Comprehension of complex or voluminous data is handicapped by a reliance on the catalogue or 'laundry-list' approach of linear, successive itemization. Mnemonic systems and other memory or machine retrieval techniques in effect are merely tricks that allow for subject and data apprehension, but not necessarily for comprehension, as this involves a representation of relationships among data. Successive items on a vertical list may indicate mutually exclusive classes, or with indentation or numbering, classes within classes within classes, but they cannot contain much more than a name and a class relationship. The considerable intellectual and financial investment in the hardware and software of non-image oriented computerized information systems makes it unlikely that any useful link to image manipulating systems (including map-generating devices) can be established. Parallel systems may well be developed which fragment what should be an integrated approach.