Coaches are using video analysis to evaluate the performance of a team in field hockey. Events with the ball are tagged and saved in a match annotation file, which is used to lookup video fragments. The match annotation enables a coach to lookup and to evaluate single moments of the match but doesn't provide a coach insight in the tactic. Tactic doesn't relate to single event but to a sequence of events. Currently it is not possible to evaluate the tactic. Because the match annotation contains information about the events, which includes the time and the location it is spatial-temporal dataset. To lookup a tactical pattern a coach it is required to express a tactical pattern on the spatial-temporal dataset. To enable a coach to incorporate his view of the game the flexibility is important. In this thesis work a system is designed which enables a coach to evaluate tactic by enabling him to express a tactical pattern and by visualizing the results. A prototype of the system is implemented to evaluate the design of the system. Coaches active at the top national and international level provided input for the system and participated in the evaluation of the prototype. The designed system provides a useful method to evaluate tactics by a coach. The system enables the expression of a tactical pattern by a coach in a flexible manner. This thesis presents the requirements for a system to analyze tactics. It also presents an approach to model and express a tactical pattern using a domain specific language. To create a tactical pattern a visual query interface is presented. The visual interface also offers the possibility to interpret the result of a query.