Fate of the U.S. Survey Foot after 2022: A Conversation with NGS

April 25, 2019  |  2-3 pm, Eastern Time

Dr. Michael Dennis, National Geodetic Survey

Having two feet is great for people, but not so good for standards. Since 1959, two definitions of the foot have been used in the U.S. One is the "international foot", adopted nationwide at that time. The other is the "U.S. survey foot", a renamed perpetuation of the 1893 definition that was intended as temporary. Although the U.S. survey foot is longer by only 2 parts per million (0.01 foot per mile), having both in use at the same time creates real problems with real costs. The result is decades of confusion and chaos in fields where large distances and coordinates are used, such as surveying and mapping. NGS missed an opportunity to fix this problem in 1986, with the change from the NAD 27 to NAD 83 datums. Another opportunity is in 2022 with the modernization of the National Spatial Reference System. This webinar reviews the history of the foot, discusses the vital importance of standards, and gives examples of problems created by having two feet. It shows how NGS can help move the U.S. toward a single, uniform definition of the foot to restore order from chaos.

Beginner Technical Content Rating: No prior knowledge is necessary.