The modes of interaction (e.g., mouse and touch) between maps and users affect the effectiveness and efficiency of transmitting cartographic information. Recent advances in eye tracking technology have made eye trackers lighter, cheaper and more accurate, broadening the potential to interact with maps via gaze. In this study, we focused exclusively on using gaze to choose map features (i.e., points, polylines and polygons) via the select operation, a fundamental action preceding other operations in map interactions. We adopted an approach based on the dwell time and buffer size to address the low spatial accuracy and Midas touch problem in gaze-based interactions and to determine the most suitable dwell time and buffer size for the gaze-based selection of map features. We conducted an experiment in which 38 participants completed a series of map feature selection tasks via gaze. We compared the participants’ performance (efficiency and accuracy) between different combinations of dwell times (200 ms, 600 ms and 1000 ms) and buffer sizes (point: 1°, 1.5°, and 2°; polyline: 0.5°, 0.7° and 1°). The results confirmed that a larger buffer size raised efficiency but reduced accuracy, whereas a longer dwell time lowered efficiency but enhanced accuracy. Specifically, we found that a 600 ms dwell time was more efficient in selecting map features than 200 ms and 1000 ms but was less accurate than 1000 ms. However, 600 ms was considered to be more appropriate than 1000 ms because a longer dwell time has a higher risk of causing visual fatigue. Therefore, 600 ms supports a better balance between accuracy and efficiency. Additionally, we found that buffer sizes of 1.5° and 0.7° were more efficient and more accurate than other sizes for selecting points and polylines, respectively. Our results provide important empirical evidence for choosing the most appropriate dwell times and buffer sizes for gaze-based map interactions.
