Quantitative Analysis of Spatial Vitality of Urban Built-up Area: A Case Study of Shenzhen

As an important goal of urban design research,the evaluation of urban spatial vitality has been widely concerned.Taking Shenzhen as an example,the urban built-up area of Shenzhen was identifi ed using improved DENsi-Graph analysis,from the perspective of quantifi cation of urban spatial morphological features.The accessibility of urban streets,degree of construction and architectural form,and degree of functional mixing were quantitatively analyzed through space syntax,space matrix and mixeduse index(MXI),and the spatial vitality of urban built-up area was evaluated.Research results demonstrated that the improved Densi-Graph analysis could better identify the built-up area of Shenzhen,and the overall classifi cation accuracy was 0.810.The analysis results of spatial vitality showed that the urban spatial vitality in Shenzhen urban built-up area was well created.The street accessibility of Shenzhen generally hindered the creation of urban vitality;the spatial matrix value in the north of Shenzhen urban built-up area was lower;and the MXI of most areas within the study area was above the medium.

Assessment of Human Impacts on Vegetation in Built-up Areas in China Based on AVHRR,MODIS and DMSP_OLS Nighttime Light Data,1992–2010

Since the reform and opening-up program started in 1978,the level of urbanization has increased rapidly in China.Rapid urban expansion and restructuring have had significant impacts on the ecological environment especially within built-up areas.In this study,ArcGIS 10,ENVI 4.5,and Visual FoxPro 6.0 were used to analyze the human impacts on vegetation in the built-up areas of 656Chinese cities from 1992 to 2010.Firstly,an existing algorithm was refined to extract the boundaries of the built-up areas based on the Defense Meteorological Satellite Program Operational Linescan System(DMSP_OLS)nighttime light data.This improved algorithm has the advantages of high accuracy and speed.Secondly,a mathematical model(Human impacts(HI))was constructed to measure the impacts of human factors on vegetation during rapid urbanization based on Advanced Very High Resolution Radiometer(AVHRR)Normalized Difference Vegetation Index(NDVI)and Moderate Resolution Imaging Spectroradiometer(MODIS)NDVI.HI values greater than zero indicate relatively beneficial effects while values less than zero indicate proportionally adverse effects.The results were analyzed from four aspects:the size of cities(metropolises,large cities,medium-sized cities,and small cities),large regions(the eastern,central,western,and northeastern China),administrative divisions of China(provinces,autonomous regions,and municipalities)and vegetation zones(humid and semi-humid forest zone,semi-arid steppe zone,and arid desert zone).Finally,we discussed how human factors impacted on vegetation changes in the built-up areas.We found that urban planning policies and developmental stages impacted on vegetation changes in the built-up areas.The negative human impacts followed an inverted′U′shape,first rising and then falling with increase of urban scales.China′s national policies,social and economic development affected vegetation changes in the built-up areas.The findings can provide a scientific basis for municipal planning departments,a decision-making reference for government,and scientific guidance for sustainable development in China.

Examining Rate of Built-Up Areas on the Vegetation Cover along River Riara Riparian within Kiambu Town, Kenya

Urban river riparian spaces and their natural systems are valuable to urban dwellers;but are increasingly affected and ruined by human activities and in particular, urbanization processes. In this research, land sat and sentinel satellite imagery apt for change detection in vegetation cover, both landsat and sentinel imagery, covering the period between 1970 and 2021 in epochs of 1973, 1984, 1993, 2003, 2015 and 2021 years were used to establish the correlation between vegetation cover and built-up area along River Riara river reserve. The images were analysed to extract the built-up areas along the river reserve, including the buildings, and the rate of human settlements, which influenced vegetation cover. Normalized Difference Built-Up Index (NDBI) and Normalized Difference Vegetation Index (NDVI) were computed using the Short-Wave Infrared (SWIR) and the Near Infra-Red (NIR) bands to show the rate of change over the years. Results indicate NDVI values were high, compared to NDBI values along river Riara in the years 1973 and 1993 implying that there was more vegetation cover then. However, in the year 2021, the NDVI indicated the highest value at 0.88, with the complementary NDBI indicating the highest NDBI value at 0.47. This represents a significant increase in built-up areas since 2015 more than in previous epochs. Either, there was a significant increase in NDBI values, from 0.24 in 1993 to 0.47 in 2021. More so, the R-squared value at 0.80 informed 80% relationship between NDBI and NDVI values indicating a negative correlation.

