Where are the jobs? Urban spatial structure and subcentering in an international comparison

全球北方最近的城市化进程的特点是集中和分散进程的双重性。知识密集型商业服务往往集中在城市地区，而离心力则在区域内占主导地位。这些相互竞争的力量体现在企业和员工的多中心城市空间结构中。关于这些进程的普遍性，可以说，它们发生在所有较大的和国际联系的大都市地区。此外，这些事态发展大大改变了这些地区的形态、职能和政治以及体制结构。然而，还应考虑到，重组进程已产生相当地方性和对背景敏感的结果。在这方面，特别是在北美和欧洲/德国大都市地区之间可以发现差异，显示出不同的就业区域分布模式和变化。然而，（副）中心发展的竞争力量的具体相互作用尚未得到充分理解。这同样适用于大都市地区的中心形成是否遵循相当收敛或相当发散的轨迹的问题。在这一领域进行的国际比较研究很少，现有的经验性工作-大多是定性工作-缺乏可重复的研究结果。此外，以前的研究是有限的，其空间粒度和其专题复杂性的形态模式及其随时间的变化的检测。因此，目前的研究建议解决了国际城市研究中的一个重大空白：在很大程度上缺乏对员工空间模式及其形态表现（例如建筑体积）的跨国比较研究，以及对这些模式随时间的形成和发展的解释。因此，本研究的目的是比较分析城市空间结构及其随时间的变化，在选定的美国和德国城市地区。此外，它的目的是通过市场驱动和规划诱导的力量的相互作用来解释城市中心的形成和发展。因此，主要的研究兴趣集中在形态相似的城市空间结构的意义上的收敛过程。从方法论的角度来看，本研究项目将联合收割机结合定量的横截面分析与定性的案例研究为基础的方法。利用这两个，最近的遥感数据（如德国TanDEM-X使命）和空间细粒度的官方统计就业提供了一套新的工具，将开发，允许分析大规模的形态模式，其三维表示在高空间精度。在选定区域进行的案例研究对调查结果进行了补充。

Recent urbanization processes in the Global North have been characterized by the simultaneity of both concentration and deconcentrating processes. Whereas knowledge intensive business services tend to agglomerate in urban areas, centrifugal forces dominate at intra-regional scales. These competing forces manifest themselves in a polycentric urban spatial structure of both firms and employees. With regards to these processes’ universality, it can be stated that they occur in all larger and internationally connected metropolitan areas. Moreover, these developments have substantially altered the morphological, functional and political as well as institutional structure within those areas. It should be also considered, however, that restructuring processes have caused fairly local and context-sensitive results. For that, divergence can be identified especially among North American and European/German metro areas revealing dissimilar patterns and changes of the respective regional distribution of jobs. Nevertheless, the specific interplay of competing forces of (sub-) center development has not been fully understood yet. The same applies to the issue whether center formation in metro areas follows rather convergent or rather divergent trajectories. Little internationally comparative research has been carried out in this field and the existing empirical work – mostly qualitative in nature – suffers from the lack of reproducible findings. Moreover, previous research is limited with respect to both its spatial granularity and its thematic sophistication regarding the detection of morphological patterns and their changes over time. The present research proposal therefore addresses a substantial gap in international urban research: a largely missing cross-nationally comparative investigation of spatial patterns of employees and their morphologic manifestation in e.g. built-up volume, as well as explanations of these patterns’ formation and development over time. Accordingly, this research proposal’s objective is to comparatively analyze urban spatial structure and its change over time in selected US-American and German city regions. It moreover aims to explain the formation and development of urban centers by the interplay of market-driven and planning-induced forces. Thus, the main research interest is focused on convergence processes in the sense of morphologically similar urban spatial structures. From a methodological point of view, this research project will combine quantitative cross-sectional analyses with qualitative case-study based approaches. Utilizing both, recent remote sensing data (such as the German TanDEM-X mission) and spatially fine-grained official statistics of employment provides a novel set of tools will be developed that permits to analyze large-scale morphological patterns regarding their three-dimensional representation at high spatial accuracies. The findings are complemented by case study research in selected regions.