Games

Applications
Title	Games
Author(s)	Rui Barradas Pereira.
Level	Basic
Year of Publication	2011

The availability of consumer GNSS receivers and GNSS enabled mobile devices made possible the use of GNSS for gaming. The oldest and still the most popular GNSS game is Geocaching. Geocaching combines treasure hunt with trekking and outdoor activities.

More recent GNSS based games rely on mobile devices with multimedia interfaces and permanent internet connection. Often these games are multiplayer games that take place in urban environments. Common themes are scavenger hunts, role playing and adventure games.

Application Architecture

GNSS Games depend normally on an architecture that includes a multimedia user mobile device and a game server that collects the different users positions and implements the gameplay.

The user mobile device is usually a mobile phone or smartphone with internet access, localization capabilities and a multimedia user interface.

The process usually followed by these applications is:

• A application running in the user mobile device send the position of the player to a game server.

• The game server gathers the positions of all the players, place the players in the virtual scenario being used in the gameplay, implements the gameplay and sends to the each player its own status or view of the game.

• The player receives in the mobile device the current status sent by the game server and the game application renders on screen the users view of the gameplay. This view normally includes a map with player positions in the virtual scenario of the game.

• In some games there is the possibility of communicating between players.

Variants to this architecture are:

• Game server might not be required for single-player games where the virtual scenarios can be pre-loaded or generated.

• Connection with the game server can be done through SMS. This can include only the communication layer being the user interface done by a local application or can include even the user interface not needing any local application.

• Positioning can be done with celular network based localization.

Geocaching

The oldest and still the most popular GNSS game is Geocaching. Geocaching combines treasure hunt with trekking and outdoor activities.

When GPS Selective Availability was disconnect on March 2^nd 2000, Dave Ulmer, GPS enthusiast, wanted to test the accuracy of GPS to do decided to hide a container with a stash gifts, a log book and a pencil, in the woods in near Beavercreek, Oregon, near Portland.

Dave Ulmer posted the stash coordinates in a satellite navigation newsgroup and the rules were simply: Find the container, register you finding in the log book, take something from the stash and leave something else.

After some days several readers had found the stash and others followed on the idea began hiding their on stashes.

The activity was originaly called GPS Stash Hunt but rapidly was renamed to Geocaching. Rapidly information about caches around the world started to be concentrated in websites such as Geocaching.com.

Currently it is estimated that there are over 5 million geocachers and over 1 million geocaches worldwide. Several variants were created such as multiple caches until reaching the final cache, puzzles to find the cache, moving caches and temporary caches for special events. Geocaching became a outdoor activity normally paired with camping, hiking, biking, boating.

Other Game Examples

The most common types of GNSS games are:

• Scavenger hunts: In this games the player or a team of player needs to collect virtual items by reaching geographically defined spots and collecting the items. Geochaching which is oldest a most popular GNSS games can be considered a form of scavenger hunt.
• Role playing games: Dungeons & Dragons like games where the players can interact with each other when in the vincinity of each others.
• Virtual Boardgames: Games that uses real locations as gameboards. Player assume the role of a character in the game and move around the location to achieve the game objective.
• Adventure game: Adventure games combine virtual worlds with the surroudings of the player. To move around the virtual worlds player need to move in the real world scenario.