Dynamics of Urbanization and Its Impact on Land-Use/Land-Cover: A Case Study of Megacity Delhi

The rapid expansion of urban areas due to rise in population and economic growth is increasing additional demand on natural resources thereby causing land-use changes especially in megacities. Therefore, serious problems associated with rapid development such as additional infrastructure, informal settlements, environmental pollution, destruction of ecological structure and scarcity of natural resources has been studied carefully using remote sensing and GIS technologies for a rapidly grown megacity namely, Delhi. The present work evaluates the land use/land cover (LULC) changes and urban expansion in Mega city Delhi and highlights the major impact of rapid urbanization and population growth on the land cover changes which needs immediate attention. The results indicate that the city is expanding towards its peripheral region with the conversion of rural regions in to urban expansions. Built-up area of Delhi witnessed an overall increment from 540.7 km2 to 791.96 km2 or 16.86% of the total city area (1,490 km2 ) during the study period 1997 to 2008 which mainly came from agriculture land, waste land, scrub-land, sandy areas and water bodies. The increment in forest cover of 0.5 % is very small when considering the increment in built up category to 17%. Total area of waterbodies has reduced by 52.9% in a ten year period (58.26 km2 in 1997 to 27.43 km2 in 2008) with shallow waterbodies now having a dismal presence. LULC changes are studied with the urban growth parameters such as population, vehicles, gross state domestic product etc. The results lay emphasis on the concepts of urban planning to be applied such that more consideration is towards the preservation and management of natural land use classes which will increase the quality of life in an urban environment.

Statistical Change Detection in Water Cycle over Two Decades and Assessment of Impact of Urbanization on Surface and Sub-Surface Water Flows

Urbanization is termed as physical transformation of landscapes that alter the natural regime of the environment of its surrounding resulting in further changes in macro as well as micro climate of the region [1]. Urban areas are continually facing problems of water scarcity and urban flash floods. Recent news from IPCC report 2010, CIESIN’s Global Rural Urban Mapping Project [2] and World Water Vol. 7 2007, it is clear that urban land area has doubled and affected the hydrological cycle. The components of hydrological cycle affected are Infiltration, Runoff and Evaporation and the causing components are derived by studies as land use, land cover, water withdrawal and urban developments. Thus water availability, water recharge and water cycle are all destabilized in course or urban development. The paper is an attempt to correlate and identify the periodical changes in urban water cycle, during urbanization of Bhopal City, India, during last twenty years and above. The observations are based on GIS mapping of the study area from 1991 to 2009 using rational method of runoff and recharge calculations and statistical analysis of related built-up areas. Also change in natural course of drainages with the help of GIS imageries which have been detected during twenty years that help to observe the adaptation of natural system to urban course. Also the observations show an interesting relation which can be used for further research and sustainable development [3].

Analysis of the Relationship between Land Surface Temperature and Vegetation and Built-Up Indices in Upper-Hill, Nairobi

