GIS8

Georeferencing
Georeferencing refers to specifying the spatial location to objects and fields.
A georeference must be unique (not shared by two objects),  and must persists through time.
The fundamental problem in georeferencing is how to display 3D features in   2D.
Map projections involve transforming a representation of the world in three           dimensions to a planar surface.
 
Map Projections
Attempt to portray the surface of the earth or a portion of the earth on a flat surface
 Distortions in conformality, distance, direction, area, and scale always occur during projections , Some projections minimize distortions in some of these properties at the expense of others ,Other projections moderately distort all of these properties
Map Projection Classes:  Cylindrical ,  Psuedo-cylindrical ,  Conical ,  Azimuthal
Geocoding:
The process by which spatial locations are determined using coordinate locations specified in a database table,
Terms geocode or geolocate also used, This involves knowledge of coordinate systems, transformation and  projections:
– Cartesian coordinate systems.
– Polar coordinate systems.
– Spherical coordinate systems.