diminished. Consequently, as in many other developing countries, there is an urgent need for the governmental authorities and other stakeholders to implement effective urban planning policies. 相似文献
2.
中国城市空间拓展与经济增长关系研究——以261个地级市为例 总被引：5，自引：2，他引：3
近年来,随着中国城市化进程不断加快,各地普遍出现了以低价出让农业用地,盲目投资房地产及城市基础设施,大规模兴建新城区为主要特征的城市蔓延现象。造成这种城市建成区低密度无序扩张的原因,除了不规范的城市用地转化机制外,很大程度上是源于对城市化与经济发展关系的不当认识。以全国261个地级市为例,基于1990~2010年城市社会经济发展数据,采用多元回归模型客观分析了中国城市土地蔓延与经济增长的关系。研究结果表明,在控制住城市固定资产投资、外商投资（FDI）、房地产泡沫效应等因素后,城市现有建成区面积及其扩展幅度与其人均国民生产总值并没有显著相关关系。也就是说,单纯追求城市建成区规模扩张并不能直接促进城市经济发展。 相似文献
3.
姆万扎是坦桑尼亚第二大城市，也是非洲发展最快的城市之一，近年来城市蔓延问题日益凸显。本文以遥感解译的姆万扎2000、2010、2015年3期土地利用数据为基础，运用GIS空间分析、用地增长弹性系数、景观指数等方法和指标，并结合实地调研和关键知情人访谈，分析了姆万扎2000年以来城市蔓延的空间特征及影响因素。分析结果表明：1）2000年~2015年间姆万扎城市以非正式聚落形式快速蔓延，建成区扩展速度和扩展强度迅速增加；蔓延主要占用裸地，其次是植被，侵占植被的速度迅速加快；2）城市蔓延主要沿3条主干道进行，属于“廊道式为主，填充式为辅”的扩展模式，形成指状的城市空间形态；建成区紧凑度逐渐下降，形状变得更加不规则；3）城市蔓延的主要区域和整体范围都在扩大，距离衰减特征明显,沿东南方向扩展强度最高；4）城市蔓延主要受到人口与经济增长、交通条件改善、土地制度问题及有效规划缺失等因素的影响。加强次干路和地方道路的规划和建设，制定及时、有效、符合地方背景的城市规划，是未来姆万扎控制城市蔓延的可能途径。 相似文献
4.
The expansion of medium-sized cities in Brazil has increased significantly since the 80–90's decades. In that period, most of the urbanization process was represented by the agglomeration of the population in the major metropolitan areas such as São Paulo and Rio de Janeiro. Nowadays, the rural-urban movement in Brazil is predominantly affecting cities with less than 1 million inhabitants, located particularly in the Center-West and in the Semiarid Northeast regions. The city of Teresina, the capital and largest city of the Brazilian state of Piauí, is one example that has shown an accelerated process of urban development. In this context, this paper seeks to discuss the urban sprawl of Teresina over the last four decades (1974–2014), associating its trends of urban expansion and population growth with their social and environmental implications. The results of our work indicate that urban sprawl in Teresina has been continuous over the years and getting faster in the 2010–2014 period. High demographic density areas are located mostly in peripheral zones, where the low-income population dominates. The population density varies across the city, and it is far from the standard proposed by the urban legislation. Thus, urbanization in Teresina is characterized by the sprawl of its municipal boundaries, intra-urban densification and verticalization, and an increase in population, especially in areas of low-income neighborhoods. 相似文献
5.
城市用地与人口的异速增长和相关经验研究 总被引：16，自引：5，他引：16
由于城市土地利用变化涉及的因素多，使获取动态研究研究所需的资料十分困难，所以，用少数几个主要因素定量地表达其变化就显得十分重要。从前人的成果，即以人口表示的城市位序-规模法则和建成区面积表示的位序-规模法则出发，绽绎出城市的用地规模和人口数量呈异速增长。这意味着，如果把整个城市看成是一个生命有机体，那么作为反映城市特征的城市用地规模和城市人口这两个重要变量，就是城市这个有机体的两个器官，他们的增长率是成比例的。还通过这个关系建立了城市建成区面积与市场人口和经济发展水平的数学模式。对我国部分城市的经验研究在一定程度上分别证明了这两经验关系。 相似文献
6.
