Visualizing Ten Years of Quantitative Color Schemes

Travis White
University of Kansas
#nacis2015

Transcript

2. (color that represents quantitative data) Qc = Quantitative color schemes
3. Existing research & resources indicate how Qc should be used…
4. Existing research & resources indicate how Qc should be used… How are mapmakers using Qc?
5. Qc Map Review & Evaluation Key parameters ∙2004-2013 ∙geographic journals from multiple fields ∙no cartographic articles
6. Qc Map Review & Evaluation Key parameters ∙2004-2013 ∙geographic journals from multiple fields ∙no cartographic articles ∙at least one map selected per article ∙univariate maps only ∙no elevation maps
7. Qc Map Review & Evaluation Key parameters ∙2004-2013 ∙geographic journals from multiple fields ∙no cartographic articles ∙at least one map selected per article ∙univariate maps only ∙no elevation maps 440 Qc maps from 315 articles
8. Human Human & Physical Physical
9. 100% 80% 60% 40% 20% 0% 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Qualitative color scheme rates 11% 29% 42% 71%
10. Question 1 Which Qc schemes were used? How appropriately? By whom?
11. Question 1 Which Qc schemes were used? How appropriately? By whom? Question 2 Which colors were used? How appropriately? By whom?
12. Question 1 Which Qc schemes were used? How appropriately? By whom? Question 2 Which colors were used? How appropriately? By whom?
13. 2 Qc mapper personas:
14. Persona 1 ∙maps human data ∙works w/ unipolar data ∙prefers choropleth (enum. units) ∙uses fewer data classes 2 Qc mapper personas:
15. Persona 1 ∙maps human data ∙works w/ unipolar data ∙prefers choropleth (enum. units) ∙uses fewer data classes 2 Qc mapper personas: Persona 2 ∙maps physical data ∙works equally between polarities ∙prefers surface data ∙uses more data classes
16. Useful color assessment requires accurate color identification, but… consistent accurate sampling not possible with unclassed schemes: Cloetingh 2007 , Koch 2009, Fischer 2001, Salvati 2013
17. Gimpel 2004, Combes 2005, Wahl 2012, Holand 2013 However… consistent, accurate sampling is possible with classed Qc
18. Classed Qc sampling process Photoshop CC 2015 sRGB IEC61966-2.1 color profile RGB color image mode example: Escutia 2005 Confirm the color profile, copy legend to a new layer Edit out pixel noise
19. Classed Qc sampling process Photoshop CC 2015 sRGB IEC61966-2.1 color profile RGB color image mode example: Escutia 2005 Average the edited color pixel values Point sample the averaged color values [eyedropper]
20. DISCLAIMER Sampling & evaluations based on digital versions of maps, not original map files. Qc scheme appearances are inconsistent across display devices.
21. Sequential Diverging non-spectral Spectral Traffic Other Qc Overview 5 primary schemes
22. Sequential Red/Orange/Yellow ∙n = 99 (31% of all Qc maps) ∙primary scheme for choropleths ∙preferred scheme for human data
23. Sequential Green/Blue/Purple ∙n = 99 (31% of all Qc maps) ∙primary scheme for choropleths ∙preferred scheme for human data
24. Sequential Yellow/Orange/Brown ∙n = 99 (31% of all Qc maps) ∙primary scheme for choropleths ∙preferred scheme for human data
25. Sequential Examples
26. Sequential Examples
27. Sequential Examples
28. Diverging non-spectral (critical class) ∙n = 86 (27% of all Qc maps) ∙common on both choro & surface maps ∙more frequently used for physical data
29. Diverging non-spectral (critical break) ∙n = 86 (27% of all Qc maps) ∙common on both choro & surface maps ∙more frequently used for physical data
30. Diverging non-spectral Examples
31. Diverging non-spectral Examples
32. Spectral (non-diverging) ∙n = 76 (24% of all Qc maps) ∙overwhelmingly used on surface maps ∙overwhelmingly used for physical data
33. Spectral (diverging) ∙n = 76 (24% of all Qc maps) ∙overwhelmingly used on surface maps ∙overwhelmingly used for physical data
34. Spectral Example
35. Spectral Example
36. Spectral Example
37. Traffic (diverging & non-diverging) ∙n = 26 (8% of all Qc maps) ∙more common on surface maps ∙used for half of all human + physical data
38. Traffic Example
39. Other (hypso, thermal, undefined…) ∙n = 35 (11% of all Qc maps) ∙no noteworthy patterns
40. Other Example
41. Other Example
42. Accentuating the positive ∙Sequential & Diverging schemes used appropriately ∙Qc schemes rarely lost in visual hierarchy ∙Color deficiency not too problematic (ignoring Spectral & Traffic schemes)
43. Accentuating the negative ∙Too many classes! ∙Poor color grading (cannot distinguish colors within a scheme) ∙Poor matching btwn data type & Qc (e.g., unipolar data + diverging scheme) ∙Illogical sequencing of colors ∙Image quality matters!
44. Recommendations ∙Educate & Inform! mappers need instruction and guidance ∙Improve graphics publication guidelines ∙Improve or limit software/package offerings ∙A Brewer for non-choro mapping (?)
45. “GOOD ENOUGH” is not good enough!
46. Appropriate Qc usage ≠ GOOD DESIGN
47. Thank You! Expanded slides & RGB profiles available at: References Bordi, I. and A. Sutera. 2004. Drought variability and its climatic implications, Global and Planetary Change 40, 115–127 . Brewer, Cynthia A., 2013. http://www.colorbrewer2.org, accessed October 4, 2015 Gillespie, T, Foody, G., Saatchi, S. 2008. Measuring and modelling biodiversity from space, Progress in Physical Geography 32, 203. Groisman, P . Y. 2007 . Potential forest fire danger over Northern Eurasia: Changes during the 20th century, Global and Planetary Change, 56, 371–386. Kaplan, D. and G. Sommers. 2009. An Analysis of the Relationship Between Housing Foreclosures, Lending Practices, and Neighborhood Ecology: Evidence from a Distressed County, The Professional Geographer, 61:1, 101-120. Lewis, L. 2010. Biogeography and Genetic Diversity of Pearl Millet (Pennisetum glaucum) from Sahelian Africa , The Professional Geographer, 62:3, 377-394. Lombard, A. 2005. Contribution of thermal expansion to present-day sea-level change revisited, Global and Planetary Change 47 , 1–16. Maliszewski, P . and M. Horner. 2010. A Spatial Modeling Framework for Siting Critical Supply Infrastructures , The Professional Geographer, 62:3, 426-441. Morehouse, B and S. O’Brien. 2008. Facilitating Public Involvement in Strategic Planning for Wildland Fire Management , The Professional Geographer, 60:4, 495-507 . Setton, E. 2010. Gender Differences in Chronic Exposure to Traffic-Related Air Pollution—A Simulation Study of Working Females and Males, The Professional Geographer, 62:1, 66- 83. Taus, A. 2013. Conversion to Organic Farming in the Continental United States: A Geographically Weighted Regression Analysis, The Professional Geographer, 65:1, 87-102. Wen, T., Lin, M., Fang, C. 2012. Population Movement and Vector-Borne Disease Transmission: Differentiating Spatial–Temporal Diffusion Patterns of Commuting and Noncommuting Dengue Cases, Annals of the Association of American Geographers, 102:5, 1026-1037 .