The algebraic language Time-AgLOTOS was recently proposed to describe the time-dependent behavior of an ambient intelligent agent. The Spatio-Temporal Planning System (STPS) is a contextual model capturing all possible evolutions of an agent plan including context changes. It provides formal description of the possible actions of a plan supporting timing constraints, action duration and spatial requirements. Thereby, it can be derived from Time-AgLOTOS behavior expressions. In this paper, we propose a finite and symbolic representation of the STPS based on a number of spatio-temporal regions, preserving both time progress and location modeling. The resulting structure offers new possibilities and strategies for taking agent real-time decisions in context-awareness manner.