从城市收缩的维度类别、维度数量、时序演化3个方面入手,提出了一套新的多维度分析框架,并将其应用于中国城市收缩的时空演变特征分析。结果表明：1）在1995—2000、2000—2005、2005—2010和2010—2015这4个时期中,人口收缩城市占中国城市总量的比例分别为9.55％、20.34％、15.34％和19.72％;经济收缩城市占比分别为5.32％、4.85％、0.47％和8.29％;空间收缩城市占比分别为7.04%、3.44%、3.76%和1.72%。2）相对于欧美发达国家,中国的城市收缩现象并不是很严重,大部分人口收缩城市的收缩率均低于3％。3）中国的城市收缩现象存在3个悖论：93.03％的人口收缩城市的建成区面积在扩张,92.37％的人口收缩城市的国内生产总值（GDP）在增长,94.57％的经济收缩城市的建成区面积在扩张。这与中国的要素依赖型经济增长模式和地方政府的土地融资模式等存在较强的关系。文章所构建框架具有较好的灵活性和较强的适应性,有助于增强收缩城市研究的可比性。此外,该框架在推动城市多维度收缩的类型学研究,分析城市收缩的时序演化规律等方面也具有较大的潜力。 相似文献
7.
Modeling Spatial Processes of Urban Growth in African Cities: A Case Study of Nairobi City 总被引：1，自引：0，他引：1
《Urban geography》2013,34(2):259-272
Africa's urban population growth has been especially rapid, averaging about 5% per year over the past two decades. As a result, many urban areas have experienced dramatic growth that is seriously outstripping the capacity of most cities to provide adequate services for their residents. Although population growth and urbanization rates in Africa have slowed recently due to a number of factors including HIV/AIDS, urban growth is still expected to double by 2030, leading to dramatic sprawl with serious environmental and social consequences. Using Nairobi as an example of a rapidly urbanizing African city, we studied the dynamics of land use and land cover change using satellite data and addressed the need for models and urban management tools that can guide sustainable urban planning policies. Cellular Automata, which integrate biophysical factors with dynamic spatial modeling, are used in this study. The model was calibrated and tested using time series of urbanized areas derived from land use/cover maps, produced from remotely sensed imagery, with future urban growth projected to 2030. Model assessment results showed high levels of accuracy, indicating that simulation findings were realistic, thereby confirming the effectiveness of the model. Results further showed that the model is a useful and effective tool to foresee the spatial consequences of planning policies in the context of many African cities. The forecast for Nairobi showed unsustainable sprawl. 相似文献
8.
土地扩张速度快于人口增长速度导致城市建成区总体人口密度下降,研究建成区人口密度的变化规律,对于城市健康发展决策具有重要意义。基于中国285个地级以上城市2006—2016年人口和建成区面积数据,分析中国城市建成区人口密度的变化趋势和空间分布差异,并探讨人口密度变化的驱动因素。结果表明：1）中国城市建成区平均人口密度由2006年的10 845人/km2降低至2016年的8 279人/km2,平均每年降低2.66%。2）超过5/6的研究城市的人口密度降低,但不同城市人口密度变化率存在显著差异。人口密度快速降低、中速降低、缓慢降低和密度增加的地级以上城市分别占比为13.3%、30.5%、41.1%和15.1%。3）人口密度快速降低城市主要分布在东部地区,人口密度中速降低和缓慢降低城市主要位于中部地区,人口密度增加城市呈现两极分化,主要包括北上深等人口快速流入城市和经济发展缓慢的小城市。4）经济发展水平、城市规模、区位因素、城市发展政策是影响人口密度变化的主要驱动因素。 相似文献
9.
2000-2009年长春、吉林城市蔓延特征、效应与驱动力比较研究 总被引：4，自引：0，他引：4
经济核心区是国家和地区经济增长、城市化发展的主要空间,也是城市蔓延最为严峻的区域。长(春)吉(林)一体化地区是中国图们江区域合作开发开放的先导区和东北地区的粮食主产区,肩负着“经济增长”、“人口城镇化”和“粮食安全”等多重责任。基于2000、2005、2009年的遥感图像和相关年份的统计年鉴,结合GIS和SPSS统计工具,对长、吉城市蔓延的程度、方式、效应与驱动力因子进行了比较分析。结果表明:用地扩展水平上长春市明显强于吉林市,且吉林市还表现出明显的阶段性特征;蔓延程度上,两市都表现出集约度低下、蔓延程度大的特性;蔓延方式上,长春市以“近域推进”式蔓延为主,吉林市以“轴带扩展”式蔓延为主;蔓延效应上,都带来了一系列负面效应,但长春市程度要重;在蔓延驱动力上,工业化和投资拉动是两者共同的主导影响因子,带有明显的政府导向性特征。文中提倡城市内部土地节约集约利用、区际培育城市群以形成合理的城市规模。 相似文献
10.
