Monitoring and Modelling of Urban Sprawl in Osogbo Metropolis, using GIS and Remote Sensing

Abstract

 Rapid urbanization in the world is a major and concerning issue, particularly in emerging nations such as Nigeria, and this has resulted in various environmental issues which urban sprawl is one of. The existing built-up area, land and housing policies, accessible empty land area, existing number of households, demographic parameters, and the nature of the economy, among other factors, all influence urban area expansion. Using Landsat imagery, this study assessed urban sprawl in Osogbo Metropolis, Nigeria; which is in a bid to have a clear understanding of the direction of uncontrolled urban growth in the study area, with a view to proffering best solutions to its evaluation and monitoring. Data obtained through supervised classification were categorized into pre-processed images using different land cover classes. Change detection analysis was used to determine the urban growth areas between the study years (1989-2021) and make a projection for 2029. Findings revealed that the built-up area in 1989, 2002 and 2021 were 6.04%, 21.67 % and 36.42% of the study area, indicating a steady increase in the extent of the built-up area. The study estimated that the built-up area of Osogbo by the year 2029 will be about 75.28km2; an increase of 26.48km2 from the present area of 48.80km2. This study also revealed that the direction of growth in the projected year 2029 is towards the western periphery and the remote pockets located in the southern outskirts of Osogbo. These findings have implications for re-modelling urban sprawl. This study provides a basis for decision makers by enforcing planning standards, constant monitoring exercise, effective land administration and management and involvement of technology at all levels of planning.