Geocaching
Channel: 宇宙のすべての知識 プリンシピア
Date: 2019-02-14

Geocaching, by Wikipedia https://en.wikipedia.org/wiki?curid=12533 / CC BY SA 3.0

#Geocaching
#Global_Positioning_System
#Hobbies
#Internet_object_tracking
#Outdoor_locating_games
Geocaching

Geocaching is an outdoor recreational activity, in which participants use a Global Positioning System (GPS) receiver or mobile device and other navigational techniques to hide and seek containers, called "geocaches" or "caches", at specific locations marked by coordinates all over the world.

A typical cache is a small waterproof container containing a logbook and sometimes a pen or pencil. The geocacher signs the log with their established code name and dates it, in order to prove that they found the cache. After signing the log, the cache must be placed back exactly where the person found it. Larger containers such as plastic storage containers (Tupperware or similar) or ammunition boxes can also contain items for trading, such as toys or trinkets, usually of more sentimental worth than financial. Geocaching shares many aspects with benchmarking, trigpointing, orienteering, treasure-hunting, letterboxing, waymarking and Munzee.

Geocaching was originally similar to the 160-year-old game letterboxing, which uses clues and references to landmarks embedded in stories. Geocaching was conceived shortly after the removal of Selective Availability from the Global Positioning System on May 2, 2000, because the improved accuracy of the system allowed for a small container to be specifically placed and located. The first documented placement of a GPS-located cache took place on May 3, 2000, by Dave Ulmer of Beavercreek, Oregon. The location was posted on the Usenet newsgroup sci.geo.satellite-nav at . Within three days, the cache had been found twice, first by Mike Teague. According to Dave Ulmer's message, this cache was a black plastic bucket that was partially buried and contained software, videos, books, money, a can of beans, and a slingshot. 
The geocache and most of its content...