Darkness on the Edge of Town: Mapping Urban and Peri-Urban Australia Using Nighttime Satellite Imagery 总被引：1，自引：1，他引：0
Paul C. Sutton Andrew R. Goetz Stephen Fildes Clive Forster Tilottama Ghosh 《The Professional geographer》2013,65(1):119-133
This article explores the use of nighttime satellite imagery for mapping urban and peri-urban areas of Australia. A population-weighted measure of urban sprawl is used to characterize relative levels of sprawl for Australia's urban areas. In addition, the expansive areas of low light surrounding most major metropolitan areas are used to map the urban–bush interface of exurban land use. Our findings suggest that 82 percent of the Australian population lives in urban areas, 15 percent live in peri-urban or exurban areas, and 3 percent live in rural areas. This represents a significantly more concentrated human settlement pattern than presently exists in the United States. 相似文献
11.
城市化是建设用地扩展的主要驱动因素,分析建设用地时空演化格局已成为学者研究城市化过程的重要视角。采用空间自相关等方法,测度了1985年以来长江三角洲地区城市空间扩展的集聚特征并分析其演变过程;并结合格网建设用地密度频率的变化特点,将空间划分为不同的景观梯度地带,以此研究城市空间在不同地带中的扩展特点。研究结果表明,长三角城市空间扩展聚集程度先降后升,城市化区域融合趋势明显,并在城市空间扩展中表现出以上海、南京和苏州等为代表的3种模式,反应了长三角内部不同的经济发展特点。此外,在不同景观梯度下,长三角城市空间扩展表现出典型的阶段性特征。2000年以前在各个景观梯度下城市空间扩展差异较小,表现为较强的拓展性扩展;2000年以后,在城市核心区扩展强度加强,表现为填充式扩展加快。同时,城乡过渡区面积增加迅速,表明随着城市空间扩展的加速,长江三角洲地区城市土地不集约利用现象已较为突出。 相似文献
12.
Hany Abo-El-Wafa Kumelachew Yeshitela Stephan Pauleit 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2017,117(2):68-81
AbstractThe built-up area of Addis Ababa and its surrounding towns is expanding into the peri-urban region leading to high losses of farmland, directly influencing the food production for the urban population. This paper investigates the patterns of settlement growth in the region surrounding Addis Ababa and their impact on peri-urban agriculture using an urban spatial scenario design model. The effects of two population density scenarios are explored within the framework of a proposed master plan. The model output was used to estimate areas of different suitability levels that would be lost to the modelled settlement expansion. The settlement area in 2038 would represent 29% of the case study’s total area in the low-density scenario but only 19% in the high-density scenario. Compared to the low-density scenario, the high-density scenario would only require a third of the agricultural land transformed into settlement areas. Settlement development would contribute to higher losses of land suitable for cultivating important export products, high nutritional value and import-substituting products. The scenario approach can support sustainable regional planning for settlement expansion that conserves valuable farmland in the peri-urban area and contributes to building capacity for strategic planning of the city regions of sub-Saharan Africa. 相似文献
13.
中国城市土地扩张与人口增长协调性研究 总被引：10，自引：0，他引：10
基于城市建成区面积和城区人口数据,构建城市土地扩张与人口增长关系模型,对2000年和2010年中国657个城市的土地扩张与人口增长之间的协调性进行了评价。结果表明:①中国城市用地扩张和人口增长之间的协调性较弱,土地显著扩张是中国城市发展的主要类型,数量占城市总量的1/3;其次是人口显著增长类型,占城市数量的1/4,两极分化明显。②在空间分布上,土地显著扩张的城市主要集中在东部沿海、沿江、沿线等经济相对发达地区;人口显著增长的城市分布重心则相对西移,主要处于胡焕庸线以东的中西部地区。③从不同规模城市用地扩张与人口增长的协调性来看,特大城市、大城市发展以土地快速扩张为主,且土地显著扩张所占比例最大;中、小城市发展以人口快速增长为主,并以人口显著增长占优。④由城市规模变动来看,小城市规模晋升多以人口快速增长实现,大、中城市规模晋升则更多通过土地快速扩张推进,特别是以房地产、新城建设等带动的用地驱动型城市化来完成。 相似文献
14.
城市蔓延已成为具有普遍意义的现象,然而,城市蔓延内涵的争议性和模糊性问题一直没有得到很好的解决。本文将城市蔓延定义为一种低效、低密度、无序的城市空间开发模式,这种开发模式与中国城市高质量发展的目标和要求是相违背的。为实现对城市蔓延的宏观管理和精准调控,有效遏制城市蔓延带来的负面影响,本文开发了一套多维度、可比较的,并且与城镇化质量紧密关联的城市蔓延指数。基于卫星影像与人口、经济统计数据,选取代表城市蔓延核心特征的多个指标,采用主成分分析法计算了全国主要大城市2014年城市蔓延指数。结果发现,经济效率维主成分对综合蔓延指数贡献最大（41.30%）,人口密度维主成分次之（20.49%）,空间形态维主成分贡献率排第三（12.35%）。值得注意的是,许多经济发展较落后的城市因为经济效率维度的短板效应显著而被列入最蔓延的行列。此外,不同维度城市蔓延指数空间分布差异明显,并且综合蔓延指数与城市规模呈一定的负相关关系。 相似文献
15.
