Projected Coordinate System


A Projected Coordinate System (PCS) is a type of spatial reference system that represents the three-dimensional earth on a two-dimensional plane. It employs mathematical techniques to convert spherical earth surfaces into flat maps while minimizing distortion as much as possible. This flat representation uses Cartesian (x, y) coordinates to specify locations. An essential aspect of a projected coordinate system is the unit of measure it uses, such as meters or feet.

What is Projected Coordinate System?

A projected coordinate system refers to the transformation of the Earth's curved surface (a geographic coordinate system characterized bylongitude and latitude coordinates) into a flat, 2D surface. This process is carried out using various methods termed as 'projections'. These projections can cause distortion in the area, shape, distance, or direction, and the nature and degree of these distortions are determined by the specific projection used.

The factors that determine the choice of projection include the geographic extent of the area to be mapped and the spatial properties that need to be preserved. The PCS is frequently used in GIS (Geographic Information Systems), remote sensing, cartography, and several other fields that require spatial data analysis over large areas. There is a wide array of projected coordinate systems used worldwide. These include Universal Transverse Mercator (UTM), State Plane Coordinate System (SPS), and Lambert Conformal Conic (LCC).


What is the purpose of a Projected Coordinate System?

The primary purpose of a projected coordinate system is to provide a means to map the rounded earth onto a flat surface, which is achieved through a process called 'projection'. It also allows for more accurate spatial analysis, calculating distances, areas, and directions, especially over large geographic areas.

How is a Projected Coordinate System different from a Geographic Coordinate System?

While a Geographic Coordinate System uses a three-dimensional spherical surface to define locations on the earth, a Projected Coordinate System uses a two-dimensional flat surface. Therefore, Geographic Coordinate Systems describe locations in terms of latitude and longitude while Projected Coordinate Systems describe locations in terms of x and y coordinates.

What are some of the common types of Projected Coordinate Systems?

Some of the widely-used projected coordinate systems include the Universal Transverse Mercator (UTM), State Plane Coordinate System (SPS), and the Lambert Conformal Conic (LCC).

What are the units of measurement in a Projected Coordinate System?

The Projected Coordinate System typically uses linear units of measurement such as meters, feet, or kilometers. These are more intuitive and simpler to use in spatial analysis compared to the decimal degrees used in Geographic Coordinate Systems.

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