Geocaching is an outdoor treasure-hunting game in which the participants use a Global Positioning System (GPS) receiver or other navigational techniques to hide and seek containers (called "geocaches" or "caches") anywhere in the world. A typical cache is a small waterproof container containing a logbook and "treasure," usually toys or trinkets of little value. Today, well over 540,000 geocaches are registered on various websites devoted to the pastime. Geocaches are currently placed in over 100 countries around the world and on all seven continents, including Antarctica.^[1]

History

Geocaching is similar to the 150-year-old letterboxing, which uses references to landmarks and clues embedded in stories. However, geocaching was imagined shortly after the removal of Selective Availability from GPS on May 1, 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^[2]. The location was posted on the Usenet newsgroup sci.geo.satellite-nav ^[3]. By May 6, 2000, it had been found twice and logged once (by Mike Teague of Vancouver, Washington). According to Dave Ulmer's message, the original stash was a black plastic bucket buried most of the way in the ground and contained software, videos, books, food, money, and a slingshot. ^[4]

Origin of the name

The activity was originally referred to as GPS stash hunt or gpsstashing. This was changed after a discussion in the gpsstash discussion group at eGroups (now Yahoo!). On May 30, 2000, Matt Stum suggested that "stash" could have negative connotations, and suggested instead "geocaching."^[5]

Geocaches

For the traditional geocache, a geocacher will place a waterproof container, containing a log book (with pen or pencil) and trinkets or some sort of treasures, then note the cache's coordinates. These coordinates, along with other details of the location, are posted on a website. Other geocachers obtain the coordinates from the Internet and seek out the cache using their GPS handheld receivers. The finding geocachers record their exploits in the logbook and online. Geocachers are free to take objects from the cache in exchange for leaving something of similar or higher value, so there is treasure for the next person to find.

Typical cache treasures are not high in monetary value but may hold personal value to the finder. Aside from the logbook, common cache contents are unusual coins or currency, small toys, ornamental buttons, CDs, or books. Also common are objects that are moved from cache to cache, such as Travel Bugs or Geocoins, whose travels may be logged and followed online. Occasionally, higher value items are included in geocaches, normally reserved for the "first finder", or in locations which are harder to reach.

Geocaches can range in size from film canisters often called "microcaches," too small to hold anything more than a tiny paper log, to those placed in five-gallon buckets or even larger containers. ^[6]

If a geocache has been vandalized or stolen, it is said to have been "muggled" or "plundered." The former term plays off the fact that those not familiar with geocaching are called "geo-muggles" or just muggles, a term borrowed from the Harry Potter series of books.^[7]

If a cacher discovers that a cache has been muggled, it can be logged as needing maintenance, which sends an e-mail to the cache owner so it can be repaired, replaced, or archived (deactivated).

Variations

There are many types of caches. Some are easy enough to be called "drive-bys," "park 'n' grabs" ("PNGs"), or "cache and dash." Others are very difficult, including staged multi-caches;^[8] there are even examples of caches underwater,^[9][10] 50 feet (15 m) up a tree,^[11] after long offroad drives,^[12] on high mountain peaks,^[13] on the Antarctic continent,^[14] and above the Arctic Circle.^[15] Different geocaching websites choose to list different variations as per their own policies (e.g., Geocaching.com does not list new Webcam, Virtual, Locationless, or Moving geocaches).

Variations of geocaches include:

• Traditional: This is the basic cache type. It is a container with a log book (at minimum) found at its listed set of coordinates and usually trade items.
• Night Cache: These traditional caches can only be found at night and involve following a series of reflectors with a flashlight to the final cache location.
• Event Cache: This is a gathering organised and attended by geocachers. Physical caches placed at events are often temporarily placed for the event date only. The Geocaching events category contains some famous annual Geocaching events.
• Cache-In Trash-Out (CITO) Events: This is a variation on event caching. Geocachers gather to clean up the trash in the area to improve the environment as a coordinated activity.
• Letterbox Hybrid: A letterbox hybrid cache is a combination of a geocache and a letterbox in the same container. A letterbox has a rubber stamp and a logbook instead of tradable items. Letterboxers carry their own stamp with them, to stamp the letterbox's log book and inversely stamp their personal log book with the letterbox stamp. The hybrid cache contains the important materials for this and may or may not include trade items. Whether the letterbox hybrid contains trade items is up to the owner.
• Locationless/Reverse: This variation is similar to a scavenger hunt. A description is given for something to find, such as a one-room schoolhouse, and the finder locates an example of this object. The finder records the location using their GPS handheld receiver and often takes a picture at the location showing the named object and his or her GPS receiver. Typically others are not allowed to log that same location as a find. (This is now part of Waymarking.)
• Moving/Traveling: Similar to a traditional geocache, this variation is found at a listed set of coordinates. The finder uses the log book, trades trinkets, and then hides the cache in a different location. By updating this new location on the listing, the finder essentially becomes the hider, and the next finder continues the cycle.
• Multi-cache: This cache consists of multiple caches. These caches are one or more intermediate points containing the coordinates for the next or final cache, that contains the log book and trade items.
• Mystery/puzzle-based: This cache requires one to discover information in order to find the cache. Generally it includes a false set of coordinates within a mile or a couple of kilometers of the cache, and a puzzle must be solved in order to determine the final cache location. In other cases the given location is correct, but the name of the location or other features found there are themselves a puzzle leading to the final cache. Alternatively, additional information is necessary to access the cache (such as a padlock combination) or there are special requirements for logging the find on-line.
• Offset: This cache is similar to the multi-cache except that the initial coordinates are for a location containing information that encodes the final cache coordinates. An example would be to direct the finder to a plaque where the digits of a date on the plaque correspond to coordinates of the final cache.
• Virtual: Caches of this nature are coordinates for a location that does not contain the traditional box, log book, or trade items. Instead, the location contains some other described object. Validation for finding a virtual cache generally requires you to email the cache hider with information such as a date or a name on a plaque, or to post a picture of yourself at the site with GPS receiver in hand.
• Earthcache: Organized and maintained by the Geological Society of America, the EarthCache program is a subset of geocaching in which the "treasure" a cacher finds is not a physical container with trinkets, but an educational lesson of the Earth. The important requirement for an EarthCache to be approved and published is that the cache listing must contain educational information about the earth science of the cache area, and an interactive educational task which directly engages the cacher in that geology. EarthCaches are submitted at www.earthcache.org, and transferred to Groundspeak’s geocaching.com during the review process. The EarthCache program is funded by Groundspeak, National Geographic, Subaru, and the National Park Service.
• Webcam: Similar to a virtual cache; there is no container, log book, or trade items for this cache type. Instead, the coordinates are for a location with a public webcam. Instead of signing a log book, the finder is often required to capture their image from the webcam for verification of the find.

