Graphic and tabular displays are analysed under a common , unified form-relational information displays (RIDs) , which are displays that represent relations between dimensions . First , the mapping between the represented and the representing dimensions of RIDs is analysed from the perspective of distributed representations (Zhang & Norman , 1994) . Second , the structures of RIDs are analysed at three levels : dimensionality , scale types , and dimensional representations . From this analysis , a representational taxonomy is developed that not only can classify all RIDs but also can serve as a framework for systematic studies of RIDs . Third , a task taxonomy of RIDs is developed , which can classify the majority of dimension-based display tasks . Finally , the relation between representations of displays and structures of tasks is analysed in terms of a mapping principle : the information perceivable from a RID should exactly match the information required for the task . Thus , although there are no best displays that are ef ficient for all types of tasks , there is a correct or incorrect mapping between the representation of a display and the structure of a task .