Evaluation of Spatio-Temporal Dynamics of Urban Sprawl in Osogbo, Nigeria using Satellite Imagery & GIS TechniquesDownload PDF
The sprawling nature of urban development on the fringe areas of big cities in developing countries particularly Nigeria has received much attention to the neglect of rapidly growing medium-sized cities despite the recent observation that African cities with less than 500, 000 inhabitants are absorbing two-third of all urban population growth. It has been argued that to understand the impact of new urbanization on the environment and people, these processes need to be examined in medium and small cities rather than restricting our inquiries to the large and mega-cities. This study assesses the trends and spatial patterns of urban sprawl in Osogbo between 1962 and 2011 with a view to generating base line geo-spatial information that may be used for effective and efficient urban planning and development policies.
The study employed Aerial Photos, Satellite Imageries and population Census data to achieve the purpose of the study. Digital image techniques were utilized in the processing of the images, statistical tools of GIS technologies, land use development index, land consumption rate index and land absorption coefficient index were used to analyze the data on temporal basis. Overlay operation was performed to integrate the urban land use to reveal the trends in the urban development over the study period. The emerging sprawling growth was further investigated by quantitatively mapping the metrics of manifestations using Erdas Imagine 9.1 and Arc GIS 9.3 Software. The results showed that urban sprawl in Osogbo was at a rate of 4.9Km2 per annum, indicating that the city which was 3.95Km2 in 1962 had increased to 241.79Km2 by size in 2011. Also, the pattern of sprawling was linear, leapfrogged and scattered along the major transport arteries thus, reflecting a star-shaped pattern. The study therefore advocates integration of the on-going urban renewal programme in Osun State into a consciously evolved digital master plan and set up a task force to enforce compliance. This can be strengthened by institutionalizing the recently adopted Geographic Information System (GIS) to evaluate, monitor and manage land development in the peri-urban areas of the city.
Keywords: Urban sprawl, Medium-sized city, GIS, Satellite imageries, Digital image techniques, Land use planning,
Geo-spatial information, Urban renewal.