reference frame

Coding an object's location with respect to an external frame of reference involves noting its spatial relations with other objects, usually so-called landmarks that constitute long-term stable reference systems for specific areas (p 14). Encoding the position of the moving self is an essential aspect of spatial orientation, but coding the position of objects relative to the moving self can also be the basis for spatial coding of objects, in addition to or instead of representations using external frames of reference (p 18-19).

Spatial perception and memory are relative,not absolute. The location of one object is coded relative to the location of a reference object, ideally a prominent object in the environment, and also relative to a reference frame, such as the walls and ceiling of a building, large features of the surroundings such as rivers, lakes, and mountains, or the cardinal directions, north, south, east, or west (p 12-13).