Urban Extension in Calabar: A Remotely Sensed Assessment

Abstract

Urban places in the developing world like their advanced counterparts are experiencing unprecedented extensions, although mostly in an uncontrolled manner. Calabar is no exception to such urban extension, with notable sprawl especially with increased densification within the city and expansion along the fringes. This study aimed at assessing landuse/ land-cover (LULC) changes in Calabar between the year 2000 and 2018. 30 m Landsat imageries of both years were acquired from the Landlook platform. The imageries were subjected to the unsupervised classification process using the Iso Cluster and Maximum Likelihood Classification tools. Measurements were done on the raster outputs to allow for a comparison of the LULC statistics which assisted in identifying the rate of urban extension in Calabar over the period. Results showed that in the year 2000, out of the total 164.3 square kilometers (sqkm) covered by the city, the extent of urban built-up was 28.7 sqkm and 62.2 sqkm for green areas. However, in the year 2018, the urban built-up area increased to 44.8 sqm and green areas witnessed a reduction to 52.7 sqkm.  Wet lands also reduced in the area by 5.2 sqkm. Likewise, built up areas had a percentage change rate of 56.10 while green areas and wet lands had -15.27 and -9.3 percent change rates respectively. The spate of urban extension and encroachment into green areas and wet lands in Calabar is obvious and inevitable. It is thus necessary that measures be taken by relevant government agencies to monitor and manage the urban extension, such that the development is organized and sustainable.