This formula syntax is a little tricky: inside the I calls, the arithmetic symbols have their usual meanings, so the first I , for example, means: 2 times PI times x, divided by 365.

这个公式语法有些复杂：在I调用内部，算术符号与它们通常的含义相同，所以，例如第一个I表示：2乘pi乘x，再除以365。

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This paper analyzes the rule of composition of a map of 3d statistic map symbols. They are divided into three kinds: simple symbols, compound symbols and combination symbols.

分析了三维统计地图符号的构图规律，并将其分为简单符号、复合符号和组合符号3类。

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And according to forms, they can be divided into internal and external, which consists of characters, symbols, graphs and operations and each of them, is exemplified.

从形式上划分：包括内在表征和外部表征，其中外部表征又分为文字、符号、图形（表）和操作四种方式，并分别结合实例作出说明。

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