This paper studies the management of geographic information and knowledge flows for decision support in crisis situations. The authors compare and contrast a number of concepts that have been forwarded by academics as possible methodologies for the study of this area. The authors believe that they may have found an answer using system models combined with decision-making, information management and geographic information management models. Especially, the authors apply a system model about situation awareness. This model reflects to a state where a comprehensive mutual understanding and sharing of ideas between the decision-makers are provided. It supports the categorizing of geographic information and knowledge according to the user specific value and updating frequency. Currently a prototype of a decision support system based on the model is under development.