Urban Sprawl and Land Cover in Post-apartheid Johannesburg and the Gauteng City-Region, 1990–2018

2021 ◽  
pp. 097542532199797
Author(s):  
Samy Katumba ◽  
David Everatt
Keyword(s):  
Land Cover ◽  
Population Growth ◽  
Urban Sprawl ◽  
Urban Areas ◽  
High Speed ◽  
City Region ◽  
Ongoing Research ◽  
South Africans ◽  
Urban Edge ◽  
History Of

Johannesburg and the broader Gauteng City-Region in which it is located are considered to be the economic powerhouse of South Africa. This has led to massive population growth in the region, as well as severe inequality. Given South Africa’s history of racially excluding black South Africans from urban areas, ongoing research in this area has to analyse land cover and define ‘sprawl’ in a context where the technical language has politically loaded overtones. This article tries to understand the scale of informality within a broader examination of urbanization and sprawl. It concludes that in the absence of a formally adopted urban edge and under massive pressure from population growth (natural and via migration), formal dwellings (residential and economic) have grown unchecked, and informality is now growing at high speed and also largely without regulation or control. With no apparent political will to stop urban sprawl, both informal and formal covers are steadily pushing towards provincial borders, while densifying in Johannesburg in particular.

RELATIONSHIP BETWEEN POPULATION GROWTH WITH CHANGING LAND-USE PATTERN AND ENVIRONMENTAL CHANGES IN KOLKATA, WEST BENGAL

2021 ◽  
pp. 57-61
Author(s):  
Arunima Dasgupta
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Population Growth ◽  
Environmental Degradation ◽  
Urban Sprawl ◽  
West Bengal ◽  
Environmental Changes ◽  
Capital City ◽  
Special Focus ◽  
Rapid Urbanization

Given that urbanization is considered as one of the most signicant anthropogenic alteration of the overall environment, the present study attempts to understand spatial-temporal characteristics of urban population growth and its implications on land-use as well as understanding their relationship with environmental degradation with special focus on the Kolkata, the capital city of West Bengal. Urbanization is one of the major driving forces behind the development of today's land-use and land cover system. A large number of contemporary urbanization has been characterized as urban sprawl namely in an extensive form of land-use for urban uses that have environmentally detrimental effects. There are indications of Urban sprawl and city expansion in our Study Area of Kolkata indicating expansion of settlements and built-up area and thus causing environmental degradation in the city area. The process of urbanization always had signicant implications that can affect cumulative changes in demographic characteristics and/or transformation of the physical environment; unplanned, unsystematic and rapid urbanization can cause intense impacts on various environmental aspects, specically on land and air and water. A thorough understanding of the dynamic relationship between urbanization and its generated land-cover changes thus becomes completely essential for managing environmental changes and enabling sustainability of the environment and its resources.

scholarly journals Measuring and Predicting Long-Term Land Cover Changes in the Functional Urban Area of Budapest

2020 ◽  
Vol 12 (8) ◽  
pp. 3331
Author(s):  
József Lennert ◽  
Jenő Zsolt Farkas ◽  
András Donát Kovács ◽  
András Molnár ◽  
Rita Módos ◽  
...  
Keyword(s):  
Land Cover ◽  
Urban Area ◽  
Urban Sprawl ◽  
Urban Areas ◽  
Agricultural Land ◽  
Arable Land ◽  
Land Cover Changes ◽  
Research Findings ◽  
Nature And Society

