Evaluating On Regional Land Ecological Security Based On OWA-GIS

Due to the powerful spatial data management and spatial analysis capability, Geographic Information System (GIS) has become an important technological method for assessing land ecological security. However, the current land ecological security assessment method based on GIS had some deficiencies, which was lack of consideration of varieties of decision-making. The assessment method specifically could not reflect the relative importance under different criteria, the preference and attitude of decision makers, and sort the results of plot to-be-evaluated. The assessment method lacked flexibility; therefore it was not conducive to analyze various decision strategies comprehensively. In this paper, the proposed OWA (ordered weighted averaged) model integrated with GIS would be used in the multi-criteria land ecological security assessment. It made up for the complex spatial multi-criteria decision-making deficiencies when using the traditional GIS-based land ecological security assessment, made the evaluation results more diverse, flexible and practical, and reflected the different preferences of decision makers.OWA is a decision-making method, which can arbitrarily choose the importance among different indices according to the decision-risk coefficients. OWA multi-criteria aggregation can produce a wide range of decision-making strategies after adjusting the order-weight and criterion-weight, and then changing the decision-making risk coefficient. In this paper, OWA multi-criteria decision making methods integrated with GIS are adopted for the land ecological security assessment, the main contents summarized as follows: (1) analyzing the land use situation and the problems of land ecological environment in the study area; (2) selecting 19 indices (criteria) which affect the land ecological security from the three levels of land ecological security, land economic and social security, and land ecological security; then establishing the Miyun evaluation index system of land ecological security ; (3) processing data normalization, rating assignment and vector under the support of ArcGIS 9.2 on the basis of remote sensing image, statistical data and other literature of Miyun, Beijin; (4) converting the ArcGIS 9.2 19 evaluation indices vector data into the IDRISI 2.0 grid data, calculating the criterion-weights of each index using the analytic hierarchy (AHP), choosing fuzzy quantified methods to calculate the order–weights of each index, integrating the grid layer of 19 indices, corresponding criterion-weights and order-weights by the OWA function of the multi-criteria evaluation module (MCE) in IDRISI 2.0, evaluating the land ecological security of Miyun, Beijin, analyzing the results of the evaluation under different risk decisions, and comparing the new method with the traditional GIS overlay analysis method; (5) serving the result of the land ecological security assessment under different risk decisions as a factor of the tourism location selection, choosing transportation, tourist attractions, geological disasters as the tourism location selection factors and the banning construction area in"limit built area planning in Beijing (2006-2020)"as limiting factor, and then studying the land used for tourism location selecting decisions from the perspective of land ecological security by OWA - GIS method to calculate the criterion-weights, order-weights of affecting factors.The results indicated that: (1) The land ecological security assessment method based on OWA-GIS took into account the different risk decision strategies (decision risk factors was 0.0001, 0.1, 0.5, 1, 2, 10, 1000) and put forward seven decision strategies after calculating each evaluation criterion-weights and the order-weights. Comparing with traditional GIS overlay analysis, the OWA-GIS method could reflect the decision maker's preference better, and also helped the decision maker choose one of 7 strategies from"only an index meets the requirements"to"all of the indices meet the requirements". Therefore, it was conducive to analyze a variety of decision strategies comprehensively, solve the complex problem of spatial multi-criteria decision support conveniently, and make the evaluation results more diverse and flexible. From the seven decision strategies, the land ecological security of Shicheng town, Chiwengzhuang town, Mojiayu town were in good condition. (2)The OWA-GIS tourism location selection method was proposed from the perspective of the land ecological security, which reflected the considerations of various factors, and the focus of each strategy varied correspondingly. In this paper, the best areas for tourism development mainly concentrated in the northern and southern regions of Fengjiayu town, and Chiwengzhuang town and Mojiayu town in the south of the Miyun Reservoir.