We present the SketchMap system, which integrates outdoor and classroom activities to support children's collaborative learning. Individual children create maps near their school in an outdoor environment using a SketchMap client. The maps are uploaded to the SketchMap web server for sharing among the children, who have created maps of different areas. Children can edit or add new information to the maps in their classroom or in their home. The goal of the SketchMap project is to investigate whether integrating outdoor and classroom activities, and sharing children's experiences through the maps can actually promote their collaborative learning and nurture learning communities including teachers and parents. The SketchMap system has been used in "Safety Map" and "Nature Exploration" classes in a Japanese elementary school. Evaluation of the SketchMap system is in progress, and issues found through the educational practices are described.