Projections and datums definitions

 

Set of mathematical rules for specifying how coordinates are to be assigned to points that are related to the real world by a datum.

 

Parameter or set of parameters that define the position of the origin, the scale, and the orientation of a coordinate system

 

Distance in a coordinate system, eastwards (positive) and westwards (negative) from a north-south reference line.

 

Surface formed by the rotation of an ellipse about a main axis.

 

Coordinate system in which position is specified by geodetic latitude, geodetic longitude and (in the three-dimensional case) ellipsoidal height.

 

Datum describing the relationship of a coordinate system to the Earth.  A set of constants specifying the coordinate system used for geodetic control. A complete geodetic datum provides, as a minimum, definition for orientation, scale and dimensions for the reference ellipsoid. The concept is generally expanded to include the published coordinates of control stations within the system. 

 

Coordinate conversion from a geodetic/ellipsoidal coordinate system to a plane.

 

Distance in a coordinate system, northwards (positive) or southwards (negative) from an east-west reference line

 

Two-dimensional coordinate system resulting from a map projection.

 

Distance in a coordinate system, southwards (positive) and northwards (negative) from an east-west reference line.

 

Datum describing the relation of gravity-related heights to the earth. In most cases the vertical datum will be related to a defined mean sea level. Ellipsoidal heights are treated as related to a three-dimensional ellipsoidal coordinate system referenced to a geodetic datum.

 

Distance in a coordinate system, westwards (positive) and eastwards (negative) from a north-south reference line.