This paper argues that urban systems issues are design problems on a grand scale and that various disciplines aiming to address them can have only a partial view of the problem. It is necessary to draw boundaries around the detailed analyses of specific issues, but a way to map the wider system, to contextualize and more deeply understand how they are interrelated, is still lacking. Four complexity obstacles related to reasoning about complex systems are in our way, and to our knowledge no existing approach navigates them effectively. We propose a tool called the Abstraction Hierarchy as a way to do just this, in order to frame complex issues on a large scale, in a way accessible to all disciplines. To demonstrate the power of this systems model, the Abstraction Hierarchy is applied to an urban area. Through its application we demonstrate its capability to navigate all four obstacles and investigate previously unexplored space in urban systems research.

中文翻译：

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城市系统：映射相互依存和结果以支持系统思考

本文认为，城市系统问题是大规模的设计问题，旨在解决这些问题的各个学科只能对此问题有部分看法。有必要围绕具体问题的详细分析划清界限，但是仍然缺少一种方法来绘制更广泛的系统，进行情境化和更深入地了解它们之间的相互关系。与推理复杂系统有关的四个复杂性障碍正在我们的面前，据我们所知，没有现有的方法可以有效地解决它们。我们提出了一种称为“抽象层次结构”的工具，以此作为实现此目的的一种方法，以便以一种适用于所有学科的方式大规模地构建复杂的问题。为了演示此系统模型的功能，将抽象层次结构应用于市区。