This paper studies the spatial metaphors that underlie recent graphical interface design, looking at bidimensional and three-dimensional representation of objects, as well as at the semantic space where they place the user, and the kinds of actions that they allow her to perform. Since the first well-known folders and desktop metaphors for a graphical user interface, and the concept of layered and resizable windows; operating systems and applications have experimented with more or less abstract representations of space to place the user in a well known context where she can apply her "Real Life" skills to efficiently relate to the computer. Spatial metaphors range from those that try to reproduce the physical object or experience as faithfully as possible to those that create highly stylized spatial representations, based less on reality than in the need to make relationships and hierarchies evident. The paper analyses the advantages and disadvantages of these approaches, examining recent graphical interface design to find out what metaphors are efficient for which tasks and the cultural backgrounds they are based on in order to be successful rhetorical vehicles for content.

In most cases, the interface that uses a spatial metaphor (the window in a text editor, the control panel in a flight simulator, the bidimensional map of a website for city entertainment...) lets the user know what actions are possible and what are her possibilities for interaction immediately, since it maps knowledge from the everyday world. The metaphor defines our position within the conceptual space and the set of relevant relationships for perception, interpretation and action: we are inside/outside, we turn pages or advance through a landscape, we are included/excluded, etc.; the paper attempts a typology of these relationships. My approach is concerned with the kind of spatial metaphors that we experience in our desktop or laptop screens, conceptually determined from the start as "windows" which let us see a representation of what's happening "inside" the computer. Spatial metaphors shape the way we perceive digital environments and our relationships to them as users. The interesting thing about these metaphors is that their appeal is not related to how "faithful" they are, in fact it could be said that these metaphors' power is greater the less literal they are, the more they rely on imagination and fantasy rather than on exact reproduction. The question of how literal a metaphor is can be the key to the success of a particular interface.

The last question that the paper tackles is the relationship between spatial metaphors in interfaces and user control. Unlike what happened with previous techniques that used spatialization as an aid for thought (the Ars Memoriae techniques), where the "user" would freely create her own mental spaces; modern interfaces present the user with the spatial metaphor already set up, so that the two experiences are not immediately interchangeable as some literature seems to suggest.