Mobile Map Applications for Foldable Devices

Mobile maps, the digital evolution of traditional paper maps, have become an integral part of the daily lives of mobile device users [3, 12, 17, 19]. The functionalities offered by these applications cater to a wide range of users’ needs, including route planning for commuting or travel [8], local business search [4], real-time traffic updates [6], location sharing [18], and even augmented reality navigation [22]. Unlike traditional paper maps, digital maps can be adapted and customised to fit specific contexts, offering a unique advantage for user experience and usability [10]. Depending on the requirements, adaptations can include points of interest, highlighted areas or other information not available on paper maps, which can drastically improve the interaction [23]. However, these adaptations need to be carefully designed to avoid overwhelming the user or reducing their confidence during navigation and spatial learning [10, 13, 14]. The design of mobile map adaptations, therefore, must consider the specific user, the use case, and especially the screen size of the device. With a range of mobile devices available, from small smartwatches to large tablets, screen size plays a vital role in mobile map design [10]. Especially for smaller screens, researchers have explored ways to convert maps to fit on this smaller form factor. For instance, StripeMaps [23] replaces the two-dimensionality of a map with a linear route on small smartwatch screens to adjust the interface to fit the smaller size.

Existing foldable devices in the market, such as the Samsung Galaxy Z Flip, the Motorola razr, or the Samsung Galaxy Fold, do not only come with multiple screen sizes but also incorporate different folding mechanisms. Each offering a novel approach to provide users with more screen space. However, due to the novelty of these devices, there is currently no research or guideline for mobile map applications on foldables. To effectively design and adapt mobile maps for foldable devices, understanding the diverse ways users interact with mobile maps is crucial. As mobile maps continue to evolve, becoming more information-dense and tailored to specific user groups [16], the interaction and user behaviour grow increasingly complex. Therefore, understanding this behaviour is a critical step towards adapting mobile maps for innovative platforms such as foldable screens [17]. Even though research focusing on map interaction and user behaviour is limited, some insightful studies exist [1, 15, 17]. For instance, Savino et al. [17] unobtrusively recorded user data, thus gaining insights about natural user behaviour. The study identifies four primary states of map usage – search, place, direction, and map-view manipulation. These represent the most commonly executed actions on mobile map applications and informed the design of our context scenarios during our study.

Three photos, the first showing a Samsung Galaxy Z Fold3 5G phone running Google Maps. The following two photos display a paper prototype designed to mimic the Galaxy phone. Photo (a) shows the front view of the paper prototype, while photo (b) shows the inside of the paper prototype.

Beyond how users interact with mobile maps on traditional smartphones, the emergence of foldable screens introduces new ways of interacting with mobile maps as they offer the unique advantage of dynamically resizable screens and increased mobility. Foldwatch [5], a paper prototype developed based on an origami folding technique, explores the potential for foldable devices by unfolding smaller screens (mostly used for passive information consumption) to larger screens for more complex interactions. A similar approach could be taken with mobile map applications. FoldMe [9] proposed principles for foldable designs and explored various folding techniques for flexible devices. One highlighted feature is the double-sided design, allowing developers to utilise both display sides for enhanced access and multitasking. The study suggests folding interactions are a natural addition to established touch gestures, enhancing user experience. Lee et al. [11] indicate users prefer a mix of folding, tearing, crumpling, and conventional touch gestures when interacting with foldable devices. Ultimately, while designing for novel form factors such as foldable devices, map customisation should be highly flexible and individualised, stating that there are diverse use cases with well-defined needs [2]. Specific guidelines, like those suggested by Höök [7], can help to ensure such map adaptations don't violate usability principles and maintain user autonomy.

Therefore, in this research, we investigated the design of mobile map applications for foldable devices with nine participants using paper prototypes with different context scenarios in a lab study. Our results highlight the importance of the context; during navigation scenarios, participants preferred different map views on the inside screen and cover screen of the foldable device, while inconsistencies between screens during exploration scenarios proved confusing. Participants also appreciated keeping the map orientation aligned between the screens and the larger screen space provided by foldables.

