A computer hard- and software system designed to support Otto Neurath's Isotype methodology (see [Neur36], [Neur46] or [HaKi91]) has to meet a number of different requirements which roughly belong to two categories. The first category contains all requirements regarding the technical aspects of the user interface (see [HaHi89]) as well as the quality of the resulting printouts (i.e., printer resolution, precision, colour set, ...). The second category lies beyond Pure computer science considerations and is closely related to Neurath's rule base used to define semantically correct Isotype charts. All considerations aiming at the technical quality of the produced output or on user-friendly interfaces are more or less common to all graphic editors. However, the topics belonging to the second category are specific to the Isotype methodology and therefore motivate the design and implementation of an Isotype chart editor.