Coordinate
Systems
The locations of map features are based on a plane Coordinate
System expressed in x- and y- coordinates.
Types of
Coordinate Systems
Coordinates are further categories into two ways.
v
Geographic
Coordinate systems.
v
Projected
Coordinate systems.
Geographic Coordinate Systems
The Geographic Coordinate system is the location reference system
for spatial features on the Earth’s surface. The geographic coordinate system
is defined by longitude and latitude. Both longitude and latitude are angular
measures: longitude measures the angle east and west from the prime meridian,
and latitude measures the angle north or south of the equatorial plane.
Meridians are lines of equal longitude. Parallels are lines if equal latitude.
The angular measures of longitude and latitudes may be expressed in
degrees-minutes-seconds (DMS), decimal degrees (DD),or radians.
Projected Coordinate System
A Projected Coordinate system also called a
plane Coordinate system, is built on a map projection. Projected Coordinate
system are designed for detailed calculations and positioning, and are
typically used in large scale mapping. In
projected Coordinate system X,Y
Coordinates are being converted into units of distance and directions. The
distance is measured in meters and Kilometers. The direction is measured in
false esterning and false northering. The directions are symbolized by + and – signs along with X,Y.
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