Designing “liveable” cities as climate change effects are felt all over the world has become a priority to city authorities as ways are sought to reduce rising temperatures in urban areas. Urban Heat Island (UHI) effect occurs when there is a difference in temperature between rural and urban areas. In urban areas, impervious surfaces absorb heat during the day and release it at night, making urban areas warmer compared to rural areas which cool faster at night. This Urban Heat Island effect is particularly noticeable at night. Noticeable negative effects of Urban Heat Islands include health problems, air pollution, water shortages and higher energy requirements. The main objective of this research paper was to analyze the spatial and temporal relationship between Land Surface Temperature (LST) and Normalized Density Vegetation Index (NDVI) and Built-Up Density Index (BDI) in Upper-Hill, Nairobi Kenya. The changes in land cover would be represented by analyzing the two indices NDVI and BDI. Results showed the greatest increase in temperature within Upper-Hill of up to 3.96&#176C between the years 2015 and 2017. There was also an increase in impervious surfaces as indicated by NDVI and BDI within Upper-Hill and its surroundings. The linear regression results showed a negative correlation between LST and NDVI and a positive correlation with BDI, which is a better predictor of Land Surface Temperature than NDVI. Data sets were analyzed from Landsat imagery for the periods 1987, 2002, 2015 and 2017 to determine changes in land surface temperatures over a 30 year period and it’s relation to land cover changes using indices. Visual comparisons between Temperature differences between the years revealed that temperatures decreased around the urban areas. Minimum and maximum temperatures showed an increase of 1.6&#176C and 3.65&#176C respectively between 1987 and 2017. The comparisons between LST, NDVI and BDI show the results to be significantly different. The use of NDVI and BDI to study changes in land cover due to urbanization, reduces the time taken to manually classify moderate resolution satellite imagery.

Impact of Urbanisation on Land Use/Land Cover in Puducherry City, India

The change of land use plays a major role in the developmental activity of a developing country. Due to rapid growth of urbanisation and dramatic increasing population, the fertile agricultural land has been converted to built-up area with respect to the demand for housing requirement and to the need for basic infrastructure facilities. The quantum of open space and surface water bodies has also been encroached. There has been a rapid growth of population in Puducherry city from 3.48 million in 1991 to 5.44 million in 2011. Hence the conservation of natural resources becomes one of the major challenges especially in small and medium town. This study was conducted to assess the effect of change on land use in urban agglomeration area of Puducherry city for the duration period from 1997 to 2017. There has been an increase in population in Puducherry city mainly attributed to higher scale of migration from adjoining rural areas and medium town for better education, job opportunities and quality life. Hence, it has been strongly recommended for stringent Development Control Regulations to quantify the urban sprawl and manage the impact of urbanisation of land use/land cover in Puducherry city.

Analyzing Urban Expansion and Spatial Growth Patterns in Barahathawa Municipality of Central Tarai Region, Nepal

The rapid transformation of rural settlements into municipalities in Ne­pal has brought significant changes in land use,and urban expansion and growth patterns mostly through the conversion of agricultural land into the built-up area.The issue is studied taking a case of the rapidly growing town,Barahathawa Municipality of Tarai Region of Sarlahi District.After the declaration of the municipality,several new roads have been opened and upgraded;and the municipality is well-connected to the national transportation network.After promulgated the Constitution of Nepal 2015 and functioning the elected local body,the municipality budget has been increased significantly as a result of increasing municipal investment in so­cio-economic and physical infrastructure development and environmental protection which has attracted people,goods,and services creating the zone of influence on the municipality.One of the changes found in the munici­pality is the increasing built-up area and expansion of urban growth through the decreasing agricultural land.Urban growth has been observed taking place around the Barahathawa Bazaar and main roadsides.The built-up area in Barahathawa municipality has remarkably increased by 183percent with the decrease of shrub and agricultural land within 10 years.Implica­tions of such spatial and temporal dynamics have been a core issue of urban planning in most of the newly declared municipalities in Nepal.

