Case Study: A Historical Perspective

The vastness of the ocean and the secrets of the submerged landscape contribute to its mystery. Seawater is opaque to light beyond a few hundred meters' penetration. Hence, there are no mountaintops one can scale to directly gaze at vast expanses of the abyssal seafloor.

- William B. F. Ryan, on the problems of mapping the seafloor

History of Seafloor Mapping

The earliest form of navigation on the sea was to keep within constant view of the land. Coastlines where ships sailed regularly were shown in clear detail on maps. Map makers simply guessed at the shapes of other coastlines. Source: National Oceanic and Atmospheric Administration, U.S. Department of Commerce
As a student of marine geology, one of the first things to learn is how we know what we know about the shapes of coastlines and the seafloor. Browse through the following timeline of ocean exploration efforts to find out how humans have developed techniques for mapping coastlines and the seafloor.

Early History


The 1700s

The 1800s

First Bathymetric Map
First attempt at a bathymetric map showing depths of the Atlantic Ocean. Published by Matthew Fontaine Maury in 1855. Source: NOAA

The early 1900s


One of the earliest diagrams of echo-sounding in a published work. Source: F. Spiess' Die Meteor-Fahrt Forschungen, The Meteor Expedition (1928) by F. Speiss.




The 1960s


Modern Era


At the top of this page, you read a quote by William B.F. Ryan in which he focused on the problems of trying to measure and visualize the ocean floor. His quote actually ends by describing a solution to the problem that has been solved using today's technology:

... We visualize the hidden seascape with digital data sets, picture element by picture element, as tiles of a growing quilt, each stitched in the course of month-long expeditions.

-William B. F. Ryan (1992) "An Introduction - Down to the Sea in a Ship" Oceanus, Woods Hole Oceanographic Institution, MA



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