Dynamics of Changes in Spatial Patterns of Built-Up Areas in Two Metropolitan Areas of Grand Lomé and Greater Accra (West Africa)

Urbanization and population growth in West Africa have significantly altered land use and land cover (LULC), raising environmental concerns. This study examines urban land use patterns in the District Autonome du Grand Lomé (DAGL) and Greater Accra Metropolitan Area (GAMA) from 1986 to 2023 and from 1991 to 2023, respectively, using geospatial techniques and the Google Earth Engine (GEE). Previous research has overlooked the complexity of land use patterns and the directional analysis of urban expansion, which are vital for understanding urbanization drivers. This study addresses these gaps by comparing the two metropolitan areas, revealing a dramatic decline in verdant landscapes, with forested areas in DAGL decreasing from 24% in 1986 to 3% by 2023, and from 34% in 1991 to 2% in GAMA. Grasslands also diminished significantly, while built-up areas expanded from 18% to 62% in DAGL and from 10% to 70% in GAMA. The Urban Expansion Intensity Index (UEII) indicates rapid urban growth, with DAGL at 1.19% and GAMA at 1.88%. Directional analyses reveal that urban expansion predominantly occurs toward the northwest in DAGL and both northeast and northwest in GAMA, highlighting the need for effective urban planning and land management to preserve natural landscapes amidst ongoing urbanization challenges.