Lesson 3: Geodesy and Transformation

Nicolas MalloyAuthor: Nicolas R. Malloy 


3.1 Overview


Since ancient Greece, mathematicians and philosophers have speculated about the size and shape of the earth. The Greek mathematician Pythagoras was one of the first to advocate the idea of a spherical earth. Since then, there have been many estimates on the circumference of the earth by those that followed.

Lesson 3 presents the discipline at the root of geospatial science, geodesy. Geodesy is a branch of applied mathematics. It is the science of measuring and representing the size and shape of the earth, the exact position of points on the earth, and the study of the earth’s gravitational and magnetic fields as they change over time.

 Learning Outcomes


  • Discuss the science and history of geodesy
  • Explain the process of modeling the earth as a mathematically defined surface
  • Describe the elements and purpose of a geodetic datum
  • Recognize commonly used datums for North America
  • Express an understanding of a geographic coordinate system
  • Demonstrate an understanding of geometric transformations and map projections.
  • Recognize common map projections and their uses


Navigating Lesson 3 Page Sections


The table of contents menu on the right outlines individual pages for this lesson. While reading, you may also navigate through pages using the numbered pagination links at the bottom of each page.