Arzu Çöltekin

Evaluating the Effectiveness of Interactive Map Interface Designs: A Case Study Integrating Usability Metrics with Eye-Movement Analysis

This paper proposes combining traditional usability methods with the analysis of eye movement recordings to evaluate interactive map interfaces, and presents a case study in support of this approach. The case study evaluates two informationally equivalent, but differently designed online interactive map interfaces presented to novice users. In a mixed factorial experiment, thirty participants were asked to solve three typical map-use tasks using one of the two interfaces; we then measured user satisfaction, efficiency (completion time) and effectiveness (accuracy) with standard SEE usability metrics. While traditional (bottom line) usability metrics can reveal a range of usability problems, they may be enhanced by additional procedural measures such as eye movement recordings. Eye movements have been shown to help reveal the amount of cognitive processing a display requires and where these cognitive resources are required. Therefore, we can establish how a display may or may not facilitate task completion by analyzing eye movement recordings. User satisfaction information related to tested stimuli (i.e., collected through standardized questionnaires) can also be linked to eye tracking data for further analysis. We hope that the presented methodology and case study will help cartographers and map interface designers to better identify design issues in their products, and that these insights will eventually lead to more effective and efficient online map interfaces.

Foveated gaze-contingent displays for peripheral LOD management, 3D visualization, and stereo imaging

Advancements in graphics hardware have allowed development of hardware-accelerated imaging displays. This article reviews techniques for real-time simulation of arbitrary visual fields over still images and video. The goal is to provide the vision sciences and perceptual graphics communities techniques for the investigation of fundamental processes of visual perception. Classic gaze-contingent displays used for these purposes are reviewed and for the first time a pixel shader is introduced for display of a high-resolution window over peripherally degraded stimulus. The pixel shader advances current state-of-the-art by allowing real-time processing of still or streamed images, obviating the need for preprocessing or storage.

Visual exploration of eye movement data using the space-time-cube

Eye movement recordings produce large quantities of spatiotemporal data, and are more and more frequently used as an aid to gain further insight into human thinking in usability studies in GIScience domain among others. After reviewing some common visualization methods for eye movement data, the limitations of these methods are discussed. This paper proposes an approach that enables the use of the Space-Time-Cube (STC) for representation of eye movement recordings. Via interactive functions in the STC, spatio-temporal patterns in eye movement data could be analyzed. A case study is presented according to proposed solutions for eye movement data analysis. Finally, the advantages and limitations of using the STC to visually analyze eye movement recordings are summarized and discussed.

Towards (Re)Constructing Narratives from Georeferenced Photographs through Visual Analytics

Abstract We present a study that explores methodological steps towards (re)constructing collective narratives from the photo-taking behaviour of two groups (foreign tourists and inhabitants of Switzerland) by analysing spatial and temporal patterns in user-contributed, georeferenced photographs of Zurich, Switzerland. We reason that the photographers typically capture a scene or a moment because they want to remember or share it, thus these scenes or moments are meaningful to them. Various scholars suggest that the human experience (i.e. this meaningfulness) is what separates a place from the mathematical descriptions of space. While this notion is well known in larger geographic literature, it is under-explored in cartographic research. We respond to this research gap and reconstruct static and dynamic patterns of photo-taking and -sharing behaviour to assist in capturing the implicit meaning in the studied locations. These locations may be meaningful to only a certain group of people in certain moments; therefore, studying group differences in spatial and temporal photo-taking patterns will help building a collective and comparative story about the studied place. In our study, we focus on experiences of foreign versus domestic visitors, and in the process, we examine the potential (and feasibility) of georeferenced photographs for extracting such collective narratives using qualitative and quantitative visual analytical methods.

An Empirical User Study for Measuring the Influence of Colour Distance and Font Size in Map Reading Using Eye Tracking

The primary goal of this study is to empirically analyse the influence of colour distance and font size on map readability. We utilized eye-tracking to complement the classical usability metrics; thus, we studied performance metrics such as effectiveness (i.e. success, accuracy), efficiency (i.e. time to answer, task completion time), and selected eye tracking metrics fixation frequency, fixation duration and scanpath speed as well as conducting an area-of-interest (AOI) analysis to understand the performance and strategy issues that may be influenced by colour distance and font size during map reading. The user experiment was carried out in a controlled laboratory where participants were asked to conduct a visual search task and mark the correct answer with a mouse click on a static map on a computer screen. Collected data was analysed through descriptive and inferential statistics. Task completion times for the five tested colour distances show that as the colour distances grow larger, the relative differences in task completion times become statistically significant; empirically confirming our intuition that larger colour distances are better for map readability. The comparison of the scanpath speeds for the tested font sizes suggests that the medium font size leads to a more efficient search.

