Point feature label placement for multi-page maps on small-screen devices

• Published in: Computers & graphics 2021-11, Vol.100, p.66-80
• Main Authors: Gedicke, Sven, Jabrayilov, Adalat, Niedermann, Benjamin, Mutzel, Petra, Haunert, Jan-Henrik
• Format: Article
• Language: English
• Subjects: Consistent labeling; Electronic devices; Graph coloring; Icons; Interactive maps; Labels; Map labeling; Optimization; Partial ordering; Query processing; Smartphones; Smartwatches; Spatial data; Zooming
• ISSN: 0097-8493; 1873-7684
• DOI: 10.1016/j.cag.2021.07.019

•Two-phase strategy for labeling small-screen maps with multiple pages.•Assignment of labels to pages in off-line phase via mathematical programming.•Retrieval of labels for selected map extent and page in interactive phase.•The user can navigate from page to page and thus retrieve many labels without zooming.•When the user pans the map the labeling is temporally consistent. [Display omitted] Map applications on mobile devices such as smartphones and smartwatches have become ubiquitous. When visualizing spatial data on such small-screen devices, one major challenge is annotating the data with labels (e.g., small icons). The restricted space requires new visualization techniques as established strategies, such as maximizing the number of placed labels, easily lead to the omission of information. We propose an approach that distributes all labels contained in a temporarily fixed map section on multiple pages. Applying interaction techniques for navigating through the pages, a user can access all information both without any overlapping labels and without the need for zooming. We propose a method with two phases; a pre-processing phase and a query phase. We use an optimization approach to pre-compute labelings on the level of a whole city and provide the on-demand querying of individual labelings at a more local level. Our approach provides a consistent label-page assignment, meaning that labels do not appear and disappear when the user pans the map. Further, our model provides quick access to important information and a spatially balanced distribution of labels on pages. In experiments on real-world data we analyze different parameter settings and show that our model yields high-quality labelings.