This article studies the processes through wich a pupil interprets a cartographical document. In class, a pupil forms his representations of a world regarded as a stretch of land which has been socialy adapted. The interpretation of maps is not an innate or an automatic activity. The concepts of representation, of a cartographical expression System and of an iconic pattern allow us to have a better understanding and to give account of the cognitive processes and the semiotic relationship at work. A map articulates a graphical expression based upon induced analogy and a verbal expression based upon a sequential reading of symbols. The identification of cartographical forms depends upon a methodological learning and a certain knowledge of the nature of geography. This approach does not exhaust all questions related to geography, but has proved to be particulary adapted to these sets of spatial analysis problems.