Motivation - A situation map that shows the overview of a disaster situation serves as a valuable tool for disaster response teams. It helps them orientate their location and make disaster response decisions. It is, however, a quite complicated task to rapidly generate a comprehensive situation map of a disaster area. In this paper, we report on an investigation of how two persons can collaborate to make a situation map. Research approach - We performed a controlled laboratory experiment, in which 32 participants (grouped into 16 pairs) made a situation map of incidents. The experiment was set up as a two-way repeated-measures design with the type of collaboration and the availability of confidence level information as within-subject factors. Findings/Design - The results suggest that the collaboration type can affect the quality of the situation map. Additionally, the results also suggest that the availability of confidence information influences the discussion process during collaboration. The participants perceived the availability of confidence level information as being positive. Research limitations/Implications - The order of using the types of collaboration might have caused a learning effect by participants. Furthermore, the lack of a practice session might have had an influence on participants' object recognition during the first session of the experiment. Originality/Value - The study takes the position that the affected population in a disaster can actively participate in the situation-map making process. Take away message - Situation map-making might benefit from a simple collaborative action such as sharing a map including confidence information.