A spherical reference system used to measure locations on the Earth's surface. Latitude and longitude are angles measured from the Earth's center to locations on the Earth's surface. Latitude measures angular distance, expressed in degrees, minutes, and seconds along a meridian north or south of the equator. Longitude measures angular distance east or west from a standard meridian to another meridian on the Earth's surface, expressed in degrees, minutes, and seconds. A line is synonymous with an arc.
M map An abstract representation of features on the surface of the Earth.
Map extent is specified in the coordinate system of the coverage or other geographic data set used. A proprietary vector GIS software system developed by MapInfo Corporation. It typically includes information such as currency, accuracy, extent, custodianship, and collection methodology. N node The beginning and ending locations of an arc. A node is topologically linked to all arcs that meet at the node.