UNIT 49 - VISUALIZATION OF SPATIAL DATA

UNIT 49 - VISUALIZATION OF SPATIAL DATA

Compiled with assistance from Matt McGranaghan, University of Hawaii

  • A. INTRODUCTION
  • B. CARTOGRAPHIC BACKGROUND
  • C. GRAPHIC VARIABLES
  • D. PERCEPTUAL AND COGNITIVE LIMITATIONS
  • E. GRAPHIC LIMITS
  • F. REPRESENTING UNCERTAINTY
  • G. TEMPORAL DEPENDENCE
  • H. SHOWING A THIRD DIMENSION
  • REFERENCES
  • EXAM AND DISCUSSION QUESTIONS
  • NOTES

    UNIT 49 - VISUALIZATION OF SPATIAL DATA

    Compiled with assistance from Matt McGranaghan, University of Hawaii

    A. INTRODUCTION

    Maps

    Computer-generated displays

    B. CARTOGRAPHIC BACKGROUND

    Visualization

    What is the image supposed to show?

    To whom?

    Ideal display

    C. GRAPHIC VARIABLES

    1. Location

    2. Value

    3. Hue

    4. Size

    5. Shape

    6. Spacing

    7. Orientation

    D. PERCEPTUAL AND COGNITIVE LIMITATIONS

    E. GRAPHIC LIMITS

    F. REPRESENTING UNCERTAINTY

    Explicit uncertainty codes

    Graphic ambiguity

    Examples

    G. TEMPORAL DEPENDENCE

    Basic strategies

    H. SHOWING A THIRD DIMENSION

    Contours

    Hypsometric mapping

    Simulating oblique views of surface

    REFERENCES

    Standard texts on map design:

    Cuff, D.J., and Mattson, M.T., 198. Thematic Maps: Their design and Production, Methuen, New York.

    Dent, B.D., 1985. Principles of Thematic Map Design. Addison- Wesley, New York.

    Tufte, E.R., 1983. The Visual Display of Quantitative Information. Graphics Press, Cheshire, CT. A fascinating discussion including many cartographic examples.

    Texts on computer graphics:

    Durrett, H.J. ed., 1987. Color and the Computer. Academic Press, New York.

    Foley, J.D., and Van Dam, A., 1982. Fundamentals of Interactive Computer Graphics. Addison-Wesley, New York.

    Myers, R.E., 1982. Microcomputer Graphics. Addison-Wesley, Reading, MA.

    Design for digital maps:

    Monmonier, M., 1982. Computer-Assisted Cartography: Principles and Prospects. Prentice-Hall, Englewood Cliffs NJ.

    Techniques for displaying topography:

    Kennie, T.J.M., and McLaren, R.A., 1988. "Modelling for digital terrain and landscape visualisation," Photogrammetric Record 12(72):711-45.

    EXAM AND DISCUSSION QUESTIONS

    1. Summarize the ways in which digital displays offer greater flexibility for visualizing spatial data.

    2. The visual system is not the only way in which spatial information might be conveyed to a user. Discuss the prospects for using other methods of communication, either alone or in combination with visual methods. What kind of user interface would be appropriate for a GIS for visually impaired users, and what applications might such a system have?

    3. Review the methods of visualization available in any GIS to which you have access. How limited are they, and how could they be improved?

    4. How would you adapt the concept of an atlas to a digital system with capabilities for animation?


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