大比例尺土壤保持服务制图分级方法研究

科学地编制生态系统服务空间分布图，有助于识别生态系统优先保护热点及空缺，能够为国土安全规划提供基础信息。但由于缺乏统一科学的生态系统服务分级方法，生态系统服务分布图的展示效果和制图效率都受到限制。不恰当的分级制图会误导决策者对生态系统服务空间分布特征的判断，增加生态保护决策的不确定性。以构建生态服务制图分级标准为目标，对我国6个典型县区的土壤保持服务数据展开1：25万比例尺制图分级案例研究。采用分级精度、面积均衡性、极差一致性、空间自相关一致性4个分级质量评价指标评价并比较了目前地图编制中常用的自然断点法、几何间隔法、累积比例法、等差法、分位数法5种分级算法的分级制图效果。结果表明，6个县区有相似的土壤保持服务分布特征：低值区覆盖面积大，高值区覆盖面积小。各县区土壤保持服务制图最优分级方法有差异：延庆区、丰满区最优分级方法为自然断点法；永靖县、天山区、安宁市最优分级方法为累积比例法；富阳区最优分级方法为几何间隔法。各分级方法中，累积比例法在6个县区综合制图效果最优或接近最优，适用性最好，能够较好的刻画各县区的土壤保持服务空间分布特征。本文提出的分级评价方法及其结果，可为生态系统土壤保持服务制图规范化和自动化提供科学依据。

Research on the classification methods of ecosystem service of soil retention for large-scale choropleth mapping

Scientifically compiling the spatial distribution map of ecosystem services is helpful to identify hot spots and vacancies of ecosystem services, and can provide basic information for homeland security planning. However, due to the lack of a unified and scientific classification method of ecosystem service capacity, the display effect and mapping efficiency of ecosystem service distribution maps are limited. Inappropriately hierarchical mapping will mislead decision-makers to judge spatial patterns of ecosystem services and increase the uncertainty of ecological protection decisions. Aiming at constructing classification standards of ecological service mapping, a 1:250000 scale mapping classification case study was conducted on the soil retention data of six typical counties in China. Four classification quality evaluation indicators, including the Accuracy of Classification, the Areal Equality, the Equality of Value Ranges of Classes and the Spatial Autocorrelation Consistency, are used to evaluate and compare five classification methods commonly used in maps of ecosystem services, which are the Natural Breaks, the Equal Interval, the Geometric Interval, the Cumulative Ratio and Quantile. The results show that the six counties have similar distribution of soil retention services: the low-value area has a large coverage area, but the high-value area has a small coverage area. There are differences in the optimal grading methods for soil retention service mapping among counties: the optimal grading method for Yanqing and Fengman is the Natural Breaks; the optimal grading method for Yongjing, Tianshan, and Anning is the Cumulative Ratio; for Fuyang, the Geometric Interval is the optimal. Among the various grading methods, the Cumulative Ratio has the best or near-optimal comprehensive mapping effect in 6 counties, and has the best applicability for describing the spatial patterns of soil retention service in each county properly. The classification criteria and results proposed in this paper can provide a scientific basis for standardization and automation of ecosystem soil retention service mapping.