البورشيد

What Is A Geographic Coordinate System? You can think of a Geographic Coordinate Systems as data that is defined by a 3-D surface and measured in latitude and longitude.  An example of a Geographic Coordinate System would be "WGS 1983" or "North American Datum 1983".  You may also wonder what a "Datum" is.  Just remember that the term "Datum" and "Geograhpic Coordinate System" can be used interchangeably.  Essentially a Datum provides a "frame of reference for measureing locations on the surface of the earth i.e. lines of latitude and longitude."  A  geographic coordinate system (GCS)  uses a three-dimensional spherical surface to define locations on the earth. A GCS is often incorrectly called a datum, but a datum is only one part of a GCS. A GCS includes an angular unit of measure, a prime meridian, and a datum (based on a  spheroid ). A point is referenced by its longitude and latitude values. Longitude and latitude