Design of a GIS and multi-criteria based land evaluation procedure for sustainable land-use planning at the regional level

of comprehensive, standardized land evaluation tools is challenged by constraints of scale, data availability, validity, and mathematical translation and combination of diagnostic indicators. This study aims to design a GIS-based multi-criteria land suitability analysis that integrates agro-ecological aptitude, environmental impact and socio-economic feasibility criteria in a step-wise procedure combining recent advances in indicator selection, evaluation and weighing - exploiting information from various data sources - with functional mathematical combination procedures. The procedure involves: (1) selection of diagnostic land characteristics, (2) design of the corresponding evaluation criteria and consequent scoring of the diagnostic characteristics, (3) arithmetic combination of the scored characteristics into partial performance indices for agro-ecological aptitude, environmental impact and socio-economic feasibility, and (4) classification of the performance indices into aptitude, impact, and feasibility classes and determination of the overall land suitability class of the proposed land use. The tool's performance and applicability proved successful in a case study, identifying expansion zones for rubber in Quang Tri province, Vietnam. Local expert knowledge, relevant literature sources, factor-yield relationships and the discriminating power of different land characteristics within the given environment were successfully integrated to select, score and weigh diagnostic land characteristics. Explicit distinction between factors and constraints depending on the fuzziness of their spatial patterns, and between limiting and non-limiting factors depending on their impact and interaction, furthermore allowed to apply the most relevant arithmetic combination procedures.