Reducing visual clutter on dynamic 3D flow maps
Summary
Visual clutter is an obstruction of map objects that reduces the usability of flow maps. A visualization of a flow map in a 3D environment as well as a dynamic navigation capability is creating new design opportunities. In this research, a usability test is conducted on two 3D display environments - a PC screen and an iPad in combination with mixed reality (MR) - and two cartographic styling choices - line volume and height - of flow maps for investigating the potential effects on reducing visual clutter. A qualitative method is used for exploratory and descriptive research. Usability is measured by comparing the efficiency, effectiveness and satisfaction with a questionnaire and interview. Additionally, the participants are asked to speak out their observations by using a think aloud method which is traced by written notes and audio recording. At the finalizing stage of the usability test design, a focus group session with experts is performed for collecting final feedback, followed by three pilot tests. The final usability test starts with a familiarization phase for training the participants with the hardware and software, followed by the main test, a questionnaire in correspondence to the flow maps and ends with a satisfaction interview at the final stage of the test. It is concluded that the maps displayed in the PC environment have scored a better usability than for the MR maps, and the usability of the maps with a flow volume symbology is better than height. Although MR can enable new visualization opportunities, the usability of a flow map does not automatically improve when compared to the same 3D map displayed on a PC screen.