Evaluating the Effectiveness of Illuminated and Shadowed Contour Lines

James Eynard
Bernhard Jenny
Cartography and Geovisualization Group
Oregon State University
#nacis2015

Transcript

1. Evaluating the Effectiveness of Illuminated and Shadowed Contour Lines James Eynard and Bernhard Jenny Cartography and Geovisualization Group Oregon State University NACIS | 2015 | Minneapolis, MN
2. Conventional Illuminated Shadowed Types of Contour Lines Elevation of Mt. Hood, Oregon
3. History Contouring Software User Study Evaluating the Effectiveness of Illuminated and Shadowed Contour Lines
4. 1845 Michaelis, E.H., 1845. Passage du Splügen et de la Via Mala (map, 1:125 000) Inset in: Über die Darstellung des Hochgebirges in topographischen Karten. Berlin: Schropp.
5. Swiss Alpine Club, 1865. Karte der Gebirgsgruppe zwischen Lukmanier & La Greina (map 1:50 000, contour interval 30 meters, map by Rudolf Leuzinger) 1865
6. Randegger, J., 188-. Wandkarte des Kantons Thurgau (map, 1:50 000). Winterthur: Topographische Anstalt von Wurster, Randegger & Cie. 1880s
7. Köpcke, C., 1885. Ueber Reliefs und Relief-Photogramme. Der Civilingenieur, 31, 1–2. 1885 – Photograph of Cardboard Cutouts
8. Pauliny, J., 1895. Mémoire über eine neue Situationspläne- und Landkarten-Darstellungsmethode. Streffleurs Österreichische Militärische Zeitschrift, 4 (1), 66–87. 1891
9. Tanaka, K., 1950. The relief contour method of representing topography on maps. Geographical Review, 40 (3), 444–456. 1950 – Tanaka Contours
10. Gilman, C.R., 1973. Photomechanical experiments in automated cartography. Journal of Research of the U.S. Geological Survey, 1 (2), 223–228. 1973
11. Yoeli, P. 1983. Shadowed Contours with Computer and Plotter 1983 – Computer-based techniques
12. Eyton, J. R. 1984. Raster contouring. Geo-Processing 2: 221-42. 1984 – Computer-based techniques
13. Kennelly, P. and Kimerling, A. J. (2001). ‘Modifications of Tanaka’s illuminated contour method’, Cartography and Geographic Information Science, 28, pp. 111–123. 2001 – Modified Tanaka Contour Lines
14. Imhof, E. (1965). Kartographische Geländedarstellung. Walter de Gruyter. Imhof, E. (2007). Cartographic relief presentation. ESRI, Inc..
16. Manual and Semi-automated Techniques •  Time consuming, inconsistent results •  Calligraphy-style pens •  Digital –  Adobe Illustrator, Photoshop –  Scripts
17. Contouring Software
18. Generalization of Contour Lines
19. Adjust Illumination Angle NW SE
20. Adjust Contour Interval 100 m 300 m
21. Adjust Line Thickness
22. Adjust Line Thickness (for illuminated and shadowed side)
23. Adjust Transition Angle 90º 120º
24. Despeckle
25. Minimum Distance Between Contour Lines
26. Shadowed Contour Lines
28. User Study
29. Previous User Studies Several studies on contour map interpretation, but… a lack of studies on illuminated contour lines “no empirical evaluation of the method exists nor any empirically derived guidelines on appropriate maximum widths for the variable contours” (MacEachren 2004, p. 147) Wheate, R.D., 1979. Commensurability versus imageability: a re-assessment of the role played by shaded relief on topographic maps. Thesis (Master’s). Queen’s University. Morita, T., 2001. Visual characteristics of Tanaka’s relief representation method through observation of eye movement. In: International Cartographic Commission on Theoretical Cartography.
30. User Study Hypothesis Certain features of topography can be interpreted more quickly and accurately by map-readers with illuminated and shadowed contours maps than with conventional contour maps.
31. User Study •  Conventional contour lines •  Shadowed contour lines •  Illuminated contour lines •  Shaded relief Within Groups Mechanical Turk -> Qualtrics, 397 participants
32. User Study Sections Tutorial Relative Height Questions 10 second time limit Contour labels 10 x 4 map types, randomized Maximum Height Questions 20 second time limit No contour labels 12 locations, randomized map types 3-D representation and demographics
