Modelling and simulating urban expansion in Africa

非洲城市扩张建模和模拟

• 批准号: ES/W010046/1
• 负责人: Felix Seberh Kamusu Agyemang
• 金额: $ 28.88万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=ES%2FW010046%2F1
• 关键词: Modelling; simulating; urban; expansion; Africa

I will address an important gap in quantitative urban research by developing an openly accessible model for predicting patterns of spatial expansion in African cities. According to UN estimates, Africa's cities will house almost one billion additional people over the next 30 years (UN, 2018). Much of this increase will occur in informal settlements. Predicting geographic patterns of urban expansion is crucial for planners and policy makers seeking to improve urban living conditions while minimising the impacts of urban growth on energy consumption, pollution and ultimately climate change. Openly accessible global urban models that are sensitive to local conditions provide useful decision support tools for effective urban and regional planning.In this project, I will pursue four main objectives: (1) Develop an urban expansion model for African cities that can be parameterised to account for the diverse socioeconomic and regulatory conditions that underpin processes of urban development on the continent; (2) Validate the model in a range of primate and secondary cities across the continent; (3) Make predictions regarding the likely locations and legal status of new residential developments in a large sample of African cities; and (4) Disseminate the model to academics and practitioners through open access publications, an interactive website for the model, and training local planners and African researchers on how to use and modify the model to suit their needs.Achieving these objectives will make a significant contribution to the field of urban analytics and city science by addressing the persistent 'Western bias' in urban modelling. The most popular urban expansion models are not well-suited to contexts of 'informal urbanisation'. Further, existing urban models are poorly validated in informal contexts. For example, recent global projections of future urban expansion employ SLEUTH, a popular urban model based on a geophysical simulation approach. However, SLEUTH, as with other urban models that employ this simulation approach, does not model the social processes and institutional dynamics that generate the geographical patterns we observe. While SLEUTH's performance at a coarser regional scale is generally good, it does not perform particularly well in capturing local urban growth patterns. My research has shown that SLEUTH explains less than a fifth of the built-up expansion observed in Accra - a fast-growing city in West Africa experiencing informal urbanization - from 2000 to 2010. By contrast, TI-City, a model I developed to predict patterns of urban expansion in Accra explains up to 65 percent of the observed built-up expansion in the city over a decade. Unlike SLEUTH, TI-City accounts for the institutional and socioeconomic factors that shape decisions of households and developers by combining an agent-based model with a geophysical simulation approach. While the model is promising, it was developed based on urban expansion processes in Accra, and it is not a yet general model of the African city.Given that roughly 40 percent of future population growth will be absorbed by African cities, the shortcomings of the urban models matter. To improve current and future decision making about planning and resource allocation in Africa, there is the need for a new general urban expansion model, which accounts for the diverse socioeconomic conditions and regulatory contexts that shape urban development across the continent.By developing a general urban expansion model for African cities, this project will provide an openly accessible decision support tool for promoting effective urban planning and resource allocations thereby improving urban living conditions across the continent. The development of an interactive website, training of local planners, and publication of academic papers will help maximize the benefits of this project.

我将通过开发一个可公开访问的模型来预测非洲城市的空间扩展模式，从而解决定量城市研究中的一个重要空白。根据联合国的估计，非洲的城市将在未来30年内容纳近10亿人（联合国，2018年）。其中大部分增长将发生在非正规住区。预测城市扩张的地理模式对于寻求改善城市生活条件的规划者和政策制定者至关重要，同时最大限度地减少城市增长对能源消耗，污染和最终气候变化的影响。开放获取的全球城市模型对当地条件敏感，为有效的城市和区域规划提供了有用的决策支持工具。在这个项目中，我将追求四个主要目标：（1）为非洲城市开发一个城市扩展模型，该模型可以参数化，以说明支撑非洲大陆城市发展进程的各种社会经济和监管条件;（2）在整个非洲大陆的一系列主要城市和二级城市中推广该模型;（3）在大量非洲城市样本中对新住宅开发的可能位置和法律的地位进行预测;以及（4）通过开放获取出版物、模型的交互式网站，培训当地规划人员和非洲研究人员如何使用和修改模型以满足他们的需求。实现这些目标将通过解决城市建模中持续存在的“西方偏见”，为城市分析和城市科学领域做出重大贡献。最流行的城市扩张模式并不适合“非正式城市化”的背景。此外，现有的城市模式在非正规环境中的有效性很差。例如，最近对未来城市扩展的全球预测采用了SLEUTH，这是一种基于地球物理模拟方法的流行城市模型。然而，SLEUTH，与其他采用这种模拟方法的城市模型一样，并没有模拟产生我们观察到的地理模式的社会过程和制度动态。虽然SLEUTH的表现在一个粗略的区域规模一般是好的，它并没有表现得特别好，在捕捉当地的城市增长模式。我的研究表明，在阿克拉--西非一个经历非正式城市化的快速发展城市--从2000年到2010年观察到的建筑扩张中，SLEUTH解释的不到五分之一。相比之下，我开发的预测阿克拉城市扩张模式的TI-City模型解释了10年来该市65%的建筑扩张。与SLEUTH不同的是，TI-City通过将基于代理的模型与地球物理模拟方法相结合，考虑了影响家庭和开发商决策的制度和社会经济因素。虽然这个模型很有前景，但它是根据阿克拉的城市扩张过程开发的，还不是非洲城市的通用模型。考虑到未来大约40%的人口增长将被非洲城市吸收，城市模型的缺陷很重要。为了改善非洲当前和未来的规划和资源分配决策，需要一个新的城市总体扩张模式，该模式应考虑到影响整个非洲大陆城市发展的各种社会经济条件和监管背景。该项目将提供一个可公开获取的决策支持工具，以促进有效的城市规划和资源分配，从而改善整个非洲大陆的城市生活条件。开发一个互动网站、培训当地规划人员和出版学术论文将有助于最大限度地发挥这一项目的效益。