Cognitive Issues in Geographic Information Visualization

Perception and Thematic Map Symbol Design I

3708.1 - An Evaluation of Pictorial Symbols for Tourist Maps based on the Perceptual Laws of Gestalt Theory

Monday, July 3
4:10 PM - 4:30 PM
Location: Maryland C

INTRODUCTION: This paper describes some results of a research work in which the main goal is to understand how the visual perception of tourist maps built with pictorial symbols can stimulate spatial knowledge acquisition when the users accomplish map tasks related to symbol detection, discrimination, and recognition. We analyzed the results by some of the perceptual laws of Gestalt Theory: figure-ground, Prägnanz, perceptual grouping by proximity and similarity, and closure. We established the research hypothesis as that the pictorial symbols must have a semantic relation with the represented object, a mimetic level that minimizes the interpretation ambiguities, and a visual simplicity and balance. Besides, when a pictorial symbol is near to other symbols, it can be difficult to discriminate it since its shape is an associative visual variable, and therefore, it stimulates a group perception. METHOD: We verified the hypothesis from the analysis of the results that we obtained with an experiment we have designed in three steps. First, we constructed the pictorial symbols and the tourist map. Second, we prepared a questionnaire from which we could know the participants’ characteristics that must be related to the map use results. And in the end, we organized another questionnaire based on cognitive tasks of a basic level: detection, discrimination, and recognition. We created a map of the historical downtown of Curitiba city, Brazil. Therefore, the symbols depicted real tourist features which allowed us to develop an ecological validation of the results. To evaluate the influence of the figure-ground relationship on the symbol perception, we designed two maps with two sets of symbols. We drew the symbols in both sets with the same shape and size, and they were all black on a white background. However, we colored one set of symbols in black (filled up symbols), and we left the other set white inside (just the contour of the symbol's shape). We designed two tests with the same questions but with both sets of symbols for two different groups of participants, which helped us to verify the influence of the figure-ground relationship in the detection and recognition of the symbol. In the second step of tests, we prepared a questionnaire to know the participant's profile and, especially, their background on making maps and experiences on using tourist maps. It is important to mention that the participants were volunteers. The third step was an open questionnaire prepared with some map user tasks. CONCLUSIONS: There were 176 participants, of which 97 were males and 79 females. Their ages vary from 18 to 40 years old. From the analysis of the results, we can affirm that the first sight symbols were those located in the center of the map, and the ones in the larger group of symbols or close to it, which confirms the Gestalt law of the perceptual grouping by proximity. For the map with colored symbols, the darkest ones were easier seen than the lighter ones. Verifying the first and the last sight symbols, we could also conclude that the Gestalt law of Prägnanz depends on the figure-ground relation and the picture convexity. The least recognized symbols in both maps were the ones the least seen, which shows us that the mimetic level of the image influences the symbol recognition. However, the symbol recognition also depends on the cultural impact and semantic relationship with the object it represents. Furthermore, the results showed us that the influence of Prägnanz law of the colored symbols is as much strong as their location on the map. For countered symbols, the perceptual grouping has primacy over Prägnanz in the detection and discrimination of the symbols.

Claudia R. Sluter

Professor
Federal University of Parana - UFPR

Bachelor at Cartographic Engineering from Federal University of Paraná - UFPR (1986). Master at Geodetic Science from Federal University of Paraná - UFPR (1993). Doctorate at Computer Science from National Institute for Space Research - INPE (2000). Sandwich doctorate at Geography Department of the University of Kansas (1998). I am currently full professor at Federal University of Paraná - UFPR. I teach and research on the following subjects: geovisualization, thematic mapping, cartographic generalization, topographic mapping, interactive map design, and GIS.

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Amy L. Griffin

Senior Lecturer
UNSW Canberra

Dr. Amy Griffin is a Senior Lecturer in Geography at UNSW Canberra. She is currently a co-chair of the ICA Commission on Cognitive Issues in Geographic Information Visualization (CogVIS). Her research interests include investigating cognitive and perceptual processes involved in using maps, information visualizations and other forms of geospatial information.

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