Spatiotemporal Analysis of Urban Expansion and Agricultural Land Loss in the Lagos Megacity Region

The Lagos megacity region is experiencing one of the fastest urban expansion rates in Africa, with profound implications for food production capacity and agricultural land availability in South West Nigeria. This study conducts a spatiotemporal analysis of urban expansion patterns and quantifies agricultural land loss in a 60-kilometre radius around the Lagos urban core between 2010 and 2024, addressing a documented gap in long-term, sub-regional land transition evidence. Random Forest supervised classification applied to Landsat 8 and Sentinel-2 time-series data achieves an overall accuracy of 91.4 percent across six land cover classes. Landscape metrics including patch density, edge density, and mean patch size are computed at five-year intervals to characterise the changing urban morphology. Spatial regression modelling employing geographically weighted regression examines the influence of road accessibility, distance from Lagos Island, population density, and land value gradients on the intensity of urban encroachment into agricultural zones. Results indicate a net loss of 187,000 hectares of agricultural land to urban conversion over the study period, with the fastest agricultural land conversion rates occurring in Ogun and Oyo States along the Sagamu-Ibadan corridor. The geographically weighted regression reveals spatially non-stationary relationships between explanatory variables and conversion intensity, with road proximity being the strongest predictor in all sub-regions. Findings are communicated to the Lagos State Physical Planning Authority and the South West Regional Development Commission. Keywords: urban expansion, agricultural land loss, spatiotemporal analysis, Lagos, geographically weighted regression.