基于对象及隶属规则的海岸水边线提取方法

Algorithm for Extracting Transient Coastal Water Edge Line Based on Object and Membership Rule

以在分辨率、光谱成像能力等方面具有优势的Sentinel 2A为数据源,突破传统以像元为研究单元提取海岸水边线的思路,构建以像元聚类形成的语义单元为对象,获取决策分类规则后,基于隶属度及模糊函数获取海岸水边线位置的方法。结果表明,本文方法解决了传统分类方法在下垫面地物类型复杂条件下不易于采用传统分类方法提取海岸水边线的限制条件。基于面积法的距离准则线段匹配法和断面线距离分析方法应用于海岸水边线精度评价的结果显示,本文方法提取的海岸水边线位置与传统目视解译方法得到的海岸水边线位置在约85%的区域具有一致性,误差的集中区域表现在近岸和近海地物波谱相似处,如受水质水深、悬浮泥沙等影响的淤泥质潮滩处以及受人工海岸开发影响的近岸地区等,建议在这些地区结合目视解译的方法进行海岸水边线的位置修正,进而快速、准确地获取海岸线的真实位置信息,为海岸带生态环境保护、海岸带开发的合理规划和建设,以及经济与环境的科学协同发展提供技术支持。

By taking Sentinel-2A images which have advantages of spatial resolution and spectral imaging capability as the data sources and taking semantic unit formed by pixel clustering,rather than the traditional pixel-based unit,as the object,a method for acquiring the positions of coastal water edge line is proposed based on membership degree and fuzzy function and after the decision rules required.This method can solve the problems that the traditional classification methods cannot be easily used for extracting the coastal water edge line under the case of complex coastal conditions.For evaluating the accuracy of the extracted coastal water edge lines,the distance criterion line segment matching method and the section line distance analysis method based on the area method are applied.The results indicate that the positions of the coastal water edge lines extracted by the proposed method are consistent with those obtained by traditional visual interpretation method in about 85%of the study area.The error-concentrated areas are mostly at the places where the spectra of inshore and offshore ground objects are similar,such as the muddy tidal flat regions affected by water quality,water depth and suspended sediments,the coastal regions affected by artificial coastal exploitation,and so on.It is,therefore,suggested that at these places the positions of the coastal water edge line should be corrected by combining the visual interpretation method,in order to acquire the real position information of the coastline fast and accurately.This proposed method can provide technical supports for the protection of coastal ecological environment,the rational planning and construction of the coastal development and the scientific synergetic development of economy and environment in the coastal zone.