Complexity and Salience: Evaluating the Inter-Scene Variability of Animated Choropleth Maps

Animated choropleth maps allow for the compilation of potentially massive time-series datasets which can portray space-time change in a congruent manner. They are also becoming increasingly common for data visualization. When users view and interact with these maps, however, there is the likelihood that the human cognitive-perceptual system may be overwhelmed by a large number of simultaneous changes in each scene: this so-called `change blindness\u27 is a common malady when viewing successive scenes, unless scene-to-scene graphical changes are salient enough to attract the fixation of the user. Even then, there may be a limit to the number of simultaneous changes that the user can perceive. This thesis examined the saliency of change occurring in map features by conducting a human-subjects study to explore the effect of intensity, number and pattern of change-clusters on a map user\u27s ability to detect change. These characteristics can be quantified for a given animated choropleth map using a localized change metric, Magnitude of Change. This study found that, for generalized choropleth maps, clusters in which at least 80% of the polygons changed class were significantly more likely to be successfully detected than clusters with lower levels of class change; additionally, users performed more poorly with maps containing single clusters than for those with multiple clusters. There were no differences in accuracy for gender, or for whether or not the user played video games regularly, but domain expertise (i.e., having taken a prior geography class) had a positive effect on accuracy. It appears that, for maximum effectiveness, animated choropleth maps should consist of limited datasets, and be made simpler and more user-friendly

Detection of moving point symbols on cartographic backgrounds

The present paper presents the performance of an experimental cartographic study towards the examination of the minimum duration threshold required for the detection by the central vision of a moving point symbol on cartographic backgrounds. The examined threshold is investigated using backgrounds with discriminant levels of information. The experimental process is based on the collection (under free viewing conditions) and the analysis of eye movement recordings. The computation of fixation derived statistical metrics allows the calculation of the examined threshold as well as the study of the general visual reaction of map users. The critical duration threshold calculated within the present study corresponds to a time span around 400msec. The results of the analysis indicate meaningful evidences about these issues while the suggested approach can be applied towards the examination of perception thresholds related to changes occurred on dynamic stimuli

A Raster-Based Neighborhood Model for Evaluating Complexity in Dynamic Maps

ABSTRACT: The cartographic community has taken a renewed interest in evaluating the effectiveness of automated map displays, given their increasing prevalence among general map users. The changing values of the mapped area from frame to frame in a dynamic thematic map constitute its main element of visual complexity, while many of the peripheral map components often change little (titles) or not at all (scale bars, color ramps). Building on recent research into visual complexity as it relates to dynamic thematic mapping, this study developed a raster-based GIS model for evaluating the graphical variability between sequences of choropleth maps as they would appear as scenes in a dynamic map. The evaluation of visual complexity is based on two previously established metrics, Basic Magnitude of Change (BMOC) and Magnitude of Rank Change (MORC), for describing the variability and average class 'jump' for enumeration units across map scenes. The model presented in this paper uses a neighborhood focal operator that sequentially moves across the entire map, replicating the user's viewing perspective as it divides the scene to instantaneously focus only on the part of the map within the foveal viewing area, a zone of enhanced visual-cognitive acuity. This model accepts a single vector map, uses its class membership attribute data as inputs, computes the BMOC and MORC variability, and writes the value to the focus. The model output is two smoothed map images depicting relative visual complexity values for the sequence of maps. While the neighborhood paradigm can theoretically be used to quantify change on either a vector or raster map, the raster-based approach suggests several improvements over one based on vector polygons. These include a potentially higher degree of accuracy in modeling the user's perspective, especially if enumeration units vary widely in size within the foveal area and map itself, plus the ability to use (with minimal customization) existing image-processing software such as ERDAS Imagine, ArcGIS Spatial Analyst and ENVI to perform analysis of dynamic map complexity

Survey on geographic visual display techniques in epidemiology: Taxonomy and characterization

Many works have been done on the topic of Geographic Visual Display with different objectives and approaches. There are studies to compare the traditional cartography techniques (the traditional term of Geographic Visual Display (GVD) without Human-Computer Interaction (HCI)) to Modern GIS which are also known as Geo-visualization, some literature differentiates and highlight the commonalities of features and architectures of different Geographic Visual Display tools (from layers and clusters to dot and color and more). Furthermore, with the existence of more advanced tools which support data exploration, few tasks are done to evaluate how those tools are used to handle complex and multivariate spatial-temporal data. Several test on usability and interactivity of tools toward user's needs or preferences, some even develop frameworks that address user's concern in a wide array of tasks, and others prove how these tools are able to stimulate the visual thought process and help in decision making or event prediction amongst decision-makers. This paper surveyed and categorized these research articles into 2 categories: Traditional Cartography (TC) and Geo-visualization (G). This paper will classify each category by their techniques and tasks that contribute to the significance of data representation in Geographic Visual Display and develop perspectives of each area and evaluating trends of Geographic Visual Display Techniques. Suggestions and ideas on what mechanisms can be used to improve and diversify Geographic Visual Display Techniques are provided at the end of this survey

