Legend Layouts for Thematic Maps: A Case Study Integrating Usability Metrics with the Thinking Aloud Method

Abstract The legend is a critical tool in reading and interpreting a thematic map. The goal of the study reported here is to understand how the legend works as a map is read. The methodology combined usability performance metrics with the thinking aloud method. Subjects were asked to perform two sets of tasks using two thematic maps with different legend layouts. While latency and accuracy of answers for the first set of tasks did not differ significantly between users of the different layouts, users clearly preferred legends that were simple or familiar. The thinking aloud protocols from the second part of the study revealed different patterns of legend comprehension for each legend design. In addition, the study identified four problem-solving strategies that were adopted by the subjects. Finally, some principles for designing legends were developed from the results of the study.

[1]  Jeremy W. Crampton,et al.  A Cognitive Analysis of Wayfinding Expertise , 1992 .

[2]  W. Hays.  Semiology of Graphics: Diagrams Networks Maps. , 1985 .

[3]  Mark Monmonier,et al.  Graphic communication and design in contemporary cartography , 1983 .

[4]  John W. Creswell,et al.  Research Design: Qualitative, Quantitative, and Mixed Methods Approaches , 2010 .

[5]  Gennady Andrienko,et al.  Novel Method to Measure Inference Affordance in Static Small-Multiple Map Displays Representing Dynamic Processes , 2008 .

[6]  Linda W. Pickle,et al.  A Cognitive Subtask Model of Statistical Map Reading , 1996 .

[7]  J. Sandberg,et al.  The think aloud method , 1994 .

[8]  O. Svenson.  Differentiation and consolidation theory of human decision making: A frame of reference for the study of pre- and post-decision processes , 1992 .

[9]  Cathy Moulder.  How Maps Work , 2009 .

[10]  Ola Svenson,et al.  Emerging Perspectives on Judgment and Decision Research: Values, Affect, and Processes in Human Decision Making: A Differentiation and Consolidation Theory Perspective , 2003 .

[11]  Arzu Çöltekin,et al.  Evaluating the Effectiveness of Interactive Map Interface Designs: A Case Study Integrating Usability Metrics with Eye-Movement Analysis , 2009 .

[12]  Daniel R. Montello,et al.  Cognitive Map-Design Research in the Twentieth Century: Theoretical and Empirical Approaches , 2002 .

[13]  Oliver Schreer,et al.  ELAN as Flexible Annotation Framework for Sound and Image Processing Detectors , 2010, LREC.

[14]  Alan A. DeLucia,et al.  Natural Legend Design for Thematic Maps , 1982 .

[15]  Stephen Lavin,et al.  Legend Designs for Unclassed, Bivariate, Choropleth Maps , 1989 .

[16]  Alan M. MacEachren,et al.  Cartographic animation and legends for temporal maps : exporation and or interaction , 1997 .

[17]  Doris R. Pridemore,et al.  Cartographic experience and thinking aloud about thematic maps , 1992 .

[18]  Jason Dykes,et al.  vizLegends : Re-Imagining Map Legends with Visualization , 2010 .

[19]  K. A. Ericsson,et al.  Protocol Analysis: Verbal Reports as Data , 1984 .

[20]  M. Chi.  Quantifying Qualitative Analyses of Verbal Data: A Practical Guide , 1997 .

[21]  Clarke Wilson,et al.  ClustalG: Software for analysis of activities and sequential events , 1999 .

[22]  Clarke Wilson,et al.  Activity patterns in space and time: calculating representative Hagerstrand trajectories , 2008 .

[23]  Jason Dykes,et al.  Rethinking Map Legends with Visualization , 2010, IEEE Transactions on Visualization and Computer Graphics.

[24]  D. Wood.  How Maps Work , 1992 .

[25]  Terry A. Slocum.  Thematic Cartography and Geographic Visualization , 2004 .

[26]  Carleton W. Cox.  Anchor Effects and the Estimation of Graduated Circles and Squares , 1976 .

[27]  C.P.J.M. van Elzakker,et al.  The use of maps in the exploration of geographic data , 2004 .

[28]  Mario A. Gomarasca,et al.  Elements of Cartography , 2009 .