5 research outputs found

    Time-Series Satellite Imagery Demonstrates the Progressive Failure of a City Master Plan to Control Urbanization in Abuja, Nigeria

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    Urbanization is a global phenomenon, but its negative effects are most pronounced in developing countries. While much urbanization in the global South is unplanned, there have been occasional attempts at strategic, large-scale urban planning. One example is Abuja, Nigeria, a new city with origins in a 1970s Master Plan. Here, we use multi-temporal remote sensing to investigate four decades of urbanization in Abuja, showing the extent to which urban development has matched original intentions. Seven Landsat images from 1975 to 2014 were selected to correspond with Master Plan milestones and turning points in Nigeria’s socio-political development. Land cover classification and change detection results show built-up land increasing rapidly, from 1,167 ha in 1975 to 18,623 ha in 2014, mostly converted from grassland, often via a pioneer bare soil class. Comparing image analysis against the Master Plan shows that, in the early years, Abuja’s development matched broad planning intentions fairly closely. Later, though, unplanned development proliferated, and the city’s resemblance to the Master Plan diminished progressively. Level of adherence to the Master Plan varied widely according to the system of government. Notably, after long-term military rule was replaced by a democratic government around the turn of the millennium, unplanned development increased sharply

    A configurational morphogenesis of incremental urbanism: A comparative study of the access network transformations in informal settlements

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    The morphologies of informal settlements constantly change as they undergo processes of incremental adaptations and transformations in relation to emerging circumstances. One of the ways to explore the underlying morphogenic processes governing such adaptations and transformations is to study the morphogenesis of informal settlement. Informal settlements can tell the story of how access networks evolve through incremental processes of change as they generally emerge and where possible become consolidated through forms of adaptations and transformations. Adopting a comparative case study research design approach, this paper explores the incremental transformations of access networks across three emerging settlements located in proximity to Abuja in Nigeria. These settlements are comparatively mapped using historic satellite images illustrating eight temporal stages between 2007 and 2021. Space Syntax is used as an analytical method to study the configurational morphogenesis of the access network with a focus on the measures of connectivity, betweenness, closeness, and intelligibility. The study shows how the flexibility of the early stages of development provides opportunities for the formation of what might be considered irregular elements in the access network. The research findings also suggest that the access network becomes less intelligible as it evolves. The locations of the main local cores of the access networks are found to remain relatively unchanged and somewhat fixed as emerging local cores come about in the newly developed areas. The spatial circumstances of the studied settlements are also found to have impacts on how the incremental adaptations and transformations generate new elements as part of the access networks. The findings of this study can inform the ways the built environment professions can engage with processes of incremental transformation by providing a better understanding of configurational morphogenesis in the context of informal urbanism

    Time-Series Satellite Imagery Demonstrates the Progressive Failure of a City Master Plan to Control Urbanization in Abuja, Nigeria

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    Abstract Urbanization is a global phenomenon, but its negative effects are most pronounced in developing countries. While much urbanization in the global South is unplanned, there have been occasional attempts at strategic, large-scale urban planning. One example is Abuja, Nigeria, a new city with origins in a 1970s Master Plan. Here, we use multi-temporal remote sensing to investigate four decades of urbanization in Abuja, showing the extent to which urban development has matched original intentions. Seven Landsat images from 1975 to 2014 were selected to correspond with Master Plan milestones and turning points in Nigeria’s socio-political development. Land cover classification and change detection results show built-up land increasing rapidly, from 1,167 ha in 1975 to 18,623 ha in 2014, mostly converted from grassland, often via a pioneer bare soil class. Comparing image analysis against the Master Plan shows that, in the early years, Abuja’s development matched broad planning intentions fairly closely.  Later, though, unplanned development proliferated, and the city’s resemblance to the Master Plan diminished progressively. Level of adherence to the Master Plan varied widely according to the system of government. Notably, after long-term military rule was replaced by a democratic government around the turn of the millennium, unplanned development increased sharply. </p
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