Menno-Jan Kraak - The time wave


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Menno-Jan Kraak - The time wave

  1. 1. The usability of alternative temporal visual representations: The time-wave in a geovisual analytics environment The usability of alternative temporal visual representations: the time-wave in a geovisual analytics environment • Background • Time space, time graphs and coordinated multiple views • Time wave Menno-Jan Kraak & Xia Li • Usability aspects of the approach • Conclusions Our operational research context Visual problem solving from time perspective • What is the most suitable graphic representation? ‣ design ‣ geocomputational support ‣ reasoning based on graphics PROBLEM user tasks Task Working environment (Geospatial) Data Graphic representation Function tools data framework • What is the best working environment? ‣ functionality /visualization strategy ‣ web-based ‣ multi resolution data integration Data perspective on time user tasks Time perspectives time questions temporal data Task temporal user tasks Working environmenttemporal (Geospatial) Data Graphic representation visualization framework • Does it work? ‣ efficiency ‣ effectiveness ‣ satisfaction User tasks PROBLEM data framework visualization Function tools time space visualization framework Visualization Some basics attribute space DATA USER TASK • Linear and cyclic • When • Time line • Instant and interval • How long • Time wheel • Absolute and relative • How often • Diagrams • Continuous and discrete • What order • Maps • ..... what? VISUALIZATION • ..... t • ..... when? where? location space t time space
  2. 2. Spaces and graphics Time graphs: visualizations in time space • ‘visual inference’ in time space that results in action in location and/or attribute space • time line / time wheel Location space Attribute space MAP DIAGRAM • time wave time wheel offset (start cyclic) wavelength = time unit time wave amplitude (radius wheel) time line TIME GRAPH Time space Time wave At work with the time wave TIME SPACE year year how long? ? when? how often? if? beiijng xian shanghai annual sighting of plant A what order? year C B ATTRIBUTE July 24 July 25 July 26 ID 54419 ID 54499 July 27 July 28 temperature magnitude earthquake 1-3 4-6 7-9 Geovisual analytics environments Geovisual analytics environment and visualization strategies SPACE
  3. 3. Usability testing Evaluation: user requirements objective methodology nature of user’s temporal data kind of questions asked • User requirements questionnaire • Time wave versus time line (linear) and time wheel (cyclic) results samples • ‘Performance’ of time wave linear cyclic 2005 both relative absolute monday three 9 - 11 2006 tuesday hours am .... .... .... 25% • Time wave, coordinated multiple view environment, and geovisual analytics 48% 38% 27% from linear cyclic both Evaluation: time graphs 19% 43% relative absolute both Evaluation: time wave objective objective methodology compare time wave with time line and time wheel observe execution task, interview results sample correctness samples 100,0 Did it rain on the 2nd Feb 2001 in Haikou? 50,0 right wrong cannot How often did it rain in 2nd wk of Feb ‘01 in Xi’an? eye movement, think aloud results How often times does event A happened in the third week of January 75,0 Did it rain on the second Tuesday in Feb in Haikou? methodology ‘performance’ of the time wave 25,0 0 time line time wheel time wave response time 160,0 120,0 80,0 ! 40,0 ! ! 0 ! time line time wheel time wave Evaluation: time wave in its environment objective Time wave and Space-Time-Cube methodology what is the user behaviour in the coordinated multiple view environment eye movement think aloud samples results what > where questions when > what questions where > when questions ... ! !
  4. 4. Conclusions References • • Time space helps to organize a user’s temporal questions • The time wave is, depending on the nature of the temporal questions a good alternative for the traditional time graphs like the line and wheel • Basics of time-wave: Li, X. and M. J. Kraak (2008). "The Time Wave - A new method to visually explore geo-data in time space." The Cartographic Journal 45(3). • Integration of the findings in current theory are being elaborated Li, X. and M. J. Kraak (publication in preparation).