Integrated Geographic Information Systems―Based Suitability Evaluation of Urban Land Expansion: A Combination of Analytic Hierarchy Process and Grey Relational Analysis

Suitability evaluation for land is a complex task due to tensions between the need to develop residential and industrial areas and the wish to preserve high biodiversity and heterogeneous landscapes. We proposed an integrated method for land suitability evaluation (LSE) based on geographic information systems (GIS) under uncertainty. The method of grey relational analysis (GRA) was incorporated into analytic hierarchy process (AHP) to address the uncertainty during the process of evaluation. The systematic evaluation approach was tested by using urban expansion land in Changsha City as a case study. Based on the land-environmental information system database, the evaluation indicator system was established, which consisted of three subsystems criteria (biological and water resources, soil resource, and society and economy) and eight factors. Results show that the sum of highly suitable, moderately suitable, and marginally suitable land covers an area of 6,561.27 km super(2), 55.48% of the total land area in Changsha City. However, 44.52% of the total area (approximately 5,265.45 km super(2)) is currently not suitable land or permanently not suitable land, which illustrates that most areas in Changsha City are suitable for urban development. These outcomes can be used as a basis for policy makers, urban and regional planners, and researchers to deal with the development of cities and their surroundings in regions of highly ecological and environmental sensitivity.