城市人工浅水湖泊底栖动物群落结构及影响因素分析

探讨梅溪湖底栖动物群落结构及其影响因素,为城市人工湖泊水生态系统修复后的运营维护管理提供理论依据。2020-2021年在梅溪湖设置14个采样站位(敞水区7个,滨岸带7个),按季节开展底栖动物调查。研究结果表明,梅溪湖底栖动物种类达75种,滨岸带种类数高于敞水区。整个湖区全年优势种为米虾(Caridina sp.)、铜锈环棱螺(Bellamya aeruginosa)、椭圆萝卜螺(Radix swinhoei)、大脐圆扁螺(Hippeutis umbilicalis)、霍甫水丝蚓(Limnodri-lus hoffmeisteri)和沼虾(Macrobrachium sp.)。敞水区和滨岸带群落结构存在显著差异,除霍甫水丝蚓外,全年优势种是导致2个区域群落结构差异的主要分类单元。梅溪湖底栖动物现存量和多样性季节间无显著差异,但敞水区和滨岸带之间差异显著,滨岸带远高于敞水区,表明水生植物群落的构建有利于底栖动物种群的壮大和多样性的提高。CCA结果表明,氨氮(AN)和营养水平(TLI)对敞水区和滨岸带的底栖动物群落结构均有较大影响。CoIA分析结果显示,米虾、大脐圆扁螺、铜锈环棱螺、沼虾、椭圆萝卜螺等物种与环境因子存在较为密切的联系,这些物种可以作为梅溪湖水环境条件变化的指示种。合理控制梅溪湖底栖动物群落结构,并维持较高的多样性水平,可有效促进其生态系统的正常运转。

人民城市理念下景中村空间治理机制、困境与路径——以武汉东湖景区村落为例

人民城市的提出体现了中国之治在城市维度的新表达和城市治理理念的全新概括。城市景中村是我国城乡二元体制和风景名胜区保护制度下衍生出的一种特殊乡村形态,嵌入城市和风景区的空间之内,其特殊的空间组织、经济结构和社会关系凸显了景中村空间治理的复杂性和矛盾性,亟需厘清其治理和发展的现实困境,探索有效的治理路径。人民城市的景中村治理目标是建立各群体均衡的发展权、包容共享和公平公正的新型城乡关系。研究提出:1)人民城市空间治理机制体现了资本逻辑向人民逻辑转变的特征,内涵在于促进均衡的空间发展权力,最终实现属性、功能、组织的有机统一;2)景中村治理困境包括属性模糊、功能重构、组织无序三方面;3)景中村空间治理的实现路径包括治理规则创新、权属边界优化及行动机制建构,从而实现景中村的“生命共同体”。

Global mapping of urban built-up areas of year 2014 by combining MODIS multispectral data with VIIRS nighttime light data

An improved methodology for the extraction and mapping of urban built-up areas at a global scale is presented in this study.The Moderate Resolution Imaging Spectroradiometer(MODIS)-based multispectral data were combined with the Visible Infrared Imager Radiometer Suite(VIIRS)-based nighttime light(NTL)data for robust extraction and mapping of urban built-up areas.The MODIS-based newly proposed Urban Built-up Index(UBI)was combined with NTL data,and the resulting Enhanced UBI(EUBI)was used as a single master image for global extraction of urban built-up areas.Due to higher variation of the EUBI with respect to geographical regions,a region-specific threshold approach was used to extract urban built-up areas.This research provided 500-m-resolution global urban built-up map of year 2014.The resulted map was compared with three existing moderate-resolution global maps and one high-resolution map in the United States.The comparative analysis demonstrated finer details of the urban built-up cover estimated by the resultant map.

白洋淀上游流经城区前后细菌群落结构和功能与环境因子的关联研究

细菌群落作为水生态环境的重要组成部分,其结构和功能研究可为水生态环境污染监测与治理提供技术支撑。通过对流经城区白洋淀上游河流细菌群落的高通量测序和环境因子的监测,分析城市环境因素对白洋淀上游水质的影响,并深入探究细菌群落功能与污染物动态变化的关系。结果表明,城市环境对白洋淀上游生态环境的影响较大,上、中、下游的水质等级差异显著。城区中汇入的各类污染物不仅影响细菌群落结构,使得污染严重流域高丰度的细菌种群减少和细菌群落多样性增加;还与细菌群落的硝酸盐和磷酸盐代谢功能密切相关。同时,河流虽汇集了城区的各类污染物,但下游的细菌群落结构和部分氮、磷代谢功能均有恢复为上游水平的趋势。此外,高丰度的黄杆菌属(Flavobacterium)受各类菌群和污染物的抑制作用较大,但验证其与NO-3-N污染物具有较强的相关性。对白洋淀上游流经城区前后细菌群落结构和功能与环境因子动态变化的关联研究,为白洋淀流域生态环境保护与污染治理提供理论依据。

