An alphanumeric grid (also known as atlas grid) is a simple
coordinate system on a
grid in which each cell is identified by a combination of a letter and a number.
An advantage over numeric coordinates such as
easting and northing, which use two numbers instead of a number and a letter to refer to a grid cell, is that there can be no confusion over which coordinate refers to which direction. As an easy example, one could think about
battleship; simply match the number at the top to the number on the bottom, then follow the two lines until they meet in a spot.
Algebraic chess notation
Algebraic notation (or AN) is the standard method for recording and describing the moves in a game of chess. It is based on a system of coordinates to uniquely identify each square on the chessboard. It is used by most books, magazines, and news ...
uses an alphanumeric grid to refer to the squares of a
chessboard
A chessboard is a used to play chess. It consists of 64 squares, 8 rows by 8 columns, on which the chess pieces are placed. It is square in shape and uses two colours of squares, one light and one dark, in a chequered pattern. During play, the bo ...
.
[http://www.fide.com/fide/handbook?id=125&view=article ''Appendices'' in World Chess Federation Handbook: see part ''C.7'' of section ''C. Algebraic notation''. Retrieved 2010-03-22.]
Some kinds of
geocode
A geocode is a code that represents a geographic entity (location or object). It is a unique identifier of the entity, to distinguish it from others in a finite set of geographic entities. In general the ''geocode'' is a human-readable an ...
also use letters and numbers, typically several of each in order to specify many more locations over much larger regions.
References
Coordinate systems