Situation Awareness is the capability of understanding what is happening in order to make informed and correct decisions. The process for gaining good levels of Situation Awareness is defined as situation assessment. One of the main tasks of situation assessment is the identification of the situation. Expert-based and learning-based techniques can be used to automatically identify a situation by processing the available information. In this paper, we propose an approach for supporting situation assessment using Dominance-based Rough Set analysis to learn decision rules from a set of example decisions made by experts, hybridizing both expert-based and learning-based techniques. A case study for Maritime Situation Awareness demonstrates the capability of the approach to support the situation assessment.