复合目标的赋值──聚合操作

Value Assignment of Complex Objects-Aggregation Operations

介绍了有关目标聚合的一般特征，在ＧＩＳ软件Ｓｍａｌｌｗｏｒｌｄ上讨论了聚合操作的一般过程。按目标属性本身的特点，将数值聚合归为三个基本类，以实例形式介绍了这些属性值的聚合方法。并根据Ｓｍａｌｌｗｏｒｌｄ支持的面向对象语言ｍａｇｉｋ，利用面向对象的数据模型实现其聚合操作过程。

This paper introduces the common features of aggregations of objects. A general procedure of aggregation operations is outlined based on Smallworld. Depending on the characteristics of attributes,aggregations of attribute values can be boiled down to three basic groups.And an administrative area is taken for the experiment in aggregation operations.For the realization of data aggregations,magik-an object-oriented language supported by Smallworld is adopted to implement of those operations.