Assessing map-reading skills using eye tracking and bayesian structural equation modelling

Abstract: Map reading is an important skill for acquiring spatial information. Previous studies have mainly used results-based assessments to learn about map-reading skills. However, how to model the relationship between map-reading skills and eye movement metrics is not well documented. In this paper, we propose a novel method to assess map-reading skills using eye movement metrics and Bayesian structural equation modelling. We recruited 258 participants to complete five map-reading tasks, which included map visualization, topology, navigation, and spatial association. The results indicated that map-reading skills could be reflected in three selected eye movement metrics, namely,the measure of first fixation, the measure of processing, and the measure of search. The model fitted well for all five tasks, and the scores generated by the model reflected the accuracy and efficiency of the participants’ performance. This study might provide a new approach to facilitate the quantitative assessment of map-reading skills based on eye tracking.

To site this paper:

Dong, W.; Jiang, Y.; Zheng, L.; Liu, B.; Meng, L. Assessing Map-Reading Skills Using Eye Tracking and Bayesian Structural Equation Modelling. Sustainability 201810, 3050.

doi:https://doi.org/10.3390/su10093050

Using eye tracking to explore differences in map-based spatial ability between geographers and non-geographers

Abstract: In this article, we use eye-tracking methods to analyze the differences in spatial ability between geographers and non-geographers regarding topographic maps, as reflected in the following three aspects: map-based spatial localization, map-based spatial orientation, and map-based spatial visualization. We recruited 32 students from Beijing Normal University (BNU) and divided them into groups of geographers and non-geographers based on their major. In terms of their spatial localization ability, geographers had shorter response times, higher fixation frequencies, and fewer saccades than non-geographers, and the differences were significant. For their spatial orientation ability, compared to non-geographers, geographers had significantly lower response times, lower fixation counts and fewer saccades as well as significantly higher fixation frequencies. In terms of their spatial visualization ability, geographers’ response times were significantly shorter than those of non-geographers, but there was no significant difference between the two groups in terms of
fixation count, fixation frequency or saccade count. We also found that compared to geographers, non-geographers usually spent more time completing these tasks. The results of this study are helpful in improving the map-based spatial ability of users of topographic maps.

To site this paper:

Dong, W.; Zheng, L.; Liu, B.; Meng, L. Using Eye Tracking to Explore Differences in Map-Based Spatial Ability between Geographers and Non-Geographers. ISPRS Int. J. Geo-Inf. 20187, 337.

doi:https://doi.org/10.3390/ijgi7090337

Using eye tracking to evaluate the usability of flow maps

Abstract: Flow maps allow users to perceive not only the location where interactions take place, but also the direction and volume of events. Previous studies have proposed numerous methods to produce flow maps. However, how to evaluate the usability of flow maps has not been well documented. In this study, we combined eye-tracking and questionnaire methods to evaluate the usability of flow maps through comparisons between (a) straight lines and curves and (b) line thicknesses and color gradients. The results show that curved flows are more effective than straight flows. Maps with curved flows have more correct answers, fixations, and percentages of fixations in areas of interest. Furthermore, we find that the curved flows require longer finish times but exhibit smaller times to first fixation than straight flows. In addition, we find that using color gradients to indicate the flow volume is significantly more effective than the application of different line thicknesses, which is mainly reflected by the presence of more correct answers in the color-gradient group. These empirical studies could help improve the usability of flow maps employed to visualize geo-data.

To cite this paper:

Dong, W *.; Wang, S. *; Chen, Y.; Meng, L. Using Eye Tracking to Evaluate the Usability of Flow Maps. ISPRS Int. J. Geo-Inf. 20187, 281. doi: https://doi.org/10.3390/ijgi7070281

Inferring user tasks in pedestrian navigation from eye movement data in real-world environments

