In the past, the design of Geographic Information Systems (GIS) has been investigated in a bottom-up manner. At the same time, little consideration has been paid to those system components with which users have immediate contact such as languages to query spatial objects, or the user interface. Considerations about the interaction between the users and spatial data are of primary importance for these issues. The domain of this paper is the investigation of interactive spatial query languages that allow users to pose ad hoc queries against a geographic information system. Its motivation has been the observation that traditional database query languages are insufficient for the treatment of spatial properties. Deficiencies observed include the disregard of user concerns and the lack of support for renderings of query results in forms other than text. This paper presents a methodology for the design of interactive spatial query languages which are embedded into a human interface. The methodology is based upon the users' interactions with spatial objects, which are graphically rendered on a screen, and their pertinent operations. Objects and operations are provided at the conceptual level of the user interface and complemented by the selection of appropriate techniques to interact with spatial objects rendered on a screen. A number of spatial concepts are presented which are crucial for the design of a GIS query language. In a series of interface snapshots their incorporation into a human interface is presented, simulating the interaction between a user and a GIS.