Fusion of visual channels

In this chapter, we consider the need in multifield visualization to depict information contained in two or more fields in a compositional manner. There are many different visual channels, some of which are more commonly seen in visualization than others. Channel fusion occurs when two or more visual entities have to share the same screen space. By applying appropriate constructive operations on visual channels in the composition, one may encode the integration as well as separation of the underlying information depicted by the original channels. One special situation is where multiple fields are a set of fields from different temporal steps, which imposes additional constraints on the use of visual channels. It is inevitable that the availability of visual channels will not be able to scale up to a large number of visual channels. Hence, we consider briefly several general-purpose data mapping methods that can be used to reduce the complexity of visual mapping.