Blue Switch Day 2026 – Official Blog
When geocachers step out with GPS-equipped devices, they are leveraging decades of brilliant science and mathematics that made those coordinates possible. Behind every successful invention is a brilliant mathematician whose work helped make modern GPS possible: Dr Gladys West.
Photo from the New York Times.
Gladys West’s groundbreaking work focuses on solving a seemingly complex problem: determining the precise shape of the earth.
In the 1960s and 1970s, West helped process large amounts of satellite data to model the Earth’s geoid. Because satellites orbit the Earth based on the Earth’s gravitational field, understanding this shape is important for calculating accurate positions on the planet’s surface. West programmed early supercomputers to analyze oceanographic and satellite measurements, producing increasingly precise models that became the basis for the development of the Global Positioning System (GPS). When GPS satellites were later used, they relied on accurate models of the earth to translate satellite signals into the precise coordinates we use today for navigation, map creation, and location-based technology.
Geocaching is built on a beautifully simple idea: use GPS coordinates to find hidden treasures around the world, but the magic behind these coordinates relies on a highly sophisticated system of satellites, time signals, and models of the Earth.
Thank you, Gladys West, for advancing geodesy and satellite modeling, making geocaching precision possible!
Celebrate Blue Switch Day 2026 by placing a geocache and getting a Blue Switch Day 2026 placer souvenir.
Blue Switch Day 2026 presenters:
- To get this souvenir, geocachers must issue a non-event geocache between May 1 and May 31, 2026.
- Any type of non-event geocache counts (with the exception of Adventure Lab®), as long as it was issued between May 1 and May 31.
- Please note that review times may vary! Geocaching volunteer reviewers will typically begin reviewing your geocache within 7 days. We recommend submitting your cache for publication at least a week before the deadline. Learn more about the cache review process in our Knowledge Base.
How are you celebrating Blue Switch Day this year?
PakarPBN
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The purpose of a PBN is to give the impression that the target website is naturally earning links from multiple independent sources. If done effectively, this can temporarily improve keyword rankings, increase organic visibility, and drive more traffic from search results.
