An overview of spatial references Geographic data for any
particular area is stored in separate layers. For example, roads
are stored in one layer, parcels in another, and buildings in a
third. To enable the data in each layer to integrate when
displayed and queried, each layer must reference locations on
the earth's surface in a common way. Coordinate systems provide
this framework. They also provide the framework needed for data
in different regions to be referenced in different ways. Each
layer in the geodatabase has a coordinate system that defines
how its locations are georeferenced. In the geodatabase, the
coordinate system and other related spatial properties are
defined as part of the spatial reference for each dataset. A
spatial reference is the coordinate system used to store each
feature class and raster dataset, as well as other coordinate
properties such as the coordinate resolution for x,y coordinates
and optional z- and measure(m)-coordinates. If required, you can
define a vertical coordinate s