地质灾害危险性评价因子对格网大小的敏感性与误差分析

SENSITIVITY AND ERROR ANALYSIS OF CONTROLLING FACTORS DUE TO VARIATION OF GRID SIZES IN GEOHAZARD ASSESSMENT

格网单元是利用地理信息系统(GIS)进行地质灾害的危险性评价时广泛采用的一种评价单元。对研究区进行格网划分之后,需计算每一格网单元的评价指标值,并进行叠加分析,进而划分危险性等级。但是,格网大小的确定目前仍依赖于专家经验,缺乏定量的计算模型。本文以湖北省恩施市为例,选取了地质灾害危险性评价中常用的评价因子和指标,分析了格网大小对各评价指标的影响机理,为格网大小的定量计算提供了科学依据。

Image grid cell is a widely used mapping unit type in GIS-based geohazard assessment.Values of each controlling factor should be calculated and endowed to grids.Risk levels can be determined through overlay analysis.However,due to the lack of quantitative computational model,the determination of grid size is largely dependent on expert experience.Taking Enshi City as an example,this paper analyzes the influence mechanism of grid sizes on the most commonly used controlling factors.The results can provide scientific basis for the determination of grid size.