UNIT 11 - SPATIAL OBJECTS AND DATABASE MODELS

UNIT 11 - SPATIAL OBJECTS AND DATABASE MODELS

Compiled with assistance from Timothy L. Nyerges, University of Washington

  • A. INTRODUCTION
  • B. POINT DATA
  • C. LINE DATA
  • D. AREA DATA
  • E. REPRESENTATION OF CONTINUOUS SURFACES
  • REFERENCES
  • EXAM AND DISCUSSION QUESTIONS
  • NOTES

    This unit continues the development of basic concepts about representing reality as spatial data. Here we look at how the representation of reality in the form of entities is handled with the spatial objects points, lines and areas.

    UNIT 11 - SPATIAL OBJECTS AND DATABASE MODELS

    Compiled with assistance from Timothy L. Nyerges, University of Washington

    A. INTRODUCTION

    B. POINT DATA

    C. LINE DATA

    Network entities

    Network characteristics

    Attributes

    Networks as linear addressing systems

    D. AREA DATA

    1. Environmental/natural resource zones

    2. Socio-economic zones

    3. Land records Areal coverage

    Holes and islands

    E. REPRESENTATION OF CONTINUOUS SURFACES

    General nature of surfaces

    Data structures for representing surfaces

    Spatial interpolation

    REFERENCES

    Burrough, P. A., 1986. Geographical Information Systems for Land Resources Assessment, Clarendon Press, Oxford. See chapter 2 for a review of database models.

    Dueker, K. J., 1987. "Geographic Information Systems and Computer-Aided Mapping," American Planning Association Journal, Summer 1987:383-390. Compares database models in GIS and computer mapping.

    Mark, D.M., 1978. "Concepts of Data Structure for Digital Terrain Models," Proceedings of the Digital Terrain Models (DTM) Symposium, ASP and ACSM, pp. 24-31. A comprehensive discussion of DEM database models.

    Marx, R. W., 1986. "The TIGER System: Automating the Geographic Structure of the United States Census," Government Publications Review 13:181-201. Issues in the selection of a database model for TIGER.

    Nyerges, T. L. and K. J. Dueker, 1988. Geographic Information Systems in Transportation, Federal Highway Administration, Division of Planning, Washington, D. C. Database model concerns in transportation applications of GIS.

    Peuquet, D.J., 1984. "A conceptual framework and comparison of spatial data models," Cartographica 21(4):66-113. An

    excellent review of the various spatial data models used in GIS.

    EXAM AND DISCUSSION QUESTIONS

    1. How does a natural zone coverage differ from an enumeration zone coverage? Describe the differences in terms of (a) application areas, (b) visual appearance, (c) compilation of data.

    2. Compare the various data models for elevation data. Which would you expect to be best for (a) a landscape dominated by fluvial erosion and dendritic drainage patterns, (b) a glaciated landscape, (c) a barometric weather map with fronts, (d) a map of population densities for North America.

    3. What data models might be needed in a system to monitor oil spills and potential environmental damage to coastlines? Give examples of appropriate spatial objects and associated attributes.

    4. Describe the differences between the data models commonly used in remote sensing, computer assisted design, automated cartography and GIS.


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