Measuring the past 20 years of urban-rural land growth in flood-prone areas in the developed Taihu Lake watershed, China

There is growing interest in using the urban landscape for stormwater management studies, where land patterns and processes can be important controls for the sustainability of urban development and planning. This paper proposes an original index of Major Hazard Oriented Level （MHOL） and investigates the structure distribution, driving factors, and controlling suggestions of urban-rural land growth in flood-prone areas in the Taihu Lake watershed, China. The MHOL of incremental urban-rural land increased from M 31.51 during the years 1985-1995 to M 38.37 during the years 1995-2010 （M for medium structure distribution, and the number for high-hazard value）. The index shows that urban-rnraI land was distributed uniformly in flood hazard levels and tended to move rapidly to high-hazard areas, where 72.68% of incremental urban-rural land was aggregated maximally in new urban districts along the Huning traffic line and the Yangtze River. Thus, the current accelerating growth of new urban districts could account for the ampliative exposure to high-hazard areas. New districts are driven by the powerful link between land financial benefits and political achievements for local governments and the past unsustainable process of ＂single objective＂ oriented planning. The correlation categorical analysis of the current development intensity and carrying capacity of hydrological ecosystems for sub-basins was used to determine four types of development areas and provide decision makers with indications on the future watershed- scale subdivision of Major Function Oriented Zoning implemented by the Chinese government.

滇池流域城镇区河流底栖动物群落结构及受干扰状况研究

研究城镇区域底栖动物群落结构特征及受干扰状况,对修复城市河流生态系统具有指示意义。以滇池流域为研究对象,基于2021年8月的底栖动物数据,采用优势度指数、生物多样性指数及丰度/生物量比较(ABC)曲线探究了底栖动物群落结构及受干扰状况。研究结果表明:①共鉴定出底栖动物39种,属于3门5纲,以节肢动物门为主,占物种总数的48.7%,水丝蚓属(Limnodrilus sp.)、摇蚊属(Chironomus sp.)等污染指示种为主要优势种。②多样性指数分析表明,流域生物多样性整体较低,Shannon-Weaver多样性指数、Margalef丰富度指数在各样点的差异较大,而Pielou均匀度指数各点差异较小。③ABC曲线分析表明,城镇区群落结构干扰程度总体为中度干扰并呈现出一定的空间差异,各河流按干扰程度可以划分为三类,一类为无干扰河流,占比25.0%;一类为轻度干扰河流,占比66.7%;一类为中度干扰,占比8.3%。④本研究结果可为滇池流域城镇区域河流的生态保护提供科学依据,下一步应结合相关环境数据,深入了解各环境类型与底栖动物群落结构的相关关系。

基于SolVES模型的东湖风景区社会价值评估及提升策略

城市湖泊型风景区具有良好的生态系统服务社会价值,是城市规划关注的热点。对当前的城市湖泊型风景区,少有从生态系统服务社会价值方面进行评估和研究。以武汉东湖风景区为例,通过SolVES模型对其生态系统服务社会价值及其影响因素进行评估,结果表明:游客对武汉东湖风景区美学价值、生命可持续价值、生物多样性价值、科研教育价值和康养价值评价较高;美学价值、康养价值和科研教育价值主要集中在磨山、听涛及落雁景区的主要旅游景点,生物多样性和生命可持续价值在各景区广泛分布;水体、植被覆盖度、公共设施、旅游景点、科教文化设施、交通设施的建设会影响游客对社会价值的偏好。根据研究结果对武汉东湖风景区生态系统服务社会价值提出了提升策略。

