土地类型多级地理格网分类体系框架的建设构想

土地类型研究在综合自然地理学中具有重要的地位和意义。该研究虽在国内外已取得很多成果以及制图实践,但仍然有3个问题有待解决：（1）如何对土地类型进行系统分级、分几级;（2）如何选择土地类型各级指标要素;（3）如何利用多源数据进行计算机自动跨尺度土地类型制图。针对上述问题,本文基于国家标准地理格网提出一种土地类型指标数据库建设方案,即构建4级标准地理格网模型,以各级格网单元作为指标表达载体,选择土地类型研究普遍采用的地带、地貌、土壤和植被4要素,进行多级标准地理格网指标库建设框架设计。通过设计与分析,指出多级地理格网分类体系有其物质基础,即地球科学各学科都具有多尺度研究特征,各学科所具有的分类体系层次性可用多级格网来表达,尤其是影响土地类型分类分级系统的地貌、土壤、植被3个要素间存在相互作用,决定了三者分类体系分级数目和各级格网单元尺度应一致或相近。因此,本文基于标准格网体系,给出了一个土地类型指标数据库建设框架,以期用于土地类型研究与制图格网数据库平台的构建,为进一步开展土地类型制图实践研究提供新思路。

Concept of Building Multi-level Classification System Framework for Land Type Based on Grid

Land type (in the former Soviet Union, it is known as "landscape", and in Europe and the United States it is known as "land system") research has an important role in the integrated physical geography. Although the study on land type has made many achievements in the domestic and foreign research and there were a lot of land type mapping practices, there are still three key academic problems to be solved: (1) how to perform the basic land type classification and hierarchy and how many levels of hierarchy are needed, while the proof of land type classification system is lacked in previous mapping practices; (2) how to choose the land type indicators at all levels; (3) how to realize computerized cross scaling graphics technology using multi-source data. In this paper, a building method of land type indicator database has been designed, which could solve these problems based on the national standard geographic grid. A four-level standard grid system model is built, and the land type classification indicators are expressed respectively by the grid cells at different grid levels. We choose area, landform, soil and vegetation, which are often used in land type research, to be the indicators in designing the building framework of the multi-level standard geographic grid indicator database. Through the design and analysis process, we point out that the multi-level geographical grid classification system has its physical basis: all earth sciences have multi-scale research features and the hierarchical classification system for each subject could be expressed by multi-level standard geographic grid system model. Especially, the three elements of landform, soil and vegetation that are often used in land type classification system research are typical, due to the interactions among them. These lead to a conclusion that the number of classification levels for the three land types’ classification systems and the scale of grid cells at each level should be identical or similar. Therefore, the building framework presented in this paper is feasible and will help to address the three issues mentioned above. This framework should be used to guide the establishment of database and further land type research.