Analysis of the Impacts of Urbanisation on Land Cover Change in Gombe Local Government Area, Gombe State Nigeria

Abstract

Like many other Nigerian capital cities of newly created states in the 1990s, Gombe the capital city of Gombe State in the North-eastern geopolitical zone has experienced tremendous change in the land cover which is primarily driven by urbanisation. However, little is known on the extent of this urban expansion, how it has affected other land cover types or the dynamics of demographic change as a function of urban growth in the area. This spatial information is highly needed for effective planning and development. This paper, therefore, attempts to answer these questions by firstly, processing LandSat5 images of 1998 and Landsat 8 images of 2016 both of November of Gombe Local Government Area where the state capital is situated. Image processing is then carried out using the semi-automated classification plugin in QGIS 2.18. A supervised classification scheme was used to classify the 1998 and 2016 Landsat Image scenes into four land cover classes (water bodies, built-up area, bare-surface and vegetation) using the spectral angle mapping algorithm. Secondly, the paper analysed population data of Gombe Local Government Area for the same period to understand the dynamics of population change in the area. Based on the findings, urban land cover type increased from 13.02 Km2 (25.14% of the total land cover) in November 1998 to 25.98 km2 (50.17% of the entire land cover) in November 2016. As a result of this change in land cover, all other land cover types decreased in areal coverage. A Kappa index of 0.82 and 0.81 suggest that that the error margins during the supervised classification process of the 1998 and 2016 Landsat images are relatively small. The implications of rapid changes in land cover and population change in the area over a short period of 18 years on planning and management are also discussed.