Geo-information based assessment of the impact of urban sprawl in Akure, Southwestern Nigeria
This study analyzed land use/land cover change and examined the trends and factors responsible for urban sprawl in Akure between 1986 and 2011 with a view to developing a user-friendly geospatial database for monitoring urban sprawl in the study area. Medium resolution satellite images derived from Landsat (TM) and (ETM+) comprising of four dates (1986, 1991, 2002 and 2011) and high resolution Spot 10m satellite image of 2011 were acquired and used for this study. Akure Topographical Map of 1966 (1:40,000) was also acquired and used. Maximum Likelihood Supervised classification algorithm was used to classify the study area into four major classes, including built-up, high forest, agro-forest and water body. Subsequently geo-spatial database was modeled and spatial analysis was performed. Reconnaissance survey was carried out and GPS was used for groundtruthing. In-depth interview and structured questionnaire were carried out to examine the trends, factors and impact of urban sprawl in the study area. Descriptive and inferential analyses of correlation were used for further analysis of the data collected. The results of urban sprawl’s impact in Akure using the GIS-based study revealed that built up area increased rapidly by 43.31% from 5,857.54 hectares in 1986 to 8,394.21 hectares in 1991 and it also increased in 2002 by 4.39% from 8,394.21 hectares to 8,762.76 hectares. It further increased by 72.02% from 8,762.76 hectares to 15,073.7 hectares in 2011. The results revealed that built-up area, agro-forest and water body were the areas experiencing the most increase. Results of the correlation analysis indicated that the relationship between ’house ownership’ and demography explained most of the variation observed in the study. It was found that gender, marital status and number of children were more responsible for urban sprawl in Akure. The analysis showed that there was a weak negative relationship (r = -0.189, p < 0.01) between gender and ‘house ownership’, a weak positive relationship (r = 0.343, p < 0.01) between marital status and ‘house ownership’ and a weak negative relationship (r = -0.159, p < 0.05) between ‘number of children’ and ‘house ownership’ in the sprawl location. Subsequently, Geo-spatial database modeled was tested by subjecting it to some spatial search, query and overlay to show its capability to answer question pertaining to all the entities of the database. The study concluded that the rate at which urban sprawl increased in Akure due to marital status and other factors such as number of children and gender, if not reversed might constitute greater social and environmental problems that can impact negatively on sustainable development in the future.