Measuring the Effectiveness of Static Maps to Communicate Changes over Time

Both in digital and print media, it is common to use static maps to show the evolution of values in various regions over time. The ability to communicate local or global trends, while reducing the cognitive load on readers, is of vital importance for an audience that is not always well versed in map interpretation. This study aims to measure the efficiency of four static maps (choropleth, tile grid map and their banded versions) to test their usefulness in presenting changes over time from a user experience perspective. We first evaluate the effectiveness of these map types by quantitative performance analysis (time and success rates). In a second phase, we gather qualitative data to detect which type of map favors decision-making. On a quantitative level, our results show that certain types of maps work better to show global trends, while other types are more useful when analyzing regional trends or detecting the regions that fit a specific pattern. On a qualitative level, those representations which are already familiar to the user are often better valued despite having lower measured success rate

The cartography of time-changing phenomena: the animated map

This research examines the role of the animated film in the portrayal of time series data, specifically change in the British population. It concentrates on cartographic animation and first reviews techniques developed thus far for computer-animated generation of maps for films. In order to generate an animated film, time; series data is first needed. Existing sources of time series data are shown to contain serious deficiencies for this purpose, and thus a new set of population data is generated for Britain throughout the period 1901 - 1971, and based on the Census. Ways of presenting change in this data set are then examined. Conventional methods of measuring change in the population, whilst satisfactory in static cartography, have definite limitations when used in animated cartography. Two methods, based on population density and on expected change in the population, are developed and the results mapped. As with conventional methods of measuring change, standard cartographic techniques may not be used in animated filming with any degree of success, and the resultant film shows significant departures from accepted cartographic theory. The method of film production is then examined, from the compilation of the maps themselves, through the use of the microfilm plotter in generation of the film, to the final sound tracking. The resultant film is enclosed with the thesis; the final chapter examines the success of this film. Whilst significant imperfections are shown in this example, it is concluded that the animated film has a role to play in the portrayal of time series data

Techniques for augmenting the visualisation of dynamic raster surfaces

Despite their aesthetic appeal and condensed nature, dynamic raster surface representations such as a temporal series of a landform and an attribute series of a socio-economic attribute of an area, are often criticised for the lack of an effective information delivery and interactivity.In this work, we readdress some of the earlier raised reasons for these limitations -information-laden quality of surface datasets, lack of spatial and temporal continuity in the original data, and a limited scope for a real-time interactivity. We demonstrate with examples that the use of four techniques namely the re-expression of the surfaces as a framework of morphometric features, spatial generalisation, morphing, graphic lag and brushing can augment the visualisation of dynamic raster surfaces in temporal and attribute series

Choriented Maps: Visualizing SDG Data on Mobile Devices

Choropleth maps and graduated symbol maps are often used to visualize quantitative geographic data. However, as the number of classes grows, distinguishing between adjacent classes increasingly becomes challenging. To mitigate this issue, this work introduces two new visualization types: choriented maps (maps that use colour and orientation as variables to encode geographic information) and choriented mobile (an optimization of choriented maps for mobile devices). The maps were evaluated in a graphical perception study featuring the comparison of SDG (Sustainable Development Goal) data for several European countries. Choriented maps and choriented mobile visualizations resulted in comparable, sometimes better effectiveness and confidence scores than choropleth and graduated symbol maps. Choriented maps and choriented mobile visualizations also performed well regarding efficiency overall and performed worse only than graduated symbol maps. These results suggest that the use of colour and orientation as visual variables in combination can improve the selectivity of map symbols and user performance during the exploration of geographic data in some scenarios.Comment: Accepted for publication in the Cartographic Journa

Recent Computer Technologies for an Innovative Cartographic Language: Espon Cartographic Language, Interim Report 1

Review of the state of the art in recent computer technologies and related cartographic software in support of ensuring an innovative cartographic language. The service provider is asked to review the state of the art in recent computer technologies and related cartographic software development in support of ensuring an innovative cartographic language. The service provider shall, based on this review, present options for modernising the ESPON Cartographic Language. The fulfilment of this task should not be limited only to more “traditional” cartography, but explore new options for adding new cartographic concepts, types of illustrations and computer animated presentations, that could support the presentation of the geography of policy orientations and forward-looking territorial evidence to the European territorial policy arena. The review shall lead to recommendations of cartographic technologies and techniques to consider in a modernised ESPON Cartographic Language. It shall be used as input for recommendations on new cartographic elements to consider in a modernised ESPON Cartographic Language under task 4 and 5. Three dimensions for an Innovative cartographic language will be explored in three directions:- Former Semiotic language combined with new technologies- Usability of the produced representations - Focus on added dimensions like interactivity, animation, multimedia, 3D, etc

Comparing Different Levels of Interactivity in the Visualization of Spatio-Temporal Data

The Internet and other advances in technology have dramatically affected cartography in recent decades and yet these new capabilities have not been adequately evaluated for effectiveness. Are dynamic maps more effective than traditional static paper maps in allowing users to visualize spatio-temporal patterns? How important is a higher level of interactivity in visualizing data? Which format is preferred? To examine these questions, human subject tests were conducted to evaluate different levels of interactivity as represented by 1) a static paper map series; 2) an animated map with \u27VCR\u27-type controls; and 3) a toggle map featuring an interactive temporal legend. Results indicate that while the level of interactivity did not affect accuracy of answers to questions regarding spatio-temporal patterns, the total amount of time in which these questions were answered lessened as the level of interactivity increased. Overall, test subjects were more enthusiastic towards the tools featuring greater interactivity