Controversy has arisen in recent years over the creation of so-called “ghost cities” across China. The ghost city term tends to describe large-scale urban areas, sometimes planned as new towns, featuring an abundance of new built space and appearing to also have extremely low tenancy. This article examines key questions related to the ghost city phenomenon, such as: what is a ghost city? Are ghost cities driven by a tendency toward over-supply in housing? How are local-level political incentives aligned to foster the production of ghost cities? Are ghost cities temporary anomalies or structural features of China’s urban-led economic growth model? We discuss recent scholarly research into ghost cities and present original findings to show how an excess of urban space may plague certain Chinese cities. 相似文献
16.
南京大都市区建设用地扩张特征与机理 总被引：6，自引：2，他引：4
作为全球城市化最快的地区之一,中国建设用地的扩张引起了广泛的关注。以长三角北翼中心城市南京为例,利用遥感、土地利用调查等数据研究大都市区建设用地扩张的过程、格局与机理。研究表明,1985-2007年南京市在工业化、城市化和国际化的推动下经济快速增长,引致了建设用地的扩张,年均增长率为3.14%。2001年后随着城市发展模式由单中心向多中心转换,建设用地呈加速扩展趋势。南京市建设用地扩展具有明显的沿长江和南北交通走廊轴向发展的特征。开发区和新城建设是南京市建设用地扩张的主要方式。区、县尺度的回归分析表明,人口增加、全球化是城镇工矿用地扩张的重要推手;经济的服务业化有利于土地集约利用,减少对用地的需求,这种影响在城区更大;在分权化竞争中,都市区政府具有更强的控制力。 相似文献
17.
18.
Luca Salvati 《Urban geography》2013,34(3):440-453
This study assesses changes in population distribution and the expansion of urban settlements in Southern Italy between 1871 and 2011. Four demographic phases are identified: (i) spatially balanced, mild population growth (1871–1921); (ii) moderate population increase concentrated in coastal and lowland areas (1921–1951); (iii) rapid and diffused population growth (1951–1981); and (iv) population stability with settlement dispersion (1981–2011). While urban growth in the years preceding the 1980s reinforced the polarization in rich and poor areas along the urban-to-rural gradient, since the early 1990s both urban and rural areas showed population dynamics that consolidated low-density settlements scattered around the largest cities. This path, however, does not reflect the evolution towards a more spatially balanced urban development, as observed in other European regions. Causes and consequences of the persistence of a fragmented urban hierarchy with dense settlements and sprawl concentrated around the main cities are finally discussed. 相似文献
19.
The global food system is coming under increasing strain in the face of urban population growth. The recent spike in global food prices (2007–08) provoked consumer protests, and raised questions about food sovereignty and how and where food will be produced. Concurrently, for the first time in history the majority of the global population is urban, with the bulk of urban growth occurring in smaller-tiered cities and urban peripheries, or ‘peri-urban’ areas of the developing world. This paper discusses the new emerging spaces that incorporate a mosaic of urban and rural worlds, and reviews the implications of these spaces for livelihoods and food security. We propose a modified livelihoods framework to evaluate the contexts in which food production persists within broader processes of landscape and livelihood transformation in peri-urban locations. Where and how food production persists are central questions for the future of food security in an urbanising world. Our proposed framework provides directions for future research and highlights the role of policy and planning in reconciling food production with urban growth. 相似文献
20.
Although Mediterranean cities have inherent differences on a local scale, together they offer a kaleidoscopic overview of distinctive morphologies and patterns of socio-spatial segregation. In this study, we explore the distribution of residential swimming pools as indicators of the use of land and water at the metropolitan scale, in relation to recent changes in the socio-spatial structure of a large Mediterranean city (Athens, Greece). Our results indicate a polarized spatial distribution of swimming pools, still considered a luxury affordable only for a minor segment of the Greek population. The analysis highlights the spatial linkages between concentration of residential pools, class segregation and low-density settlements, indicating that the socio-spatial structure of Athens remains characterized by persistent disparities between rich and poor neighborhoods. Comparison with another Mediterranean city (Barcelona) demonstrates the peculiarity of Athens’ recent development as reflected in the fragmented and polarized urban structure. The study provides an alternative reading of recent Mediterranean urban growth by considering pools as a “landmark” for urban sprawl, producing contested landscapes of localized social segregation. 相似文献