Geography Research Works

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Browsing Geography Research Works by Subject "Africa"

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    Characterizing Small-Town Development Using Very High Resolution Imagery within Remote Rural Settings of Mozambique
    (MDPI, 2021-08-26) Chen, Dong; Loboda, Tatiana V.; Silva, Julie A.; Tonellato, Maria R.
    While remotely sensed images of various resolutions have been widely used in identifying changes in urban and peri-urban environments, only very high resolution (VHR) imagery is capable of providing the information needed for understanding the changes taking place in remote rural environments, due to the small footprints and low density of man-made structures in these settings. However, limited by data availability, mapping man-made structures and conducting subsequent change detections in remote areas are typically challenging and thus require a certain level of flexibility in algorithm design that takes into account the specific environmental and image conditions. In this study, we mapped all buildings and corrals for two remote villages in Mozambique based on two single-date VHR images that were taken in 2004 and 2012, respectively. Our algorithm takes advantage of the presence of shadows and, through a fusion of both spectra- and object-based analysis techniques, is able to differentiate buildings with metal and thatch roofs with high accuracy (overall accuracy of 86% and 94% for 2004 and 2012, respectively). The comparison of the mapping results between 2004 and 2012 reveals multiple lines of evidence suggesting that both villages, while differing in many aspects, have experienced substantial increases in the economic status. As a case study, our project demonstrates the capability of a coupling of VHR imagery with locally adjusted classification algorithms to infer the economic development of small, remote rural settlements.
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    Considerations for AI-EO for agriculture in Sub-Saharan Africa
    (Institute of Physics, 2023-03-24) Nakalembe, Catherine; Kerner, Hannah
    Adapting to and mitigating climate change while addressing food insecurity are top priorities in SubSaharan Africa that require technologies to improve rural livelihoods with minimal environmental costs [1]. Artificial intelligence (AI) offers great promise for climate-smart solutions that improve food security outcomes. While precision agriculture is often the foremost use case for AI in agriculture (e.g. automation of farm equipment or nutrient application), precision agriculture is out of reach for most African farmers due to the required capital and infrastructure. AI solutions using satellite Earth observations (EOs), which we call AI-EO, are more accessible in the near term. EO enables agricultural analyses and insights at global scales, and many datasets are freely available, making EO-based solutions affordable [2]. AI-EO-derived products such as crop type maps and yield estimates are necessary to forecast food production surpluses or deficits, inform trade, and aid decisions. These products can support policies that accelerate the design and adoption of climate-smart agriculture and impact farmer livelihoods by increasing access to actionable early warning, risk financing or insurance [3], farm inputs, markets, and costreducing interventions [2, 4]. Despite their promise, AI-EO solutions for agriculture in Africa are still limited. Most techniques are not generalizable across heterogeneous landscapes. In this paper, we describe the principal sub-fields of research in AI-EO for agriculture in Africa and discuss examples and limitations of existing work. We also propose ten considerations for future work to help increase the impact of AI-EO research in Africa.
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    Fire Regions as Environmental Niches: A New Paradigm to Define Potential Fire Regimes in Africa and Australia
    (Wiley, 2022-07-07) Zubkova, M.; Boschetti, L.; Abatzoglou, J. T.; Giglio, L.
    Despite the widespread use of the “fire regime” concept for describing spatial and temporal patterns and ecosystem impacts of fire, this concept lacks an unambiguous, quantitative definition. By adopting from the ecological literature the concept of climate niche, that is, the environmental conditions that allow a specie to exist, we propose a new framework where variables that promote fuel accumulation and desiccation were used to define the environmental space at the continental level, later divided into regions (“fire regions”) with distinct fire potential. Our proposed approach emphasizes climate controls on fire patterns, distinct from the controls that humans exert on observed fire activity. By applying this framework, we identified nine fire regions in Africa and eight in Australia, distinguishing differences in fire patterns between continents as a result of changes in environmental gradient. Not only did we find that fire size and intensity varied significantly between continents, but biomes at a continental level were also found to be heterogeneous in terms of fire frequency, size, and intensity. For example, within African tropical savannas, the total annual rainfall and tree cover change drastically North and South of the equator, resulting in fire regions with significantly different fire characteristics. Meanwhile, in Australia, a strong gradient of annual temperature and precipitation seasonality was observed within tropical savannas and xeric shrublands, which was recognized by dividing those biomes into five regions with statistically different fire activity. Additionally, human presence led to some heterogeneity of fire patterns within delineated fire regions that also varied across biomes.