People use maps for directions and sightseeing, but they rarely consider the process of map-making. Since maps are made by several creators cooperatively, map-making can be considered a collaborative decision-making process. If this process is analyzed, we may discover that environmental factors influence map-making. This study discovers the effects of environmental factors for map-making through experiments and analysis. We invited participants to join in the experiments, in which they made a tourist map for a familiar place, and we controlled the environmental factors in the map-making process. The environmental factors include the following: (1) the number of creators, (2) the presence of creators’ conversations, and (3) the creators’ space. We analyzed the created maps, tourist attractions, and participants’ conversations to determine the effects of the environmental factors and found the following three effects: (a) If the creators are many, then more tourist attractions will be mapped, which corresponds to factor (1). (b) If the creators have conversations, the rate of minor tourist attractions increase, which corresponds to factor (2). (c) If the map-making environment is virtual, then the map has more tourist attractions than a physical one, which corresponds to factor (3). We discovered the above effects of the environmental factors in tourist map-making. According to the results of this study, it is expected that people can obtain their desired maps using these factors and effects