Design space structure

A framework characterising how raw information is organised within a design space. Nesbitt classifies information conveyed through sensory channels as nominal (categorical, such as labels), quantitative (measurable, subdivided into temporal, spatial, and geographical), and ordered (sequential). Each category of information is expressed as a spatial substrate augmented with marks, properties, and temporal encodings. This structural framework is useful for understanding how content can be translated between design spaces for accessibility. For example, a bar chart presents quantitative information spatially in the visual design space; adapting this for a blind user requires re-expressing that spatial-quantitative structure in the sonic design space, perhaps as a data table read aloud or as sonification where pitch represents value.