Abstract

The study assessed urban expansion that occurred in Offa within a period of twenty – four years (1990 – 2014). Three Multi temporal satellite imageries of LandSat TM 1990, LandSat ETM 1999 and LandSat ETM+ 2014; and administrative map of Offa were used as the primary dataset to process, classify (supervised classification), and analyze land use changes (urban expansion). Erdas Imagine 9.2 ArcMap 10.3 and ArcGIS 10.3 software were used for the analysis. Results obtained from the analysis of built-up area dynamics for the past three decades revealed that the town has been undergoing urban expansion processes. The expansion was prolonged both from urban centre to adjoining non-built-up areas in all directions. The total built up area in the town expanded from 17.57 km² (7.73%) in 1990 to 32.0 km² (14.07%) in 1999 and eventually to 65.09 km² (28.63%) in 2014, while agricultural land and natural vegetation had the highest net losses because of conversion to other uses, especially built-up.  The overall expansion between 1990 – 2014 was 47.52km². The study period 1999 – 2014 witnessed the highest urban expansion. Quantifying urban expansion patterns and development processes of the past trends can help better understand the dynamics of built-up area, guide sustainable urban development and planning of the future urban growth.

Key Words: Urban Expansion, Landuse/land cover, Satellite imageries, Remote Sensing, GIS