scholarly journals HOW TO CLASSIFY THE URBAN AREA? A PERSPECTIVE OF MULTI-CRITERIA APPROACH IN THE CONTEXT OF HYPER-DIVERSITY IN SETTLEMENTS IN GHANA

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
John E. K. AKUBIA ◽  
Paul W. K. YANKSON

Ghana is experiencing high population growth, rapid urbanization and a constantly accelerating growth of urban areas. Yet, the accurate delineation of urban settlements remains a major challenge faced by urbanists. While emergent urban settlements are being characterized by highly-diverse, heterogeneous, and multiplicity of features, the need to rethink how best to classify new urban growth areas, beyond the commonly used population threshold of ≥ 5000 inhabitants, is becoming increasingly inadequate. Thus, this paper proposes a multi-criteria approach, drawing on the concept of ‘hyper-diversity’. Eight key dimensions – urban form, built-up extent, socio-economic functions, land-use dynamics, occupational structure, governance structure and population size – were identified as a guide to the delineation of new urban settlements. Inferring these dimensions requires accurate spatial and statistical data on prevailing the land-use dynamics. Thus, the paper argues that analyzing satellite-based remote sensing and groundtruth-gathered data may provide standardized and timely information on the aforementioned dimensions. Applying this multi-dimensional approach may be useful for Ghana and similar countries where there is a lack of regular mapping of urban areas.

2020 ◽  
Vol 13 (4) ◽  
pp. 224
Author(s):  
Fombe Lawrence F. ◽  
Acha Mildred E.

Worldwide urban areas are having increasing influence over the surrounding landscape. Peri-urban regions of the world are facing challenges which results from sprawl with increasing problems of social segregation, wasted land and greater distance to work. This study seeks to examine the trends in land use dynamics, urban sprawl and associated development implications in the Bamenda Municipalities from 1996 to 2018. The study made use of the survey, historical and correlational research designs. The purposive and snowball techniques were used to collect data. Spatiotemporal analyses were carried out on Landsat Images for 1996, 2008, and 2018 obtained from Earth Explorer, Erdas Image 2014 and changes detected from the maps digitized. The SPSS version 21 and MS Excel 2016 were used to analyze quantitative and qualitative data. The former employed the Pearson correlation analysis. Analysis of land use/land cover change detection reveals that built-up area has increased significantly from 1996 to 2018 at the detriment of forest, wetland and agricultural land at different rates within each municipality. These changes have led to invasion of risk zones, high land values, uncoordinated, uncontrolled and unplanned urban growth. The study suggests that proactive planning, use of GIS to monitor land use activities, effective implementation of existing town planning norms and building regulations, are invaluable strategies to sustainably manage urban growth in Bamenda.


2018 ◽  
Vol 10 (11) ◽  
pp. 4287 ◽  
Author(s):  
Yantao Xi ◽  
Nguyen Thinh ◽  
Cheng Li

Rapid urbanization has dramatically spurred economic development since the 1980s, especially in China, but has had negative impacts on natural resources since it is an irreversible process. Thus, timely monitoring and quantitative analysis of the changes in land use over time and identification of landscape pattern variation related to growth modes in different periods are essential. This study aimed to inspect spatiotemporal characteristics of landscape pattern responses to land use changes in Xuzhou, China durfing the period of 1985–2015. In this context, we propose a new spectral index, called the Normalized Difference Enhanced Urban Index (NDEUI), which combines Nighttime light from the Defense Meteorological Satellite Program/Operational Linescan System with annual maximum Enhanced Vegetation Index to reduce the detection confusion between urban areas and barren land. The NDEUI-assisted random forests algorithm was implemented to obtain the land use/land cover maps of Xuzhou in 1985, 1995, 2005, and 2015, respectively. Four different periods (1985–1995, 1995–2005, 2005–2015, and 1985–2015) were chosen for the change analysis of land use and landscape patterns. The results indicate that the urban area has increased by about 30.65%, 10.54%, 68.77%, and 143.75% during the four periods at the main expense of agricultural land, respectively. The spatial trend maps revealed that continuous transition from other land use types into urban land has occurred in a dual-core development mode throughout the urbanization process. We quantified the patch complexity, aggregation, connectivity, and diversity of the landscape, employing a number of landscape metrics to represent the changes in landscape patterns at both the class and landscape levels. The results show that with respect to the four aspects of landscape patterns, there were considerable differences among the four years, mainly owing to the increasing dominance of urbanized land. Spatiotemporal variation in landscape patterns was examined based on 900 × 900 m sub-grids. Combined with the land use changes and spatiotemporal variations in landscape patterns, urban growth mainly occurred in a leapfrog mode along both sides of the roads during the period of 1985 to 1995, and then shifted into edge-expansion mode during the period of 1995 to 2005, and the edge-expansion and leapfrog modes coexisted in the period from 2005 to 2015. The high value spatiotemporal information generated using remote sensing and geographic information system in this study could assist urban planners and policymakers to better understand urban dynamics and evaluate their spatiotemporal and environmental impacts at the local level to enable sustainable urban planning in the future.


BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Mariëtte Pretorius ◽  
Wanda Markotter ◽  
Mark Keith

Abstract Background Modification and destruction of natural habitats are bringing previously unencountered animal populations into contact with humans, with bats considered important zoonotic transmission vectors. Caves and cave-dwelling bats are under-represented in conservation plans. In South Africa, at least two cavernicolous species are of interest as potential zoonotic hosts: the Natal long-fingered bat Miniopterus natalensis and the Egyptian fruit bat Rousettus aegyptiacus. Little information is available about the anthropogenic pressures these species face around important roost sites. Both bats are numerous and widespread throughout the country; land-use changes and urban expansions are a rising concern for both conservation and increased bat-human contact. Results Our study addressed this shortfall by determining the extent of land-cover change around 47 roosts between 2014 and 2018 using existing land cover datasets. We determined the land-cover composition around important roost sites (including maternity, hibernacula and co-roosts), distances to urban settlements and assessed the current protection levels of roost localities. We detected an overall 4% decrease in natural woody vegetation (trees) within 5 km buffer zones of all roost sites, with a 10% decrease detected at co-roost sites alone. Agricultural land cover increased the most near roost sites, followed by plantations and urban land-cover. Overall, roosts were located 4.15 ± 0.91 km from urban settlements in 2018, the distances decreasing as urban areas expand. According to the South African National Biodiversity Institute Ecosystem Threat Status assessment, 72% of roosts fall outside of well-protected ecosystems. Conclusions The current lack of regulatory protection of cavernicolous bats and their roosts, increasing anthropogenic expansions and proximity to human settlements raises concerns about increased human-bat contact. Furthermore, uncontrolled roost visitation and vandalism are increasing, contributing to bat health risks and population declines, though the extent of roosts affected is yet to be quantified. In an era where pandemics are predicted to become more frequent and severe due to land-use change, our research is an urgent call for the formal protection of bat-inhabited caves to safeguard both bats and humans.


Author(s):  
Omar M. Galal

Urban settlements are recognized in literature to be a significant energy consumer. Among the primary contributors of such consumption is the transportation system. Recent literature that discusses the relation between energy efficient mobility and urban form has been continually branching and growing. However, as it grew, it becomes more specialized, less self-conscious, and to some extent contradicting. After adopting Conzen's approach to urban morphology, this chapter discusses through an argumentative review the relationship between energy efficient mobility and buildings density, land use, and streets networks. In addition to providing a snapshot to critical studies in the last three decades, two arguments are refuted. First, the residents' behavior resulting from socio-economic factors or individuals' choice has more impact than urban morphology characteristics on energy-efficient mobility. Second, morphological characteristics of urban settlements that lead to energy efficient mobility do not vary with the variation of context.


2021 ◽  
Author(s):  
Jessica Page ◽  
Haozhi Pan ◽  
Zahra Kalantari

<p>Globally, urban areas contribute significantly to the emissions of the greenhouse gases (GHGs) which are leading to anthropogenic climate change. To achieve long-term sustainable development goals, urban regions will need to grow and develop in such a way that they can both provide a good quality of life for all of their inhabitants, and also reduce and offset their GHG emissions to reach and maintain net-zero GHG emissions.</p><p>This work aims to further our understanding of the impact of urban form and growth on GHG emissions, to identify ways in which nature-based solutions (NBS) can be integrated into urban planning to help cities reach net zero emissions while continuing to grow sustainably. We will conduct a high-resolution (1x1km) spatial accounting and mapping of GHG emissions from selected urban anthropogenic activities (residential, commercial, transportation) for Stockholm, Sweden which includes those factors relevant to and impacted by urban form (such as density, land use pattern transportation networks, green spaces) to allow for the analysis of different types of city spatial patterns and planning decisions and their implications in GHG emissions. The results will be further expanded to cities across the European Union (EU) for comparison. Conclusions will be drawn about where and how NBS interventions should be used most effectively to reduce urban GHG emissions and facilitate sustainable city growth in the future.</p><p><strong>Keywords:</strong> Sustainable cities; Land-use; Greenhouse Gas Emissions; Nature-based Solutions</p>


