The observer sitting problem is important in terrain visibility analysis and is widely used in spatial information aid decision, telecom, and animal protection and so on.

观察点设置问题是地形可视性分析中的一类重要问题，在空间信息辅助决策、电信、野生动物保护等领域有着广泛的应用。

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The observer sitting problem is important in terrain visibility analysis and it is widely used in military, telecom, animal protection and so on.

观察点设置问题是地形可视性分析中的一类重要问题，在空间信息辅助决策、电信、野生动物保护等领域有着广泛的应用。

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But Miz Goodall believed that to understand animal behavior, the observer had to see the animals as individuals, not as interchangeable objects.

VOA: special.2009.11.18