Quantitative Assessment of Remotely Sensed Data for Landcover Change and Environmental Management

This paper examines the relevance and application of quantitative techniques in geographic study with emphasis on landcover change and environmental management in a typical urban city of Warri and its environs in Nigeria. It uses an experimental study that adopts Principal Component Analysis (PCA) and Accuracy Assessment in reducing data dimensions and enhancing image visualization for onward classification into landcover classes using 1987 TM, 2002 ETM+ and ETM+ 2011. The 2011 ETM+ was later excluded due to scan line and cloud cover errors. The PCA results show that 1987 Bands of 145 has variance of 834.71 (88.09% of total components) while the 2002 Bands of 147 has variance of 1287.21 (85.344% of total components). Supervised classification results show overall accuracy of 96.19% (for 1987) and 96.30% (for 2002) respectively. The study reveals that there was increase in urban landcover (17.2% to 34.93%) and swamp (10.11% to 11.61%). Correspondingly, light vegetation and thick vegetation decreased from 41.76% to 27.38% and 26.31% to 22.36% while water also reduced from 4.63% to 3.73%. The study indicates a higher demand for urban settlement which requires landuse control to avoid urban blight and environmental decay.