Visualizing Method-Produced Uncertainty in Isometric Mapping

Abstract

Isometric mapping, while highly uncertain, continues to be a preferred mapping method for continuous data in many of the physical and social sciences. Isometric method-produced uncertainty refers to the various map representations that result when different methods and/or specifications are used in the mapping process. This paper examines ways to communicate the nature and magnitude of isometric method-produced uncertainty to map readers so that they are encouraged to be uncertain when it is warranted. As a case study, we consider an extensive set of plant hardiness zone maps that result when different interpolation methods and sampling resolutions operate on the same set of data. Our results show that slightly different choices in the mapping process can result in very different looking isometric maps, and suggest that the manifestations of method-produced uncertainty are not as systematic, or straightforward, as suggested by interpolation accuracy assessments. We then explore the use of two existing visualization techniques, flickering and transparency, to communicate the nature and magnitude of isometric method-produced uncertainty.