Abstract: Eye movement data convey a wealth of information that can be used to probe human behaviour and cognitive processes. To date, eye tracking studies have mainly focused on laboratory-based evaluations of cartographic interfaces; in contrast, little attention has been paid to eye movement data mining for real-world applications. In this study, we propose using machine-learning methods to infer user tasks from eye movement data in real-world pedestrian navigation scenarios. We conducted a real-world pedestrian navigation experiment in which we recorded eye movement data from 38 participants. We trained and cross-validated a random forest classifier for classifying five common navigation tasks using five types of eye movement features. The results show that the classifier can achieve an overall accuracy of 67%. We found that statistical eye movement features and saccade encoding features are more useful than the other investigated types of features for distinguishing user tasks. We also identified that the choice of classifier, the time window size and the eye movement features considered are all important factors that influence task inference performance. Results of the research open doors to some potential real-world innovative applications, such as navigation systems that can provide task-related information depending on the task a user is performing.

 To cite this paper:
Hua Liao, Weihua Dong*, Haosheng Huang, Georg Gartner & Huiping
Liu (2018): Inferring user tasks in pedestrian navigation from eye movement data in real-world environments. International Journal of Geographical Information Science: 1-25. doi: https://doi.org/10.1080/13658816.2018.1482554

Measuring the influence of map label density on perceived complexity: a user study using eye tracking

Abstract: We combine eye tracking and a questionnaire-based approach to explore the influence of label density on the perceived visual complexity of maps. We design two experiments in which participants are asked to search for the names of point features on maps and to rate the map complexity and legibility for different label densities. Specifically, we conduct a highly controlled experiment in which all the map variables except the label density are held constant (the controlled experiment). Then, we conduct a second experiment following the same protocol but using real maps as visual stimuli (the real-map experiment) to verify if the results of the controlled experiment were applicable to real maps. The results of both experiments indicate a significantly positive correlation between perceived visual complexity and label density and between the response time in visual search tasks and label density. Surprisingly, we observe a significant inverse correlation between the label density and two eye movement parameters (fixation duration and fixation frequency) between the two experiments. We discuss how the variables of real maps might have affected these eye movement parameters and why the results of the two experiments are inconsistent. Our findings suggest that eye tracking parameters are not reliable indicators of map complexity. These empirical results can be helpful to future map design and map complexity investigation.

Cite this paper:

Liao, H., Wang, X., Dong, W., & Meng, L. (2018). Measuring the influence of map label density on perceived complexity: a user study using eye tracking. Cartography and Geographic Information Science, 1-18. DOI: https://doi.org/10.1080/15230406.2018.1434016

Using Eye Tracking to Explore the Guidance and Constancy of Visual Variables in 3D Visualization

Abstract: An understanding of guidance, which means guiding attention, and constancy, meaning that an area can be perceived for what it is despite environmental changes, of the visual variables related to three-dimensional (3D) symbols is essential to ensure rapid and consistent human perception in 3D visualization. Previous studies have focused on the guidance and constancy of visual variables related to two-dimensional (2D) symbols, but these aspects are not well documented for 3D symbols. In this study, we used eye tracking to analyze the visual guidance from shapes, hues and sizes, and the visual constancy that is related to the shape, color saturation and size of 3D symbols in different locations. Thirty-six subjects (24 females and 12 males) participated in the study. The results indicate that hue and shape provide a high level of visual guidance, whereas guidance from size, a variable that predominantly guides attention in 2D visualization, is much more limited in 3D visualization. Additionally, constancy of shape and saturation are perceived with relatively high accuracy, whereas constancy of size is perceived with only low accuracy. These first empirical studies are intended to pave the way for a more comprehensive user understanding of 3D visualization design.

Cite this paper:

Liu, B.; Dong, W.; Meng, L. Using Eye Tracking to Explore the Guidance and Constancy of Visual Variables in 3D Visualization. ISPRS Int. J. Geo-Inf. 20176, 274. doi: 10.3390/ijgi6090274

董卫华团队参加江苏卫视《最强大脑》节目录制

地理科学学部董卫华老师作为特约嘉宾参加江苏卫视《最强大脑》第四季节目录制,该节目已于2017年1月13日在江苏卫视播出,题目为《一眼辨山》。在节目中,选手通过观察三张随机选取的庐山3D实景图,在庐山全貌等高线地形图中绘制相应的观察点和观察方向,选手答案与正确答案相差在四度以内,点位偏差在两百米以内则回答正确,正确两题则挑战成功。为录制该节目,董卫华老师带队进行了为期半年的研究,并亲赴庐山进行实地考察。以下为该节目的视频:

