Spatial multi-criteria decision analysis for sustainable urban expansion: a case study of Trincomalee, Sri Lanka

Abstract

Rapid urbanization shapes the global environment. United Nation projections show that 68% of the population will live in cities by 2050, causing land demand, infrastructure stress, and environmental risks. In Trincomalee, accelerated growth, infrastructure deficits, and pressure on forests, wetlands, and coastal areas create planning gaps. This study applies an AHPbased multi-criteria suitability approach to support Trincomalee’s development plan by generating fine-grained, empirically derived suitability maps, overcoming limitations in current macro-level zoning and setting the foundation for a more systematic evaluation of future expansion needs. Although several studies in Sri Lanka have explored urban growth, a clear gap remains in district-level, high-resolution suitability assessments that integrate both environmental sensitivity and development priorities. To respond to this gap, this study develops an AHP-based GIS model aimed at identifying the most appropriate locations for sustainable urban expansion in Trincomalee. The outcomes offer practical value for planners by providing transparent, evidence-based spatial guidance that supports responsible land allocation, reduces conflicts with sensitive landscapes, and strengthens long-term, climate-resilient development planning.