GEOG 160
Mapping Our Changing World



So far, we have discussed how to collect geographic data, how to manage and manipulate it in a database, and how to represent thematic data in map form. This chapter will explore the various geographic approaches to representing Earth’s surfaces. We will begin the chapter describing topographic maps, from their historical use to their current applications. Next, we will consider different approaches to storing, creating, and representing Earth’s elevation data. Finally, we end the chapter by considering surfaces that are not land-based: bathymetry, the measurements of oceanic depths, or the varying sea floor elevations.


Students who successfully complete Chapter 8 should be able to:

  1. identify different techniques and approaches to representing the Earth’s surfaces;
  2. describe how topographic data are compiled from aerial imagery;
  3. calculate an interpolated spot elevation based on neighboring elevations;
  4. understand how continuous surfaces are created from a set of measured values at discrete locations through interpolation;
  5. given a regular or irregular array of spot elevations, construct a triangulated irregular network, interpolate contour intervals and draw contour lines;
  6. compare vector and raster representations of terrain elevation;
  7. acquire and view digital elevation data from the National Elevation Dataset.

Table of Contents

  • Topographics Maps
  • Elevation 
  • Beyond Terrain Surfaces: Bathymetry
  • Summary
  • Glossary
  • Biblography

Chapter lead author: Jennifer Smith.
Portions of this chapter were drawn directly from the following text: 

Joshua Stevens, Jennifer M. Smith, and Raechel A. Bianchetti (2012), Mapping Our Changing World, Editors: Alan M. MacEachren and Donna J. Peuquet, University Park, PA: Department of Geography, The Pennsylvania State University.