关键词: 山地土地类型, 北京西山, 制图综合, 限区, 土地类型图, 垂直带, 山地景观, 清水河流域, 地形面, 外部形态特征

Abstract: The procedure of mapping the land types in mountainous region is quite differentfrom that in the plain. In the mountain ous region, it needs to begin with the studyingof the basic morphological features of the mountains. These include the vertical zona-tion, the atternation of positive and negative landforms, the aspects of slopes, and so on.Moreover, the formation of the morphological features of the land units should beanalysed also.In the practice of making the large and middle-scale maps of the land types in themountainous region, west of Beijing, two facts have been noticed. One fact is that the la-titudina position and the altitude of the mountain determine the spectrum of vertical zonesand its structure. The other is that the geological and geomorphological factors (geologi-cal structure, new tectonic movement, lithology, types of landforms, and so on) have im-portant relations to the differentiation of the land units and their structural characteris-tics. They also form the basis of different agricultural land. use. Therefore, these twofacts have to be studied carefully for giving a sound foundation for mapping.Several related problems should be studied further. They are:1. The hierarchy of the classification of the land units. We considered that thehierarchy should be "the vertical zones of mountain landscape, land system, facet andelements". Such a hierarchy not only agrees with the characteristics of the mountainousregion but is also useful to make comparison with the land types of the plain.2. Basic contents of maps of different scale, considering the characteristics of themountainous region and the present agricultural land use conditions, we suggest that:(1) for large-scale mapping, the land facet should be the main object; (2) for middle-scale mapping, the land system should be the main object; and (3) for small-scale map-ping, the vertical zone of natural landscape should be the main object. As for the landelement, it seems not feasible to be mapped.3. Legend design and nomenclature. Legend design and nomenclature should reflectthe comprehensive character of the land. Both the sequent legend and the two-row ormulti-row index legend can be used. Each has its advantages and shortcomings. Butin compiling the land type maps of the whole country, it is convenient to use the sequentlegend.4. The synthesis of the land type maps. We have attempted to synthesize the landtype maps according to the regional principle and the type principle. This involves theshape and boundary of the mapping units, the unification and adjustment of the legendsymbols, and so on. All these problems need to be studied further.