| World Cultural Heritage sites are an irreplaceable record of human culture,history and civilization that are priceless with an Outstanding Universal Value(OUV).World cultural heritage not only links a society to its history and help to create a cultural identity unique to their geography and customs,but also provide unique insights into how different societies interacted in the past,and therefore these sites provide a cultural resource that needs preservation and continued protection to ensure that it can passed down to future generation.Unfortunately,world cultural heritages are facing increasing risks,in particular climate change,frequent disasters,intensified human activities and environmental deterioration has brought about an unprecedented negative impact on the world cultural heritage.These heritage sites are facing risks that are complex and interconnected and therefore risk identification,analysis and assessment tasks require a long-term complex and multidisciplinary effort.Cultural heritages have distinctive temporal and spatial features in terms of spatial scale,geometric structure and materials.Remote sensing technology,due to its non-intrusive,objective,mutli-scale and frequent data collection capabilities,and Geographic Information System(GIS),providing powerful management and analysis capabilities for spatial data,collectively provide effective tools for risk identification,monitoring and assessment of cultural heritage.Based on the risk characteristics of cultural heritage,this work proposes establishment of a risk management process based on remote sensing and GIS,to identify,analyze,and evaluate risks,towards effective response,and presents a prototype comprehensive risk research system,oriented towards 'authenticity' and 'integrity' of “Outstanding Universal Value” of World Heritage.Taking Angkor World Heritage site as a research area and object,this study analyzed the impacts of natural disasters,human activities and ecological environment on it.Based on remote sensing data,the study developed a risk evaluation model to calibrate the parameters of evaluation model of hazard risk level,carry out model operation,verify evaluation and output results,and finally put forward countermeasures and suggestions on sustainable development of Angkor world heritage site.The main research results and innovations are as follows:First,this study proposes a risk research framework based on remote sensing and GIS,oriented towards the “Outstanding Universal Value” of World Heritage.By analyzing the 2,218 risk reports on 407 world heritages between 1979 and 2018,this paper expounds on the current risk management and protection status of heritages in different regions or countries,and proposes risk factors that may have great influence on cultural heritage sites.Through risk identification and monitoring of heritage sites by means of remote sensing technologies,this paper conducts risk analyses on the basis of geographical information system technologies,establishes a risk evaluation model for cultural heritage sites,realizes the identification of risk types of natural,human activities and environmental risks,and quantitatively analyzes scope of risks,as well as heritage sites' degree of response to changes,thereby establishing an integrated risk research framework.Second,this study carried out flood risk assessment for Angkor world heritage site.Utilizing long-time series SAR data,the identified and selected inundated areas between 2007 and 2013 and evaluated for indicators of flood risks at Angkor,namely inundation frequency,absolute elevation,elevation standard deviation,and drainage density,and worked out the weighted value of the four indicators by constructing a judgment matrix.Utilizing multi-parameter method and GIS spatial analysis and decision-making functions,the study developed a Flood Hazard Index(FHI)model innovatively to provide a flood risk map for flood risk assessment.Third,this study,utilizing remote sensing data on land utilization(2004-2017),modeled the process of the urban expansion,to evaluate the temporal and spatial variations in land use,evaluated the scope of built-up area in Siem Reap city and analyzed the types of lands being converted for urban purposes in Siem Reap city.The paper also evaluated the level of influence of urban expansion on Angkor monuments,core zone and buffer zone.Based on the CA-Markov model,this study simulated the urban expansion of Siem Reap in 2020,2025 and 2030,to forecast the number of monuments likely to be affected by urban expansion in the next couple of decades.Based on this forecast,the study also evaluated the protection zoning policy of Angkor heritage site,and found contradictions between heritage site protection and urban development.The evaluation results suggest that the policies on conservation of Angkor heritage site have not yet been strictly implemented.Therefore,effective measures are needed to be taken to control the urban sprawl of Siem Reap city.Fourth,the study evaluated the environmental sensitivity of Angkor heritage site by identifying key ecological resources of Angkor heritage site that are located in Siem Reap province and charting single factors of vegetation,slope,land utilization,and flood risk.Through the superposition analysis of maximum value method in GIS environment,the study conducted an ecological sensitivity analyses on heritage sites,core zones,buffer zones and protected areas in Angkor heritage site.Results show that most of the central area of Siem Reap province is in low to medium sensitivity,accounting for 31.7% of the total area.The ecological sensitivity of Siem Reap province and the surrounding sites are not optimistic and the non-sensitive areas exhibit a tend to expand further.The main contribution of the research include: innovative Flood Hazard Index(FHI)model of Angkor,in response to the long-term flood hazards of Angkor World Heritage,and the development of the flood risk zoning map of Angkor;quantitative analysis on the patterns and processes of urban expansion around Angkor,the temporal and spatial changes of land use,the source and sink analysis of urban expansion land types,and the extent to which the heritage sites are affected at different scales and extents;the scope and impact of future urban expansion on Angkor based on the CA-Markov model;ecological sensitivity zoning of Angkor's environment,providing a reference for Angkor's sustainable development;a proposed system and framework for integrated risk research based on remote sensing and GIS.The main conclusion that can be drawn from this study is that the contradiction between heritage site protection and economic development is still prominent,and the risk prevention policy of heritage site needs to be further strengthened.The findings of this study can provide a scientific reference for the integrated research on risk identification,analysis,assessment and response of cultural heritage sites using spatial information technology.This study also tries to do some useful research in promoting interdisciplinary research,and innovative development by integrating the spatial information technology,world cultural heritage protection,and integrated risk management. |
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