In this paper we argue that interfaces embedded in the world, one of the core objectives of ubiquitous computing, require interaction designers and researchers to have a stronger understanding of the environment as an aspect of the interaction process. We suggest that the interaction community needs new tools to accurately record and, as importantly, analyze interaction in space. We present one solution: People Watcher, a freely downloadable, iPad Application, specifically designed to address the `usability in space' issues. The paper reports a case study of the software's use. We go on to encourage researchers to adopt this tool as part of the wider process of understanding the effect of the spatial context in interaction design.