Comparison of font size and background color strategies for tag weights on tag maps

Tag weight differences in tag maps are usually reflected by different font sizes. With this strategy, low weighted tags may be ignored and tag sizes may be misjudged due to differing word length, character height and word width. To address these shortcomings, this paper improves the layout method of tag maps by presetting anchor points. We construct weight contours based on corner points and center points of tag outer envelope rectangles and adopt hypsometric tinting as background color to reflect tag weight differences. Finally, we compare and analyze the background color strategy with the font size strategy from the perspectives of tag selection, tag recognition, tag recall, confidence, readability, and preference through eye movement experiments and questionnaire surveys. The results show that both strategies exhibit advantages (when tags are devoid of semantics), with the font size strategy being favored slightly in this abstract case. We provide tag map designers with a new visualization scheme for the expression of tag weight.