Lesson 4: Map Scale and Spatial Reference Systems

Nicolas MalloyAuthor: Nicolas R. Malloy 

4.1 Overview

Most people have the idea that coordinate systems are static, unchanging definitions of where they are. You can log on to google maps and look up your latitude and longitude coordinates and feel confident that these numbers have a universal meaning that does not change. In reality, the numbers you see on google maps are just one of many versions of latitude and longitude coordinates that can define your location.

Lesson 4 presents the ways in which distance and location are defined and communicated in using scale and spatial reference systems.Defining a position on earth in a way that is meaningful to others is a difficult challenge. In part this is due to the differences in map projections and datums used across the world, which can change longitude and latitude coordinates in different ways. This may seem like a trivial detail, yet boundary definitions and positional information can have significant legal, political, and military consequences.

Learning Outcomes

  • Explain the difference between map scale versus scope
  • Express three ways of representing scale
  • Recognize large-scale and small-scale maps
  • List common distance equivalents
  • Perform scale conversions
  • Determine unknown scale with a variety of references
  • Describe early land partitioning systems
  • Identify the differences between geographic and projected spatial reference systems
  • Demonstrate correct notation for a variety of spatial reference system

Navigating Lesson 4 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.