Coordinate Reference Systems

When we working on the points of the Earth's surface we need to pin point those locations accurately therefore we need a system to identify and mark those locations for us , and for this reason Coordinate systems are introduced to locate the points on the Earth Surface .Coordinate Reference System specify the locations on the surface of the earth .This uses the referenced data to get the coordinates of the location.

Most common types are Geographic Coordinate Reference Systems and Projected Coordinate Reference System.

Geographic Coordinate Reference Systems : this system uses a set of numbers to denote all the locations of the earth and it is a 3D model uses latitudes and longitudes to measure the location 

 Projected Coordinate Referenced Systems : Flat 2D coordiate system it's based on ( X,Y) points to locate the points on the Earth.It converts the Latituds and longitudes  to get these (X,Y) linear points .

few Examples :
Universal Transverse System ,
State Plane coordinate System.