Skip to main content
Geosciences LibreTexts

2: Getting our Bearings

  • Page ID
    4658
  • Learning Objectives

    After reading this chapter, you should be able to:

    • explain the concept of latitude and longitude, and be able to make calculations based on these coordinates
    • explain the advantages and limitations of the various map projections used in oceanography

    • 2.1: Latitude and Longitude
    • 2.2: Measuring Speed
      It was important for mariners to know their speed at sea. Early sailors used chip logs, which were planks of wood attached to long spooled lines containing knots at regular intervals. The plank was thrown overboard, while the spool remained on the ship. Once in the water, the plank encountered drag, which held the plank roughly stationary in the water while the attached line unspooled. The rate at which the line unspooled indicated how fast the ship moved away from the plank, and thus the ship’s
    • 2.3: Map Projections
    • 2.0: Prelude
      People have been navigating the oceans for thousands of years, for exploration, travel, acquiring food, and transporting goods. To do so requires some form of map and the ability to tell direction. Therefore, various systems of navigation have been around for centuries.

    Thumbnail:  The latitude of a point on the Earth’s surface is determined by the angle (ø) between the point and the equator, passing through Earth’s center (Peter Mercator [Public domain], via Wikimedia Commons).