While existing literature provides valuable insights into the functionality and user behaviour associated with mobile maps, as well as design principles for foldable screens, there remains a gap in understanding how these two intersect. Our study aims to bridge this gap by investigating the impact of foldable screen designs on user interactions in mobile map applications.

We collect qualitative and quantitative data to gain insights into device usability and user preference when adapting mobile maps for foldable devices.

2.2 Prototype

To conduct the study, we developed a paper prototype based on the Samsung Galaxy Z Fold3 5G (see Figure 1). It consists of two black-painted cardboard pieces taped together in the middle to open and close the prototype. Laminated screenshots glued to the cover and inside screen of the prototype imitate the cover and inside screen of the device. The prototype's dimensions correspond to the actual device: the inside screen is 158.2 x 128.1 x 6.4 mm in size, and the cover screen is 158.2 x 67.1 mm. The paper prototype was used to explore different map adaptions during various context scenarios.

A bar plot divided into three cells, one for each task, displaying the rank order of interface alternatives. In each cell, three bars represent first, second, and third places. The height of each bar indicates the frequency with which a particular prototype was associated with that rank for the task.

This chapter presents the results of the ranking task and the qualitative findings from the think aloud protocols.

Our study reveals that the optimal map design for foldable devices is highly dependent on the context and user preferences. In navigation-oriented tasks (task 2), the Normal prototype was less favoured, both in ranking and qualitative feedback, as it did not offer any additional utility. On the other hand, during exploration tasks (task 1), this prototype was often ranked first, and participants wanted a stronger mental correlation between the cover and the inside screen. Opinions about zoom levels were mixed during exploration tasks, but there was a general preference for mid-range zoom in both exploration and navigation scenarios. This mid-range zoom was considered to display the ‘right’ amount of information which was also somewhat personal to the different participants. Participants also expressed a desire for more relevant or personalised information and less irrelevant data, a sentiment particularly strong in the explorative parts of the study. Aligned map views were overwhelmingly preferred over unaligned ones, described as less intuitive and more irritating. This was supported by the rank orders. The preference for unaligned maps appears to stem from a minority of participants who wish to challenge their sense of orientation rather than merely follow directions.

Regarding foldable interactions, the findings were inconclusive. While some advantages over traditional pinch gestures were noted, particularly in terms of precision and time efficiency, participants also voiced reservations. The primary benefit of foldable devices was the increased screen real estate when unfolded. However, its usefulness is tied to personalisation and map designs that align with user expectations. Some participants indicated that they would prefer foldable gestures like unfold-to-zoom or unfold-to-rotate if the expanded screen displayed precisely what they desired. In essence, the success of foldable interactions as a replacement for conventional touch inputs relies on personalisation and contextual utility.

Our results underscore the role and importance of context in mobile map interactions on foldable devices. The study identifies key areas such as map alignment, zoom level, and user interface gestures, thereby contributing to an understanding of the challenges and opportunities for future design strategies in foldable mobile map applications. Participants differentiated between navigational and exploratory scenarios, showing a preference for different map views on the foldable device's screens. Our results suggest that designers should consider the context when determining map features and that personalisation becomes especially important in exploratory scenarios, presenting a design opportunity to adjust, for example, zoom levels based on user behaviour or settings.

Though foldable interactions were appreciated for their efficiency and precision, participants generally favoured conventional pinch-to-zoom and pinch-to-rotate gestures. This may be attributed to familiarity, highlighting the importance of user adaptation over time, as foldable technology becomes more mainstream. Furthermore, participants highly valued the larger screen space offered by foldables. The foldable device's larger screen offers more room for displaying important information like Points of Interest (POIs), landmarks, and potentially even advertisements. While our study focuses specifically on foldable devices, our results show that personalisation and context-specific behaviour are what users expect from a next-generation mobile map application. Foldable devices are in a particularly interesting position regarding this potential development as the multiple screens these devices provide can be used flexibly instead of the static behaviour they show today.