Ecological interface design (EID) is an approach to designing user interfaces that is based on the objective of providing functional system relationships to users in ways that reduce perceptual load. While EID has strong methods for determining the needed functional relationships through the analytical methods of Cognitive Work Analysis (Vicente, 1999), relatively little attention has been paid to establishing the design mappings that reduce perceptual load. We propose that different kinds of information should be assessed for perceptual fit to various modalities. In particular, those mappings that combine appropriate forms of reference with strong perceptual affordances will likely be the most successful. A case study applying this approach to the design of a multimodal ground control station for uninhabited aerial vehicle control is discussed.