基于新城市主义的滨水片区规划设计研究——以芜湖凤鸣湖片区为例

滨水片区是生态系统和城市发展的重要组成部分,承载着激发内生活力、彰显地域特征、提升功能品质的重要责任。引导城市逐步提升滨水空间品质,打造具有复合多元、开合有致、水城联动、生态文明的优质滨水片区,体现了对滨水片区规划设计的新要求和新使命。文章基于新城市主义理论,通过对滨水片区现状问题的深入分析,提出重塑地块多元功能、优化内外交通组织、营造现代公共生活、转化自然资源优势的设计策略。同时,以凤鸣湖片区为典型案例,提出相应的设计方案,并对闲置衰败滨水片区的更新实践进行了探索,以期为滨水片区的规划设计提供一定的借鉴。

Underground space use of urban built-up areas in the central city of Nanjing:Insight based on a dynamic population distribution

With the expansion of cities and the emergence of various urban problems,urban underground space has been developed as a solution.In China’s urban transition context,there is a need for the development of underground space in urban built-up areas.In this casestudy of the central city of Nanjing,we used spatial analysis and statistical methods to characterize the underground space use of urban built-up areas from a dynamic spatiotemporal perspective.We first analyzed the relationship between the population distribution and the underground space use of the central city of Nanjing based on a Baidu heat map,which can reflect the real-time population distribution,and then,we explored the spatiotemporal characteristics and spatial structure of the underground space use in urban built-up areas.The analysis results provide a reference for planning to improve and optimize the layout of underground space in the central city of Nanjing and,more generally,for the stock-type planning of underground space in urban built-up areas.

Chinese City Size Ranking: A Comparative Study of the Urban Built-Up Area Based on Remote Sensing Data

Without a clear and unified definition of the urban built-up area, many city rankings by area are inconsistent, giving rise to confusion among the general public and even scholars. This paper summarizes various definitions of the urban built-up area and proposes three definition methods: all urban built-up areas in a municipal administrative area, concentrated contiguous built-up areas, and urban built-up areas in central cities. From the latest Landsat 8 satellite images, the paper obtains the data of urban built-up area in some of China’s big cities and makes a comparative study between the results of the urban built-up areas by the three definition methods and three other common statistical data. It finds that neither the area data nor the ranking is consistent. Finally, it further explores what causes differences in rankings and gives some advice for improving the definition of the urban built-up area.

2001年以来环洞庭湖区经济城镇化与人口城镇化进程的对比研究

以城镇人口占总人口的比重为人口城镇化的指标,以第二三产业增加值占GDP的比重为经济城镇化的指标,以历年统计数据为基础,围绕经济城镇化与人口城镇化的关系,利用EXCEL、SPSS、MAPGIS等软件,对2001年以来环洞庭湖区人口城镇化和经济城镇化进程进行了时间序列和空间序列的定量分析。从时间序列的对比来看,2001年以来,环洞庭湖区城镇化进程加快,但经济城镇化对人口城镇化的带动效率明显低于湖北、湖南和全国平均水平,使得人口城镇化滞后的程度在2007年后明显加剧;从空间序列的分析来看,湖区人口城镇化和经济城镇化水平呈现出核心区低,边缘区高,外围区低的同心带状结构,但人口城镇化最快的是边缘区域,而经济城镇化进程已由边缘区域向核心区域拓展。

基于“湖泊效应”的城市经济影响区空间分异模型及应用——以环鄱阳湖区为例

基于"湖泊效应"假设与城市空间结构理论,提出了湖泊影响周围城市经济的理论模型,并以环鄱阳湖区为例进行实证分析。研究显示,在鄱阳湖影响下,环鄱阳湖区城市分布密度和交通网络密度都随距湖距离变化而呈现出先逐渐增大继而逐渐减小的趋势,但随距离进一步增加,城市分布密度和交通网络密度又呈增大趋势,由此根据极值原理和专题属性将环鄱阳湖区划分为3个城市经济影响区。可见,该模型不仅可以从理论上解释湖泊如何影响周围城市经济区空间分异,而且可以提供一个定量分析模型加以推广。