# Chapter 3: Geodesy and Transformation

## Overview

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

Chapter 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 Earth, the exact position of points on the planet, and the study of 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 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