GEOG 482
The Nature of Geographic Information

1. Overview


Chapters 6 and 7 consider the origins and characteristics of the framework data themes that make up the United States' proposed National Spatial Data Infrastructure (NSDI). Chapter 6 discussed the geodetic control and orthoimagery themes. This chapter describes the origins, characteristics, and current status of the elevation, transportation, hydrography, governmental units, and cadastral themes.


Students who successfully complete Chapter 7 should be able to:

  1. given a regular or irregular array of spot elevations, construct a triangulated irregular network, interpolate contour intervals and draw contour lines;
  2. compare vector and raster representations of terrain elevation;
  3. acquire and view digital elevation data from the National Elevation Dataset;
  4. calculate an interpolated spot elevation based on neighboring elevations;
  5. contrast the characteristics of three global elevation data products;
  6. describe the characteristics and current status of the NSDI hydrography, transportation, and governmental units themes as implemented in USGS' National Map; and
  7. interpret the size and relative location of a land parcel designated in terms of the U.S. Public Land Survey System.

Comments and Questions

Registered students are welcome to post comments, questions, and replies to questions about the text. Particularly welcome are anecdotes that relate the chapter text to your personal or professional experience. There are discussion forums available in the Canvas course management system for comments and questions.

Penn State logo
Students who register for this Penn State course gain access to assignments and instructor feedback, and earn academic credit. Information about Penn State's Online Geospatial Education programs is available at the Geospatial Education Program Office.