The importance of including a children’s perspective as a basis for urban planning is made clear by studies pointing to discrepancies compared to adults’ views and to an unwillingness/inability among decision-makers to take children’s interests into account. There is much support from practice and research that children, even young ones, have knowledge of their neighbourhoods relevant to physical planning, and also that many children want to communicate their experiences and ideas to planners and managers. Children’s participation in planning is advocated in the UN Convention on Children’s Rights and in Agenda 21 documents. There is a need for child-friendly methods to facilitate the participation of the young ones as well as a need for planner-friendly results in projects involving children. Practical experiences of the work in Norway with the “Children’s tracks” method and of some studies in Sweden and Finland point to the need of using real maps in communication with planners. The aim of our study is to develop a method, which facilitates the process of bringing children’s information of their local environment into the official planning process, working with children and their teachers at school. We are investigating how children can store and present knowledge about their local environments into a computerized geographic information system (GIS), the same system that constitutes the basis for spatial planning in Swedish municipalities. We are looking into the demands by planners for basic planning information concerning accessibility and reliability with the intention of finding a way for the children and their teachers to put the information into a GIS-system without help of GIS-experts. Following up the experiences from “Children’s tracks” our method will include also the teachers mapping of the school’s use of the local environment. We are developing our method in close contact with active planners and connecting to a tool for analysis of free spaces – the Sociotopical method - constructed within the Stockholm City Administration. At this stage we can present and discuss early results from two schools in outer districts of Stockholm (Sätra, Bredäng) and one from the inner city (Kungsholmen) where in all 70 pupils in the fifth/sixth grade and six teachers have tested GIS-mapping. We want to demonstrate and discuss the design of our GIS-application as well as our techniques for testing the reliability of results. How can we get the method to work in both ends – for the children/teachers as well as for the planners? This study is part of the interdisciplinary research project “Children and Open Spaces in the City. Accessibility, Use and Influence” that runs from July 2002 until December 2004.