Detecting borders of urban activity spaces is essential for understanding urban dynamic structures. The emerging big geo-data help to extract valuable knowledge about the relationship between urban structures and human activities at fine granularities. Despite the well-developed urban structure and transportation network design technology, barriers attenuating intra-urban travel still exist as borders of urban activity spaces. To understand the effects of activity space borders, this study first delineates the activity space borders and identifies the borders into three categories: natural, infrastructural, and administrative borders. Then, the border effect from three types of borders is evaluated through the spatial interaction model revealing their influence on intra-urban travel connections. On basis of the modeling results, we introduce an indicator, border thickness, to measure the distance increased caused by each border of activity space. This study provides a border effect perspective for investigating the urban activity spaces. We reveal the different border effects for natural, infrastructural, and administrative borders. Further, we locate the thick borders and discuss their relations with the urban structure.

检测城市活动空间的边界对于理解城市动态结构至关重要。不断涌现的大地理数据有助于以精细的粒度提取有关城市结构与人类活动之间关系的有价值的知识。尽管城市结构和交通网络设计技术发展成熟，但削弱城市内部旅行的障碍仍然是城市活动空间的边界。为了了解活动空间边界的影响，本研究首先描述了活动空间边界，并将边界分为三类：自然边界，基础设施边界和行政边界。然后，通过空间相互作用模型评估了三种类型边界的边界效应，揭示了它们对城市内部旅行联系的影响。根据建模结果，我们引入了一个指标，边界厚度，以测量活动空间的每个边界导致的距离增加。这项研究为研究城市活动空间提供了边界效应的视角。我们揭示了自然，基础设施和行政边界的不同边界效应。此外，我们找到了较粗的边界，并讨论了它们与城市结构的关系。