Andreas Hall

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.

Knowledge and Reasoning in Spatial Analysis

Reasoning is an essential part of any analysis process. Especially in visual analytics, the quality of the results depends heavily on the knowledge and reasoning skills of the analyst. In this study, we consider how to make the results transparent by visualizing the reasoning and the knowledge, so that persons from outside can trace and verify them. The focus of this study is in spatial analysis and a case study was carried out on a process of off-road mobility analysis. In the case study, linked views of a map and a PCP were identified as reasoning artifacts. The knowledge used by the analyst was formed by these artifacts and the tangible pieces of information identified in them, along with the mental models of the analyst′s mind. To make the results transparent, the tangible pieces of information were marked with sketches and the mental models were presented in causal graphs because it was found that causality was central to the reasoning process in the case study. The causal graph allows the reasoning of the analyst to be studied, as well as traced back to its origin.

Visualizing the workings of agent-based models: Diagrams as a tool for communication and knowledge acquisition

Abstract One of the biggest challenges in developing agent-based models (ABMs) is the acquisition of domain knowledge. Interviews, or other types of face-to-face communication, are one of the ways of doing it but problems might arise if we deal with tacit knowledge and if the interviewer and the interviewee come from a very different cultural and educational background. This research proposes a visualization approach to be used in the interaction between domain and modeling experts that will facilitate communication in these kinds of situations. The approach is based on the findings of knowledge visualization and related fields, as well as on a firm understanding of ABMs. Three important aspects of ABMs that need to be visualized in order to facilitate understanding were identified. In a case study, performed in relation to a project where a spatial ABM was developed, three node-link diagrams were created according to the developed approach. They visualize the conceptual structure, the simulation process, and the data model of the ABM. These diagrams were positively received by the stakeholders of the project and they improved workflow and communication in the project.

Analysis of Basic Relations Within Insights of Spatio-Temporal Analysis

Studying human reasoning in interaction with visual analytics tools is an important part of visual analytics research. This case study contributes to the field by investigating the role that the basic spatial and temporal relations play in the analytical reasoning process. After a thorough literature review a case study was performed that applies reverse engineering and introspection as its research methods. In the case study the link between the basic spatio-temporal relations and human qualitative reasoning was explored by means of the dissection of four insights reached by an analyst watching a simple animated map. The results of the case study support the hypothesis showing that insight can be broken down to, and derived from, the level of basic relations. At the same time, the important role of the reference system and the previous knowledge of the analyst became evident.

Insight provenance for spatiotemporal visual analytics: Theory, review, and guidelines

Research on provenance, which focuses on different ways to describe and record the history of changes and advances made throughout an analysis process, is an integral part of visual analytics. This paper focuses on providing the provenance of insight and rationale through visualizations while emphasizing, first, that this entails a profound understanding of human cognition and reasoning and that, second, the special nature of spatiotemporal data needs to be acknowledged in this process. A recently proposed human reasoning framework for spatiotemporal analysis, and four guidelines for the creation of visualizations that provide the provenance of insight and rationale published in relation to that framework, work as a starting point for this paper. While these guidelines are quite abstract, this paper set out to create a set of more concrete guidelines. On the basis of a review of available provenance solutions, this paper identifies a set of key features that are of relevance when providing the provenance of insight and rationale and, on the basis of these features, produces a new set of complementary guidelines that are more practically oriented than the original ones. Together, these two sets of guidelines provide both a theoretical and practical approach to the problem of providing the provenance of insight and rationale. Providing these kinds of guidelines represents a new approach in provenance research.

Comparison of Temporally Classified and Unclassified Map Animations

While animation is a natural and, under certain circumstances, effective way to present spatio-temporal information, it has its limitations. Studying animations of large point datasets can be cognitively very demanding. Aiming to help users to comprehend such data, this study presents a new concept of temporal classification. A phenomenon is classified into periods of increasing, decreasing, and steady intensity, and each is assigned different colours in an animation. This concept was tested with a group of experts in the field of the phenomenon. The results suggest that this kind of classified animation, together with a traditional animation presenting the same dataset, supports users in their analysis process and adds to the impression they get of the phenomenon. It also seems that the viewing order of the animations matters: the full potential of the tested method is reached by viewing the traditional version first and temporally classified version after that.

An experimental analysis of three methods for highlighting colorful pictographic symbols

Highlighting is one of the key functionalities of any interactive visualization environment. Yet, there is little research on highlighting methods. This article focuses on highlighting of colorful pictographic symbols. Three strategies for highlighting were tested by implementing three highlighting methods that were suggested suitable in the literature on attention, perceptual grouping, and motion detection. An experimental design measuring response times and accuracy was used and subjective opinions were collected. The three available strategies for applying the highlighting effect to a subset of visually salient (i.e., colorful) symbols are: (1) to decrease the saliency of the non-highlighted symbols, (2) to increase the saliency of the highlighted symbols, and (3) to add a connecting element for grouping the highlighted symbols. Of these strategies, adding a connecting element was found to be the least efficient based on the response times, whereas both methods for tuning the saliency difference between the highlighted and non-highlighted symbols were found to be equally efficient. However, decreasing the saliency of the non-highlighted symbols was clearly preferred in the subjective evaluation.