Edisto Island in Colleton County, South Carolina — The American South (South Atlantic)
How to Measure the World, and Why
Photographed By Bernard Fisher, October 20, 2022
1. How to Measure the World, and Why Marker
To map the world, 19th-century surveyors had only triangulation. Here's how it worked: The first step to establish one accurately measured distance, such as the 6.68-mile baseline marked on Edisto Island. Next, surveyors selected a point in the distance and calculated the angle from each end of the baseline to that point. That gave them the length of one side and the two adjacent angles of a huge triangle. Trigonometry could then determine the lengths of the other two sides.To survey a large area, the process was repeated, using old triangles baselines for new ones.
(captions)
Side a is 6.68 miles long. Angle A is 40° and angle B is 75°. We can use a mathematical fomula to learn sides b and c are 9.96 and 9.35 miles respectively.
Starting with a baseline on Edisto lsland, triangulation was used to map South Carolina's shoreline, reducing shipwrecks and saving lives and money. Thomas Cooper Library
Follow this 1/5 mile trail to learn more about the stars of the triangulation story, and Edisto's unique place in navigation histroy.
this page online
Erected by South Carolina State Park Service.
Topics. This historical marker is listed in these topic lists: Exploration • Science & Medicine • Waterways & Vessels. A significant historical year for this entry is 1807.
Location. 32° 30.441′ N, 80° 19.519′ W. Marker is on Edisto Island, South Carolina, in Colleton County. Marker is on Oyster Row Lane, half a mile south of Palmetto Road, on the right when traveling south. Located at the Edisto Environmental Learning Center. Touch for map. Marker is at or near this postal address: Oyster Row Ln, Edisto Island SC 29438, United States of America. Touch for directions.
Other nearby markers. At least 8 other markers are within 12 miles of this marker, measured as the crow flies. The Struggle for a Long Straight Line (within shouting distance of this marker); Markers in the Woods (about 300 feet away, measured in a direct line); Bache's Bar of Invariable Length (about 300 feet away); A Life-Saving Light Station (approx. 11.2 miles away); A Guiding Light (approx. 11.2 miles away); Fuel for the Flame (approx. 11.2 miles away); Island Delivery Service (approx. 11.2 miles away); Harvesting Drinking Water (approx. 11.2 miles away). Touch for a list and map of all markers in Edisto Island.
Also see . . . Edisto Environmental Learning Center. (Submitted on October 20, 2022.)
Photographed By Bernard Fisher, October 20, 2022
2. How to Measure the World, and Why Marker
Photographed By Bernard Fisher, October 20, 2022
3. Edisto Environmental Learning Center
Credits. This page was last revised on October 20, 2022. It was originally submitted on October 20, 2022, by Bernard Fisher of Richmond, Virginia. This page has been viewed 90 times since then and 13 times this year. Photos: 1, 2, 3. submitted on October 20, 2022, by Bernard Fisher of Richmond, Virginia.