Selection of LiDAR geometric features with adaptive neighborhood size for urban land cover classification

Abstract: LiDAR has been an effective technology for acquiring urban land cover data in recent decades. Previous studies indicate that geometric features have a strong impact on land cover classification. Here, we analyzed an urban LiDAR dataset to explore the optimal feature subset from 25 geometric features incorporating 25 scales under 6 definitions for urban land cover classification. We performed a feature selection strategy to remove irrelevant or redundant features based on the correlation coefficient between features and classification accuracy of each features. The neighborhood scales were divided into small (0.5–1.5 m), medium (1.5–6 m) and large (>6 m) scale. Combining features with lower correlation coefficient and better classification performance would improve classification accuracy. The feature depicting homogeneity or heterogeneity of points would be calculated at a small scale, and the features to smooth points at a medium scale and the features of height different at large scale. As to the neighborhood definition, cuboid and cylinder were recommended. This study can guide the selection of optimal geometric features with adaptive neighborhood scale for urban land cover classification.

Cite this paper: Dong, W., Lan, J., Liang, S., Yao, W. and Zhan, Z. 2017. Selection of LiDAR geometric features with adaptive neighborhood size for urban land cover classification. International Journal of Applied Earth Observation and Geoinformation, 60, 99-110. DOI: 10.1016/j.jag.2017.04.003

Global and regional changes in exposure to extreme heat and the relative contributions of climate and population change

Abstract: The frequency and intensity of extreme heat wave events have increased in the past several decades and are likely to continue to increase in the future under the influence of human-induced climate change. Exposure refers to people, property, systems, or other elements present in hazard zones that are thereby subject to potential losses. Exposure to extreme heat and changes therein are not just determined by climate changes but also population changes. Here we analyze output for three scenarios of greenhouse gas emissions and socio-economic growth to estimate future exposure change taking account of both climate and population factors. We find that for the higher emission scenario (RCP8.5-SSP3), the global exposure increases nearly 30-fold by 2100. The average exposure for Africa is over 118 times greater than it has been historically, while the exposure for Europe increases by only a factor of four. Importantly, in the absence of climate change, exposure is reduced by 75–95% globally and across all geographic regions, as compared with exposure under the high emission scenario. Under lower emission scenarios RCP4.5-SSP2 and RCP2.6-SSP1, the global exposure is reduced by 65% and 85% respectively, highlighting the efficacy of mitigation efforts in reducing exposure to extreme heat.

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An Exploratory Study Investigating Gender Effects on Using 3D Maps for Spatial Orientation in Wayfinding

Abstract: 3D representations in applications that provide self-localization and orientation in wayfinding have become increasingly popular in recent years because of technical advances in the field. However, human factors have been largely ignored while designing 3D representations in support of pedestrian navigation. This exploratory study aims to explore gender effects on using 3D maps for spatial orientation. We designed a 3D map that combines salient 3D landmarks and 2D layouts, and evaluated gender differences in their performance during direction-pointing tasks by administrating an eye tracking experiment. The results indicate there was no significant overall gender difference on performance and visual attention. However, we observed that males using the 3D map paid more attention to landmarks in the environment and performed better than when using the conventional 2D map, whereas female performance did not show any significant difference between the two types of map usage. We also observed contrary gender differences in visual attention on landmarks between the 3D and 2D maps. While males fixated longer on landmarks than females when using the 3D map, females paid more visual attention to landmarks than males when using the 2D map. In addition, verbal protocols showed that males had more confidence while make decisions. These empirical results can be helpful in the design of map-based wayfinding enhancement tools.

Cite this paper: Liao H, Dong W. An Exploratory Study Investigating Gender Effects on Using 3D Maps for Spatial Orientation in Wayfinding. ISPRS International Journal of Geo-Information. 2017; 6(3):60. DOI: http://dx.doi.org/10.3390/ijgi6030060