2013 ◽  
Vol 16 (1) ◽  
pp. 114-129 ◽  
Author(s):  
Haijun Wang ◽  
Wenting Zhang ◽  
Song Hong ◽  
Yanhua Zhuang ◽  
Hongyan Lin ◽  
...  

Non-point source (NPS) pollution has become the major reason for water quality deterioration. Due to the differences in the generation and transportation mechanisms between urban areas and rural areas, different models are needed in rural and urban places. Since land use has been rapidly changing, it is difficult to define the study area as city or country absolutely and the complex NPS pollution in these urban–rural mixed places are difficult to evaluate using an urban or rural model. To address this issue, a fuzzy system-based approach of modeling complex NPS pollutant is proposed concerning the fuzziness of each land use and the ratio of belonging to an urban or rural place. The characteristic of land use, impact of city center and traffic condition were used to describe spatial membership of belonging to an urban or rural place. According to the spatial membership of belonging to an urban or rural place, the NPS distributions calculated by the urban model and rural model respectively were combined. To validate the method, Donghu Lake, which is undergoing rapid urbanization, was selected as the case study area. The results showed that the urban NPS pollutant load was significantly higher than that of the rural area. The land usage influenced the pollution more than other factors such as slope or precipitation. It also suggested that the impact of the urbanization process on water quality is noteworthy.


2016 ◽  
Vol 19 (2) ◽  
pp. 146-153
Author(s):  
Hoa Thanh Le ◽  
Chau Thi Phuong Nguyen

Urban morphology in urban studies is used to classify and manage the distribution of urban densities. In urban planning, it helps to identify the emerging problems and solve the disorder of urban functions as in the megacity of Ho Chi Minh City. Rapid urbanization has increased the development footprint with disordered densities of building footprint, incomplete infrastructure and urban - peripheral instability. And it, then, caused more flood problems to the city. This study was based on applying fractal geometry, GIS on large-scale maps for identifying residential density based on urban morphology. The land-use map and the building footprints map of 2010 were integrated in fractal geometry to analyze the distribution of urban areas by the large scale of GIS data. This study showed HCMC had problems on irrational development in residential densities areas; and uneven development of population and residential density between the urban areas. At block scale of land-use block, in urban center had highest densities of building footprints and population, then, the medium densities in developing districts and rural-sub-districts. With these densities, there was more flood in high density areas, as in urban center, and less flood in lower density areas, as in sub-urban areas. These problems may cause some limitations to development of social, commercial, industrial, and infrastructure in HCMC. City needs to have flood control and management for development of the city.


2022 ◽  
Vol 14 (1) ◽  
pp. 522
Author(s):  
Samith Madusanka ◽  
Chethika Abenayake ◽  
Amila Jayasinghe ◽  
Chaminda Perera

The purpose of this study was to evaluate the four-dimensional relationship between land use, accessibility, density, and surface runoff in urban areas. In contemporary literature, a series of studies have been conducted that extensively discuss the natural components associated with the surface runoff in urban areas. However, the dynamic and complex dimensions of the urban form, such as land use, accessibility, and density, are yet to be fully understood. In this study, a 4D diagram was utilized to identify relationships between dimensions, in addition to decision tree analysis, to explore the structural flow between selected variables. Furthermore, a structural equation modeling (SEM) approach was employed with the purpose of investigating the direct, indirect, and moderating effects on the targeted dependent variable, surface runoff. The results of the analysis reported a strong correlation between land use, accessibility, density, and surface runoff, with an R-squared value of 0.802, which indicates an acceptable model accuracy by the international standard. A positive relationship between the four dimensions was indicated by the higher accessibility; the higher density in terms of a higher floor space index (FSI), ground space index (GSI), and open space; the building height of the adjacent buildings; the higher diversity of the land use; and the higher surface runoff. Accordingly, the findings of the study offer policy implications in the fields of land use planning, zoning regulations and overall urban development planning towards achieving climate resilient cities.


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