The loss of farmland to urban use in peri-urban areas is a global phenomenon. Urban sprawl generates a decline in the availability of productive agricultural land around cities, causing versatile conflicts between nature and society and threatening the sustainability of urban agglomerations. This study aimed to uncover the spatial pattern of long-term (80 years) land cover changes in the functional urban area of Budapest, with special attention to the conversion of agricultural land. The paper is based on a unique methodology utilizing various data sources such as military-surveyed topographic maps from the 1950s, the CLC 90 from 1990, and the Urban Atlas from 2012. In addition, the multilayer perceptron (MLP) method was used to model land cover changes through 2040. The research findings showed that land conversion and the shrinkage of productive agricultural land around Budapest significantly intensified after the collapse of communism. The conversion of arable land to artificial surfaces increased, and by now, the traditional metropolitan food supply area around Budapest has nearly disappeared. The extent of forests and grasslands increased in the postsocialist period due to national afforestation programs and the demand of new suburbanites for recreational space. Urban sprawl and the conversion of agricultural land should be an essential issue during the upcoming E.U. Common Agricultural Policy (CAP) reforms.

scholarly journals Dynamics and forecasting of population growth and urban expansion in Srinagar City – A Geospatial Approach

2014 ◽  
Vol XL-8 ◽  
pp. 709-716 ◽  
Author(s):  
M. Farooq ◽  
M. Muslim
Keyword(s):  
Population Growth ◽  
Urban Sprawl ◽  
Urban Growth ◽  
Urban Areas ◽  
Geographical Information Systems ◽  
Urban Expansion ◽  
Geographical Information ◽  
Spatial And Temporal Variability ◽  
Jammu And Kashmir ◽  
Srinagar City

The urban areas of developing countries are densely populated and need the use of sophisticated monitoring systems, such as remote sensing and geographical information systems (GIS). The urban sprawl of a city is best understood by studying the dynamics of LULC change which can be easily generated by using sequential satellite images, required for the prediction of urban growth. Multivariate statistical techniques and regression models have been used to establish the relationship between the urban growth and its causative factors and for forecast of the population growth and urban expansion. In Srinagar city, one of the fastest growing metropolitan cities situated in Jammu and Kashmir State of India, sprawl is taking its toll on the natural resources at an alarming pace. The present study was carried over a period of 40 years (1971–2011), to understand the dynamics of spatial and temporal variability of urban sprawl. The results reveal that built-up area has increased by 585.08 % while as the population has increased by 214.75 %. The forecast showed an increase of 246.84 km<sup>2</sup> in built-up area which exceeds the overall carrying capacity of the city. The most common conversions were also evaluated.

scholarly journals Time-dependent methods to evaluate the effects of urban sprawl on groundwater quality: a synthesis

2017 ◽  
Author(s):  
Stefania Stevenazzi
Keyword(s):  
Population Growth ◽  
Groundwater Quality ◽  
Urban Sprawl ◽  
Urban Areas ◽  
Water Cycle ◽  
Groundwater Resources ◽  
Groundwater Vulnerability ◽  
Time Dependent ◽  
The European Union ◽  
Lombardy Region

Freshwater resources are threatened worldwide with unknown and unpredictable fate, due to non-stationarity and change of water cycle dynamics, and increasing demand resulting from population growth and economic expansion. Thus, practical actions, strategies and solutions are necessary to ensure the short-term and long-term provision of adequate, affordable, accessible and safe freshwater supply to meet the needs of the growing human population and ecosystems. Since the mid-1950s, Europe is experiencing the phenomenon of urban sprawl, characterized by an unplanned incremental urban development, no more tied with population growth (EEA 2006). Impacts of urban sprawl threaten both the natural and rural environments and the quality of life for people living in cities, with worsening of air quality, and surface- and groundwater quality and quantity. For the protection of groundwater, the European Union issued a series of Directives (Water Framework Directive, 2000/60/EC; Groundwater Directive, 2006/118/EC) that require member states to achieve a good chemical status of their groundwater bodies and the identification of areas where groundwater suffers increasing trends in contaminant concentrations. In order to cope with EU Directives, a time-dependent approach for groundwater vulnerability assessment is developed to account for both the recent status of groundwater contamination and its evolution in the Po Plain area of Lombardy Region (northern Italy). Such approach takes the advantages of a Bayesian spatial statistical method to assess groundwater vulnerability and satellite scatterometer data to delineate urban areas and monitor their evolution. The proposed approach can determine potential impacts of contamination events on groundwater quality, if policies are maintained at the status quo or if new measures are implemented for safeguarding groundwater resources.

