Emergency services site selection: The integration of analytic hierarchy process and geographic information systems

Acil durum servislerinin yer seçimi: Analitik Hiyerarşi Yöntemi ve CBS entegrasyonu

Abstract

In the early 1980s Geographical Information Sys-tems (GIS) software emerged as a new information processing technology offering unique capabilities of automating, managing, and analysing a variety of spatial data. Many applications of GIS developed over the last decade provided information necessary for the decision-making in diverse areas including natural resource management, regional planning, and disaster management. Two perspectives on developing better decision sup-port capabilities of GIS can be identified, one based on analytical problem solving as a centrepiece of Spatial Decision Support Systems (SDSS) and an-other based on integration of GIS and specialized analytical models. According to first perspective, SDSS should offer modelling, optimization, and sim-ulation functions required to generate, evaluate, recommend, and test the sensitivity or problem solu-tion strategies. These capabilities are essential to solving semi-structured spatial decision-making problems. The second perspective on improving the decision support capabilities focuses on the expan-sion of GIS descriptive, prescriptive, and predictive capabilities by integrating GIS software with other statistical software and analytical models. Accord-ing to this view, mapping, query, and spatial model-ling functions of GIS can provide data display at different scales, preprocessing, and data input for environmental and statistical models. The general objective of Multi-criteria Decision Making (MCDM) is to assist the decision-maker (DM) in selecting the “best” alternative from the number of feasible choice-alternatives under the presence of multiple choice criteria and diverse cri-terion priorities. The problem of multicriterion choice in decision making is the paramount chal-lenge faced by individiuals, public and private cor-porations. The nature of challenge is two-fold: How to identify choice alternatives satisfying the objec-tives of parties involved in the decision-making pro-cess? How to order the set of feasible choice alter-natives to identify the most preferred alternative? The challenge of multicriterion choice can be at-tributed to many spatial decision-making problems involving search and location/allocation of re-sources. These problems, often analysed in (GIS), include location/site selection for: service facilities, retail outlets, critical areas for specific resource management, and emergency service locations where are key locations for effective emergency management. In this study, the criteria and its priorities/weights that should be considered for finding optimal loca-tions of fire stations are determined; and multi-criteria site analysis is conducted based on men-tioned criteria weights in (GIS) environment. More-over, in order to test the sensitivity and robustness of the model developed, a sensitivity analysis is per-formed based on the combination of the criterion weights by using (GIS) capabilities. With these anal-yses performed, it is focused on the creating the model that supports decision makers in decision-making for finding the optimal locations of fire sta-tions. In this study, these steps are followed: Definition of the problem/objective (determining the optimal locations of fire stations); determining the potential criteria in finding the optimal locations of fire stations; data collection and preparation and transfer to (GIS) environment; creation of raster data sets representing the regionalised criteria; classification of raster data sets; establishment of preference matrix, assigning preference values to the relevant criteria by using the pairwise compari-son feature of Analytic Hiyerarchy Process (AHP); determination of criteria weights by calculating ei-genvalues and eigenvectors of the preference matrix which evaluated by two decision maker group; de-termining the criteria priorities/weights values by using the synthesis of priorities and calculating the overall composite weights; calculating the result raster (suitability map for potential fire stations) as a weighted summation of all criteria raster data sets; conducting the sensitivity analyses in (GIS) en-vironment in order to test the sensitiveness and ro-bustness of the model developed; offering a system that supports decision makers in determining the optimal locations of fire stations. The integration of the (AHP) and (GIS) combines decision support methodology with powerful visuali-sation and analysing capabilities which should con-siderably facilitate finding optimal locations of fire stations and this process improves the decision mak-ing in emergency management.

Özet

Bu araştırmada itfaiye istasyonlarının yeni yerlerinin belirlenmesi aşamasında gözönüne alınabile-cek ölçütler saptanmış, Analitik Hiyerarşi Yöntemi (AHY) kavramından yararlanılarak herbir ölçüt için ağırlıklar belirlenmiş ve belirlenen ölçüt ağırlıklarına dayanarak Coğrafi Bilgi Sistemleri (CBS) ortamında en uygun yer analizi yapılmıştır. Ayrıca oluşturulan modelin duyarlılığını test et-mek amacıyla yine CBS ortamında duyarlılık analizleri gerçekleştirilmiştir. Gerçekleştirilen bu ça-lışmalar ile karar vericilere özellikle itfaiye istasyonları gibi acil durum servislerinin en uygun yer-lerinin belirlenmesinde verecekleri kararlarda destek sağlayacak bir sistem üzerine odaklanılmıştır. Çalışmada izlenen adımlar şu şekilde özetlenmektedir: Çözülecek problemin/amacın belirlenmesi; itfaiye istasyonlarının yeni yerlerinin belirlenmesinde etkili olası ölçütlerin belirlenmesi; verilerin elde edilmesi, hazırlanması ve düzenlenerek CBS ortamına aktarılması; parça parça olan veri gruplarının bir çalışma bölgesi oluşturacak şekilde düzenlenmesi ve herbir ölçüte (tabaka) karşılık gelen verilerin raster veri formatında betimlenmesi; raster veri gruplarının sınıflandırılması; Anali-tik Hiyerarşi Yöntemi (AHY) yardımıyla tercih matrislerinin oluşturulması; iki karar verici grubun görüşlerine dayanarak oluşturulan tercih matrisinden yararlanarak özdeğer ve özvektörlerin he-saplanması; AHY’nin sonuçların sentezlenmesi özelliğinden faydalanarak ilgili herbir ölçüt için önem/ağırlık değerlerinin belirlenmesi; ölçütlere ağırlıklı toplama işlemi uygulanarak sonuç raster verisinin CBS ortamında elde edilmesi; oluşturulan modelin duyarlılığının (CBS) ortamında test edilmesi ve yeni itfaiye istasyon yerlerinin belirlenmesinde karar vericilere destek sağlayan bir sis-temin önerilmesi.