最近几年来，地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持，如城市管理、区划、环境整治等等，地理信息成为信息时代重要的组成部分之一； “数字地球”概念的提出，更进一步推动了作为其技术支撑的GIS的发展。 与此同时，一些学者致力于相关的理论研究，如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面，并且这两个方面构成了相互促进的发展过程。
5.21.1. I. sequence ¶
The binary search tree can be used as an implementation of the lookup table.
The purpose of using the binary search tree is to get the value right away by looking for key. Minimum, maximum, successor (successor), predecessor (precursor), floor (floor), ceil (ceiling, rank (which element is ranked), select (who is the element that ranks n) are all manifestations of the ordering of binary search trees.
5.21.2. II. Limitations ¶
The binary search tree is limited in time performance.
As shown in the following figure, like element nodes, two different binary search trees are formed, both of which satisfy the definition:
The binary search tree may degenerate into a linked list, accordingly, the search operation of the binary search tree is highly related to the tree, and the height of the tree is the number of nodes n of the tree, and the corresponding algorithms of the binary search tree are all reduced to O (n) level.