33. Relative Height Question Example
34. Maximum Height Question Example
35. User Study Results •  Relative Height Question •  Accuracy •  Timing •  Maximum Height Question •  Accuracy •  Timing •  3-D representation and demographics
36. User Study Results Relative Height Question – Accuracy Map$type$pairs$ χ2$ Sig$ ! ! ! Illuminated!–!shadowed! 4.6750! yes! Illuminated!–!conventional! 10.0831! yes! Illuminated!–!shaded!relief! 15.2345! yes! Shadowed!–!conventional! 1.0151! no! Shadowed!–!shaded!relief! 3.0127! no! Shaded!relief!–!conventional! 0.5214! no! ! ! ! ! McNemar’s test results, χ2-crit = 3.8415 89.4%& 84.8%& 81.5%& 83.1%& 50%& 60%& 70%& 80%& 90%& 100%& Illuminated& Shadowed& Shaded& Relief& Conven?onal& Percent'Correct'
37. User Study Results Relative Height Question – Timing Map$type$ Mean$timing$ (seconds)$ Std$dev$ timing$ ! ! ! Illuminated! 3.0! 1.3! Shadowed! 3.4! 1.5! Conventional! 3.6! 1.6! Shaded!relief! 2.5! 1.1! ! ! ! ! Wilcoxon signed-ranks test – Significance for all map pairs at p < 0.01 Map$type$pairs$ Effect$r$ Effect$size$sig$ ! ! ! Illuminated!–!shadowed! 0.23! low! Illuminated!–!conventional! 0.30! med! Illuminated!–!shaded!relief! 0.34! med! Shadowed!–!conventional! 0.12! low! Shadowed!–!shaded!relief! 0.46! med! Shaded!relief!–!conventional! 0.49! med! ! ! ! !
38. User Study Results Maximum Height Question – Accuracy Map$type$ Mean$accuracy$ Std$dev$ ! ! ! Illuminated,!unlabeled! 79.5%! 15.7%! Shadowed,!unlabeled! 75.3%! 20.8%! Conventional,!labeled! 79.4%! 18.1%! Shaded!relief! 69.6%! 19.8%! ! ! ! ! Wilcoxon signed-ranks test and Cohen’s r effect size results Map$type$pairs$ P,value$ Sig$ Effect$r$ Effect$size$sig$ ! ! ! ! ! Illuminated!–!shadowed! <!0.01! yes! 0.01! no! Illuminated!–!conventional! 0.741! no! X! X! Illuminated!–!relief! <!0.01! yes! 0.38! med! Shadowed!–!conventional! <!0.01! yes! 0.13! low! Shadowed!–!shaded!relief! <!0.01! yes! 0.27! low! Shaded!relief!–!conventional! <!0.01! yes! 0.39! med! ! ! ! ! ! !
39. User Study Results Maximum Height Question – Timing Map$type$ Mean$timing$ (seconds)$ Std$dev$ timing$ ! ! ! Illuminated,!unlabeled! 6.2! 3.6! Shadowed,!unlabeled! 6.1! 3.7! Conventional,!labeled! 6.3! 3.3! Shaded!relief! 7.9! 3.8! ! ! ! !
40. For each map type, participants were asked if they agree with the following statement: This map shows variations in elevation well and produces an appearance of the third dimension. 43.1%& 25.3%& 8.9%& 7.1%& 43.1%& 57.5%& 45.7%& 30.8%& 5.6%& 8.2%& 20.2%& 19.3%& 6.6%& 7.4%& 22.4%& 35.4%& 0%& 10%& 20%& 30%& 40%& 50%& 60%& 70%& 80%& 90%& 100%& Relief& Illuminated& Shadowed& Conven@onal& Strongly&Agree& Agree& Neither& Disagree& Strongly&Disagree&
41. User Study Results Demographics No significance •  Age •  Gender •  Education level •  Self-evaluated topographic map reading ability
42. Conclusions Illuminated contour lines – quicker and more accurate Shadowed contour lines – quicker and more accurate to a lesser extent for some map reading tasks Mechanical Turk – unexpected results
43. Limitations and Potential Use •  Neutral background •  Bathymetry maps •  Other statistical surfaces •  Variations and future user studies •  Subtle color and line width changes •  More detailed maps •  Various scales
45. Created by Sam Hooper and published in the Atlas of Polar Regions
46. Created by Mathias Wigum and Bernhard Jenny and published in the Atlas of Polar Regions
47. Acknowledgements Oregon State University Tom Patterson Dr. Richard Oliver AAG Cartography Specialty Group Bojan Šavrič, Charles Preppernau, Brooke Marston, and Lawrence Sim
48. Pyramid Shader – free and open source software for creating illuminated and shadowed contour lines •  Shaded relief •  Plan oblique relief •  Hypsometric colors •  Local hypsometric colors •  Terrain generalization •  Bivariate colors •  Slope •  Aspect
50. Pyramid Shader www.terraincartography.com/PyramidShader Questions?