EVALUATING SUITABILITY OF A GIS-AHP COMBINED METHOD FOR SUSTAINABLE URBAN AND ENVIRONMENTAL PLANNING IN BEYKOZ DISTRICT, ISTANBUL

摘要

Many metropolitan areas in the world currently face challenges of rapid urbanisation.At the urban peripheries,the balance between ‘urban areas‘ designated for new settlements for city inhabitants and ‘ green areas,” which provide ecosystem functions,has come under heavy pressure because of this rapid urbanisation.Spatial planning research provides methods for a thorough evaluation of urban develop- ment strategies.In this paper,a method is proposed that provides a systematic Suitability Assessment for the metropolitan territory,from the perspective of both urban planning basic principles and envi- ronmental sustainability.This approach,which combines Analytical Hierarchy Process (AHP) and Geographic Information System (GIS) techniques,is applied to a case study in Istanbul,Turkey,to evaluate current urbanisation patterns.Beykoz District spans an area of more than 30,000 ha at the Anatolian side of Istanbul,along the Bosphorus.Currently 79% of the total area is forested,15% is agricultural land and 6% is urbanised.These characteristics make it a unique and financially precious area.It is thus particularly important to ensure that urban planning and development in this district are sustainable.In the Suitability Assessment,six main parameters are included,namely slope,streambed,Natural conservation status priority,forested areas,agricultural areas and watershed areas.Twenty-four sub-parameters are weighted by the AHP technique and integrated levels of suitability are determined by weighted overlay using GIS.The final map produced using this combined technique shows how urban constructions are spreading on the urban fridge of the Beykoz District.The resulting suitability map provides for a better comprehension of alternative settlement locations for preserving nature and sustainable development.The systematic and fact-based characteristics of the described methodology add to the legitimacy of its outcomes.The proposed method can serve as a suitability assessment instru- ment to analyse future urbanisation plans on their wider implications in terms of sustainability.