Land Cover Analysis for Evapotranspiration Assessment in Catania Metropolitan Region

2013 ◽  
pp. 102-114 ◽  
Author(s):  
Paolo La Greca ◽  
Daniele La Rosa ◽  
Francesco Martinico ◽  
Riccardo Privitera
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Metropolitan Area ◽  
Urban Sprawl ◽  
Land Use Planning ◽  
Urban Areas ◽  
Metropolitan Region ◽  
Urban Region ◽  
Climate Change Effects ◽  
Mt Etna

Today, the contraction of green zones is a key issue for land use planning with relation to climate change effects on urban areas. Furthermore, the loss of evapotranspiring surfaces and vegetated soils is one of the main consequences of urban sprawl processes. The authors present the case of Catania metropolitan area, the 2nd most populated urban region in Sicily. In particular, three municipalities are analyzed, as they present the most relevant urban sprawl processes. Inside this complex “urban jam,” there are still large non urbanized spaces. These patches (cultivated and abandoned agriculture land and lava fields from Mt. Etna), deeply fragmented, are often left for future development. These areas are particularly important in the examined context, considering the lack of green spaces for ecological functions and leisure. This chapter focuses on land cover analysis based on land use maps and oriented to assess evapotranspiration degree of the different land uses. Land use categories have been geographically sampled, and eight land cover types have been extracted with GIS by photo interpretation of high resolution orthophotos. Other sets of geodatabases have been used, including vectorial/raster cartographies and field surveys. Results from this evapotranspiration assessment can be useful for addressing land use planning of non urbanized areas within a sprawled metropolitan area, identifying new forms of agriculture, leisure, and environment protection.

scholarly journals Population growth, land use and land cover transformations, and water quality nexus in the Upper Ganga River basin

2018 ◽  
Vol 22 (9) ◽  
pp. 4745-4770 ◽  
Author(s):  
Anoop Kumar Shukla ◽  
Chandra Shekhar Prasad Ojha ◽  
Ana Mijic ◽  
Wouter Buytaert ◽  
Shray Pathak ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Linear Regression ◽  
Land Cover ◽  
Population Growth ◽  
Multiple Linear Regression ◽  
River Basin ◽  
Urban Areas ◽  
Ganga River ◽  
Geographical Information

Abstract. The Upper Ganga River basin is socioeconomically the most important river basin in India and is highly stressed in terms of water resources due to uncontrolled land use and land cover (LULC) activities. This study presents a comprehensive set of analyses to evaluate the population growth, LULC transformations, and water quality nexus for sustainable development in this river basin. The study was conducted at two spatial scales: basin scale and district scale. First, population data were analyzed statistically to study demographic changes, followed by LULC change detection over the period of February–March 2001 to 2012 (Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data) using remote sensing and geographical information system (GIS) techniques. Trends and spatiotemporal variations in monthly water quality parameters, viz. biological oxygen demand (BOD), dissolved oxygen (DO, measured in percentage), fluoride (F), hardness (CaCO3), pH, total coliform bacteria and turbidity, were studied using the Mann–Kendall rank test and an overall index of pollution (OIP) developed specifically for this region, respectively. A relationship was deciphered between LULC classes and OIP using multivariate techniques, viz. Pearson's correlation and multiple linear regression. From the results, it was observed that population has increased in the river basin. Therefore, significant and characteristic LULC changes were observed. The river became polluted in both rural and urban areas. In rural areas, pollution is due to agricultural practices, mainly fertilizers, whereas in urban areas it is mainly contributed from domestic and industrial wastes. Water quality degradation has occurred in the river basin, and consequently the health status of the river has also changed from acceptable to slightly polluted in urban areas. Multiple linear regression models developed for the Upper Ganga River basin could successfully predict status of the water quality, i.e., OIP, using LULC classes.

