Multiplex encoding in multi-layer

visualisationsSimon Walton, Oxford e-Research Centre

Overview

• Multilayer visualisations; emphasis on cartography

• Multiplexing as a possible solution

Map Overlays

Charles Booth John Snow

Map Overlays

- McHarg (1971)

“...let us map physiographic factors so that the darker the tone, the greater the cost. Let us similarly map social values so that the darker the tone, the higher the value. Let us make the maps transparent. When these are superimposed, the least-social-cost areas are revealed by the lightest tone.”

The Role of Visual Perception

• Most cartographic works use ‘perception’ with more emphasis on aesthetic qualities rather than visual understanding

• Who is the target of the visualisation?

• Public visual communication; vs

• Private visual thinking

Using spatial frequency

Dali

Conclusion

• Layered visualisations largely an unsolved problem

• A layered visualisation can be `modulated’ to assist user’s visual decomposition of each layer

• Not enough emphasis on visual perception theory in cartography / GIS