Neighborhood dynamics of urban expansion based on morphological spatial pattern analysis and geospatial techniques: a case study of the Colombo metropolitan area, Sri Lanka

ABSTRACT This study examined neighborhood dynamics of urban expansion based on morphological spatial pattern analysis (MSPA) and geospatial techniques in the Colombo Metropolitan Area (CMA) of Sri Lanka from 1992 to 2014. Traditionally, urban expansion has been detected using absolute land use/cover (LULC) terms and landscape patterns (i.e. urban and non-urban). However, non-traditional characterization of urban expansion with neighborhood rules provides a better understanding of urban transformation which is essential to urban planners and managers. This study therefore used MSPA of Landsat images (1992, 2001 and 2014) to classify and detect the expansion of urban land uses based on neighborhood rules. Urban expansion intensity and topologies (infill, extension, and leapfrog) were also employed for further analysis. The results show that the CMA experienced rapid urban expansion, recording a 288% increase in the total urban footprint from 1992 to 2014. The annual urban expansion intensity was higher during the 2000s (1.45%) than during the 1990s (0.95%). Urban expansion topological analysis revealed that leapfrog was the most dominant pattern throughout the study’s temporal extent. An outward infill expansion from the city center was observed, while urban extension exhibited a ribbon-type development along the main transport corridors and coastal belts. The patterns and intensity of urban expansion in the CMA are directly linked to the economic, demographics, and political changes in Sri Lanka. Overall, the study provides an improved understanding of urban expansion in the CMA and offers directions that could be considered in future urban planning initiatives.