High Quality Geographic Services and Bandwidth Limitations

In this paper we provide a critical overview of the state of the art in human-centric intelligent data management approaches for geographic visualizations when we are faced with bandwidth limitations. These limitations often force us to rethink how we design displays for geographic visualizations. We need ways to reduce the amount of data to be visualized and transmitted. This is partly because modern instruments effortlessly produce large volumes of data and Web 2.0 further allows bottom-up creation of rich and diverse content. Therefore, the amount of information we have today for creating useful and usable cartographic products is higher than ever before. However, how much of it can we really use online? To answer this question, we first calculate the bandwidth needs for geographic data sets in terms of waiting times. The calculations are based on various data volumes estimated by scholars for different scenarios. Documenting the waiting times clearly demonstrates the magnitude of the problem. Following this, we summarize the current hardware and software solutions, then the current human-centric design approaches trying to address the constraints such as various screen sizes and information overload. We also discuss a limited set of social issues touching upon the digital divide and its implications. We hope that our systematic documentation and critical review will help researchers and practitioners in the field to better understand the current state of the art.

User studies in cartography : opportunities for empirical research on interactive maps and visualizations

ABSTRACT The possibility of digital interactivity requires us to reenvision the map reader as the map user, and to address the perceptual, cognitive, cultural, and practical considerations that influence the user’s experience with interactive maps and visualizations. In this article, we present an agenda for empirical research on this user and the interactive designs he or she employs. The research agenda is a result of a multi-stage discussion among international scholars facilitated by the International Cartographic Association that included an early round of position papers and two subsequent workshops to narrow into pressing themes and important research opportunities. The focus of our discussion is epistemological and reflects the wide interdisciplinary influences on user studies in cartography. The opportunities are presented as imperatives that cross basic research and user-centered design studies, and identify practical impediments to empirical research, emerging interdisciplinary recommendations to improve user studies, and key research needs specific to the study of interactive maps and visualizations.

Prevalence of the terrain reversal effect in satellite imagery

The terrain reversal effect is a perceptual phenomenon which causes an illusion in various 3D geographic visualizations where landforms appear inverted, e.g. we perceive valleys as ridges and vice versa. Given that such displays are important for spatio-visual analysis, this illusion can lead to critical mistakes in interpreting the terrain. However, it is currently undocumented how commonly this effect is experienced. In this paper, we study the prevalence of the terrain reversal effect in satellite imagery through a two-stage online user experiment. The experiment was conducted with the participation of a diverse and relatively large population (n = 535). Participants were asked to identify landforms (valley or ridge?) or judge a 3D spatial relationship (is A higher than B?). When the images were rotated by 180°, the results were reversed. In a control task with ‘illusion-free’ original images, people were successful in identifying landforms, yet a very strong illusion occurred when these images were rotated 180°. Our findings demonstrate that the illusion is acutely present; thus, we need a better understanding of the problem and its solutions. Additionally, the results caution us that in an interactive environment where people can rotate the display, we might be introducing a severe perceptual problem.

Not all anxious individuals get lost: trait anxiety and mental rotation ability interact to explain performance in map-based route learning in men

Navigation through an environment is a fundamental human activity. Although group differences in navigational ability are documented (e.g., gender), little is known about traits that predict these abilities. Apart from a well-established link between mental rotational abilities and navigational learning abilities, recent studies point to an influence of trait anxiety on the formation of internal cognitive spatial representations. However, it is unknown whether trait anxiety affects the processing of information obtained through externalized representations such as maps. Here, we addressed this question by taking into account emerging evidence indicating impaired performance in executive tasks by high trait anxiety specifically in individuals with lower executive capacities. For this purpose, we tested 104 male participants, previously characterised on trait anxiety and mental rotation ability, on a newly-designed map-based route learning task, where participants matched routes presented dynamically on a city map to one presented immediately before (same/different judgments). We predicted an interaction between trait anxiety and mental rotation ability, specifically that performance in the route learning task would be negatively affected by anxiety in participants with low mental rotation ability. Importantly, and as predicted, an interaction between anxiety and mental rotation ability was observed: trait anxiety negatively affected participants with low-but not high-mental rotation ability. Our study reveals a detrimental role of trait anxiety in map-based route learning and specifies a disadvantage in the processing of map representations for high-anxious individuals with low mental rotation abilities.

The effect of spatial distance on the discriminability of colors in maps

ABSTRACT The spatial distance (gap) between map symbols can have a great impact on their discriminability, however, there is little empirical evidence to establish spatial and attribute thresholds. In this paper, we examine the effect of the spatial gap in discriminability of color hue and value, that is, we conducted an online study to obtain performance metrics; then an eye-tracking study to understand participants’ strategies and cognitive processes. Participants completed two experimental tasks (compare two areas and decide if their color is the same; and compare three areas and rank them from the lightest to the darkest). The color distances and the spatial distances were strictly controlled for the compared areas. Our analyses confirmed that, overall, increasing the gap between colors has a consistent negative impact on the ability to differentiate them with both sequential and qualitative schemes. Furthermore, we observed that sequential schemes require larger color distances than qualitative schemes for discriminability. Finally, our results suggested that for qualitative colors, the largest tested color distance ∆E00 = 10 yields considerably higher levels of accuracy in color discrimination (even when the spatial gap between the two colors is large), thus we recommend ∆E00 = 10 to practicing cartographers and other information visualization designers.