摘要
目前分类中所采用的聚类分析法多为系统聚类法。系统聚类法的基本思路是先将N个样品各自看成一类,然后确定样品或类与类之间的距离,距离最小的两类合并为一个新类;计算新类与其它类的距离,再将距离最近的两类合并。经过如此合并,直至达到要求的距离系数为止。由于距离系数的定义不同,其计算方法也不同。由系统聚类法的思路可知。
The method of modification by batches is a kind of dynamic assembled classification analysis, which defines a rough premary classification first, then modi-fied according to a diefinite principle till it becomes a rational classification. For determining the best vegetation cover fitting for growing on the Loess Plateau, and based, on the information obtained in experiments from 1983 to 1986 in Ansai County, the authors select nine varieties of vegetation cover for soil conservation. By making use of the above-mentioned method, the vegetation covers were classified according to their effectiveness for soil and water conservation. The result indicated that the vegetation covers of adsurgers and adsurgers intermittently in rotation with korshinkii is the best and can be taken as the major plant material for controllng soil loss in the loess plateau area.
出处
《中国水土保持》
北大核心
1991年第1期50-52,共3页
Soil and Water Conservation in China