Paperless geocaching

Paperless geocaching is the process of using PDAs or other electronic devices to geocache without having to print out geocache pages. It also gives cachers the capability of doing some impromptu caching if they have some free time and already have cache data on hand for a particular area. Cachers can obtain geocache information (also known as waypoints) from various websites in various formats and load the data into their PDAs to take along with them. Data is generally formatted for use as filetype GPX, which uses XML and contains information describing the geocache and also information about recent visitors to the cache. Other formats exist for storage on various devices, but GPX is the most popular. A variety of programs can translate between the various formats if data is obtained in another program's format.

Obtaining data

Cachers can build their own GPX files with different client software tools, but this task could be very time consuming and prone to data entry error. Some sites allow geocachers to build queries for caches they wish to hunt. They can obtain caches where they want to hunt based on criteria such as Zip Code or coordinates and have it emailed to them as an attachment on a schedule. Other sites allow users to download GPX files directly. By using geocaching software, geocachers can combine and filter cache listings from many sites.

Converting and filtering data

Some cachers convert GPX files to other formats that can be read by their PDA. Others run their GPX files through geocaching Software to change the data for special icons on their GPSr or to filter out caches based on certain criteria. Some applications, especially on Microsoft PocketPC based PDAs, read GPX files directly.

Ethics

When geocaching in busy locations, searching for a cache can require tact and craftiness to avoid the attention of the general public. The person hiding a geocache frequently takes this into account so that the hider and those looking for caches will not cause undue alarm. When care is not taken in hiding or finding a geocache, cachers have been approached by police and questioned when they were seen as acting suspiciously. Other times, investigation of a cache location after suspicious activity was reported has resulted in police and bomb squad discovery of the geocache^[16]. A number of caches have been destroyed by bomb squads.^[17]

Individual geocaching websites have developed their own guidelines for acceptable listings, land agencies and others responsible for public use of land have also established their own guidelines for geocaching and a Geocacher's Creed has also been developed^[18][19]

Websites for geocaching

There are numerous websites that list geocaches around the world. The first and currently the largest^{[citation needed]} is Geocaching.com, which began operating in 2000. This site has members worldwide and hundreds of thousands of caches available. Caches are published by regional cache reviewers, and the site stresses family-oriented caching. There is the basic, free, membership which allows users to see coordinates for most caches in its database, and the premium, paid-subscription accounts which offer additional features and a few more cache sites.

Geocaching.com no longer lists new caches without a physical object, including locationless/reverse and webcam; however, older caches of these types have been grandfathered in (except for locationless/reverse, which have been completely archived). The exception to this is earthcaches, which have been reestablished as caches eligible for new listings. Approval for new earthcaches must be obtained through the Geological Society of America. Groundspeak, Inc., the site's owner, has created a waymarking website, to handle all other non-physical caches.

The next to offer their own cache listing database service^{[citation needed]} was Navicache.com. Started as a regional listing service around February of 2001, Navicache.com quickly gained popularity among those looking for a less restrictive alternatives to what was currently available. They continue to grow and while many of Navicache.com's listings can be found cross-posted to other sites, they also offer many unique listings. Unlike some of the commercial sites, Navicache.com also lists most any type of geocache (within reason) and does not charge to access any of the caches listed in their database. While all submissions still must go through an approval process, they have chosen to be more liberal in approving caches believing that the pastime belongs to the players and therefore should not be controlled by any one entity.

Another geocaching site is TerraCaching.com, whose goal is to have members place and seek caches that are somewhat higher in quality, either from the difficulty of the hide or from the quality of the location. The finders rate every cache they have found. Cache approval is handled by other members through a sponsorship system. Members peer review the quality of other members' caches. It is another worldwide game with caches numbering in the thousands. TerraCaching.com embraces virtual caches alongside traditional/multi-stage caches and has a large selection of locationless caches integrated into the web site.

In the United States, where most geocaching services are hosted, coordinates are not protected by copyright but cache data are. Some commercial web sites listing geocache data are generally protective of their data. People scraping data from geocaching.com have been threatened with lawsuits by Groundspeak, Inc., owners of the site.^{[citation needed]} Navicache.com (and others) continue to take a more 'open-caching' type approach, sharing their database with Buxley's and others.^{[citation needed]}