Are People Ready for Raster Digital Soil Survey Data?

1. Are People Ready for Raster Digital Soil Survey Data? Janis Boettinger Amy Rohman Utah State University Suzann Kienast-Brown USDA-NRCS, Utah

2. Rationale • Publicly available soil survey maps • Vector Polygon • Digital • USA - True • World - True • Review of Global Digital Soil Spatial Data • James Thompson, West Virginia University, in Grunwald et al. (accepted) SSSAJ

3. Rationale • If soil survey maps were available in alternate forms… • Raster (pixel) digital …what would people’s perceptions & preferences be? Are People Ready for Raster Digital Data?

4. Hypotheses • People ARE ready for raster digital data • Perceptions & preferences of map influenced by factors • Age • Area of work/study • Prior experience with soil survey maps

5. Methods & Materials • Developed interview questionnaire • Demographic information • Age groups • Education • Areas of Work/Study • Assessed experience with soil survey • Establish baseline of experience • Custom Soil Survey Report of Part of Cache Valley, Utah • 3 Maps: UT602, Bear River Migratory Bird Refuge • 3 Qualities rated High, Medium, or Low

13. All interviewees shown a Digital Orthophoto Quad of the Survey Area before 3 maps.

14. Map Qualities • Visual appeal • Conveying information about the spatial distribution of soils • Determining the soil type(s) mapped at a specific location • High • Medium • Low

15. Map A: Black & White DOQ with Polygons

16. Map B: Colored Pixels over DOQ

17. Map C: Colored Pixels Only

18. Methods & Materials • 65 Interviews – conducted in person, one-on-one • Suzann Kienast-Brown • NRCS Soil Scientist & RS-GIS Specialist, Utah • About 15 interviews • NRCS, USFS, Arts community in northern Utah • Amy Rohman • Undergraduate Research Assistant • Natural Resources major • Summer and fall following freshman year • About 50 interviews • Diverse sample of USU students & faculty, family, friends • Opportunity to educate people about soil survey

19. Methods & Materials • Results summarized • Histograms, descriptive statistics • Categories High, Medium, Low • Ranked 1, 2, 3, respectively • Statistical analysis • Kolmogorov-Smirnov Test (K-S Test) • Non-parametric • No assumptions regarding normality • Compares cumulative distribution functions of two samples • D-statistic = Maximum distance between cumulative distribution functions • Significantly different at P=0.05

20. Results – All (N=65)

21. Visual Appearance D = 0.446, P<0.001*

22. D Ai vs. Bi

23. Visual Appearance D = 0.446, P<0.001*

24. Bi vs. Ci

25. Visual Appearance D = 0.431, P<0.001*

26. Visual Appearance D = 0.446, P<0.001 D = 0.431, P<0.001 Color pixel maps (B and C) rated higher for visual appearance than B&W polygon map. No other statistically significant differences

27. Age: 18-49 vs. 50-60+

28. Age: 18-49 vs 50-60+ No significant differences (at P=0.05) between groups for all 3 map qualities

29. Work/Study: Ag/NR vs. Other

30. Work/Study: Ag/NR vs. Other No significant differences (at P=0.05) between groups for all 3 map qualities

31. Prior SS Use vs. No Prior SS Use

32. Prior SS Use vs. No Prior SS Use D = 0.349, P=0.048*; Polygon lines over air photo: Conveying info on soil spatial distribution

33. Prior SS Use vs. No Prior SS Use D = 0.349, P=0.048*; Color pixel map over air photo: Visual Appearance

34. Prior SS Use vs. No Prior SS Use

35. Prior SS Use vs. No Prior SS Use Prior SS Use: No significant differences (at P=0.05) between maps for all qualities

36. Prior SS Use vs. No Prior SS Use Prior SS Use: No significant differences (at P=0.05) between maps for all qualities D=0.580, P<0.001

37. Prior SS Use vs. No Prior SS Use Prior SS Use: No significant differences (at P=0.05) between maps for all qualities D=0.568, P<0.001 D=0.500, P<0.001

38. Summary • Overall (N=65) • Color pixel maps (both) rated higher for visual appearance that B&W polygon maps • No significant differences in rating B&W poygon vs. color pixel maps for • Conveying info on spatial distribution of soils • Determining soil type(s) mapped for specific location

39. Summary • B&W polygon map rated higher: Conveying information on spatial distribution of soils • Prior soil survey experience (N=21) • Color pixel over air photo base map rated higher: Visual appearance • No prior soil survey experience (N=44)

40. Summary • Prior soil survey use • No significant differences in ratings of map qualities for all maps • No prior soil survey use • Color pixel maps (both) rated higher for visual appeal

41. Conclusions • Prior soil survey use influenced ratings • Visual appeal of B&W polygon vs. color pixel • B&W polygon for conveying information on spatial distribution of soils

42. Conclusions • Prior soil survey use influenced ratings • Visual appeal of B&W polygon vs. color pixel • B&W polygon for conveying information on spatial distribution of soils • No differences between maps for gaining information, regardless of prior soil survey use • Spatial distribution of soils • Determining soil (s) mapped at specific location

43. Conclusions People ARE ready for raster digital soil data!