A Multi-Criteria Spatial Modelling Framework for Port-Urban Growth in a Coastal City System: The Vizhinjam-Trivandrum Corridor, India

Coastal port-city regions operate as intricate urban systems, where transport infrastructure, land-use change, environmental limits, and socio-economic forces interact across multiple spatial and temporal scales. In rapidly evolving coastal cities, port-led development may bring economic opportunities, but it also tends to introduce new environmental risks and social tensions. This duality is especially visible in cities where growth is unfolding faster than planning frameworks can adapt, which suggests a need for analytical approaches that are both integrated and spatially grounded. This study develops a multi-criteria spatial framework to assess land suitability and identify potential growth nodes along the Vizhinjam-Trivandrum corridor in southern India shaped by the development of the Vizhinjam International Seaport.The framework integrates multi-temporal remote sensing data, geospatial indicators, and expert-derived weights using the Analytic Hierarchy Process (AHP) within a GIS environment. Land-use and land-cover dynamics from 2005 to 2025 are analysed alongside transport connectivity, environmental sensitivity, geo-hazard exposure, economic feasibility, and socio-regulatory constraints. These factors are represented as interconnected components of the urban system. To balance analytical rigour with practical applicability, literature-based indicators are consolidated into a concise hierarchical structure. This structure encompasses physical environmental, infrastructural, economic, and socio-community dimensions. Expert judgement is incorporated through structured pairwise comparisons, producing a transparent and reproducible weighting scheme.The resulting analysis produces a spatial suitability surface that highlights development potential and constraints across the corridor. Early findings indicate that proximity to port infrastructure and transport connectivity strongly influence emerging growth patterns. At the same time, this advantage is often offset by environmental sensitivity and hazard exposure. These overlaps point to some of the core trade-offs that define port-city development, particularly in ecologically fragile coastal settings. By combining urban change monitoring with spatial decision-support analysis, the proposed framework demonstrates the value of integrated approaches for supporting sustainable and resilient development in complex coastal urban environments.