The Population History of Asia

2019 ◽  
Author(s):  
Tim Dyson
Keyword(s):  
Population Growth ◽  
20Th Century ◽  
Urban Areas ◽  
Indian Subcontinent ◽  
Population Data ◽  
Population History ◽  
Resource Base ◽  
Demographic Transitions ◽  
Modern Times ◽  
History Of

When composed of hunter-gatherers, Asia’s population numbered perhaps 1–2 million. But the emergence of agriculture saw population growth, and it appears likely that by 1 CE the continent’s population exceeded 100 million. For China and Japan, there are data which shed light on their population histories during pre-modern times. Moreover, both countries experienced rapid demographic transitions in the 20th century—substantially limiting the associated extent of population growth. For the Indian subcontinent and Southeast Asia, there are almost no population data prior to the late 18th century, although what happened subsequently is better recorded. Both these diverse regions experienced fairly protracted modern demographic transitions and substantial population growth. West Asia’s population is thought to have been of similar size in 1900 as in 1 CE. During the 20th century, however, most countries in West Asia experienced late birth-rate declines and very substantial population growth. Throughout history, the level of urbanization in Asia has generally been extremely low. Nevertheless, the continent contained most of the world’s most populous cities, though that situation changed temporarily in the 19th and 20th centuries. That said, after 1950 mortality decline fueled urban growth. As a result, by 2020 Asia once again contained most of the world’s largest cities, and about half of the continent’s people lived in urban areas. The population history of Asia has generally involved very slow population growth. The main explanation has been that death rates were high, marriage was early and universal, fertility was uncontrolled, and so birth rates were high too. However, research has increasingly suggested that in some areas the levels of fertility and mortality which prevailed in pre-modern times are better described as “moderate” rather than “high.” Moreover, as in Europe, there were regulatory mechanisms which helped to maintain a degree of balance between human numbers and the resource base.

scholarly journals Measurement of 30-Year Urban Expansion Using Spatial Entropy in Changwon and Gimhae, Korea

2021 ◽  
Vol 13 (2) ◽  
pp. 632
Author(s):  
Ki Hwan Cho ◽  
Do-Hun Lee ◽  
Tae-Su Kim ◽  
Gab-Sue Jang
Keyword(s):  
Land Cover ◽  
Urban Sprawl ◽  
Urban Areas ◽  
Urban Expansion ◽  
Spatial Context ◽  
Concentric Ring ◽  
Common Boundary ◽  
Spatial Entropy ◽  
Two Cities ◽  
Land Cover Map

Entropy is widely used for measuring the degree of urban sprawl. However, despite the intense use of the entropy concept in urban sprawl, entropy’s spatial context has been largely ignored. In this study, we analyzed urban sprawl in Changwon and Gimhae cities, as they shared a common boundary but differed in their population growth and urban expansion. The land cover type, “urban and dry area,” was used to identify urban areas in the two cities, and a land cover map showed the areas of expansion in the 1980s, 1990s, 2000s, and 2010s. Different zoning schemes, namely concentric rings and regular partitioning, were applied. Shannon’s and Batty’s spatial entropy indices were used to measure urban sprawl. The results showed that concentric ring zoning was not suitable for measuring urban sprawl in a decentralized and polycentric city. Batty’s spatial entropy was less affected by the zoning scheme used and reflected the pattern of urban expansion more accurately. Urban sprawl, a phenomenon occurring within a spatial context, can be better understood by measuring spatial entropy with appropriate zoning schemes.

Multiple phase transitions investigated by high-speed TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 550-551
Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt
Keyword(s):  
Phase Transitions ◽  
High Speed ◽  
Short Exposure ◽  
Semiconductor Film ◽  
Time Resolved ◽  
Short Exposure Time ◽  
Multiple Phase ◽  
Model Substance ◽  
History Of ◽  
Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

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